From: Perry Yuan <[email protected]>
Hi all,
This patchset implements one new AMD CPU frequency driver
"amd-pstate-epp” instance for better performance and power control.
CPPC has a parameter called energy preference performance (EPP).
The EPP is used in the CCLK DPM controller to drive the frequency that a core
is going to operate during short periods of activity.
EPP values will be utilized for different OS profiles (balanced, performance, power savings).
AMD Energy Performance Preference (EPP) provides a hint to the hardware
if software wants to bias toward performance (0x0) or energy efficiency (0xff)
The lowlevel power firmware will calculate the runtime frequency according to the EPP preference
value. So the EPP hint will impact the CPU cores frequency responsiveness.
We use the RAPL interface with "perf" tool to get the energy data of the package power.
Performance Per Watt (PPW) Calculation:
The PPW calculation is referred by below paper:
https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsoftware.intel.com%2Fcontent%2Fdam%2Fdevelop%2Fexternal%2Fus%2Fen%2Fdocuments%2Fperformance-per-what-paper.pdf&data=04%7C01%7CPerry.Yuan%40amd.com%7Cac66e8ce98044e9b062708d9ab47c8d8%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637729147708574423%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=TPOvCE%2Frbb0ptBreWNxHqOi9YnVhcHGKG88vviDLb00%3D&reserved=0
Below formula is referred from below spec to measure the PPW:
(F / t) / P = F * t / (t * E) = F / E,
"F" is the number of frames per second.
"P" is power measured in watts.
"E" is energy measured in joules.
Gitsouce Benchmark Data on ROME Server CPU
+------------------------------+------------------------------+------------+------------------+
| Kernel Module | PPW (1 / s * J) |Energy(J) | PPW Improvement (%)|
+==============================+==============================+============+==================+
| acpi-cpufreq:schedutil | 5.85658E-05 | 17074.8 | base |
+------------------------------+------------------------------+------------+------------------+
| acpi-cpufreq:ondemand | 5.03079E-05 | 19877.6 | -14.10% |
+------------------------------+------------------------------+------------+------------------+
| acpi-cpufreq:performance | 5.88132E-05 | 17003 | 0.42% |
+------------------------------+------------------------------+------------+------------------+
| amd-pstate:ondemand | 4.60295E-05 | 21725.2 | -21.41% |
+------------------------------+------------------------------+------------+------------------+
| amd-pstate:schedutil | 4.70026E-05 | 21275.4 | -19.7% |
+------------------------------+------------------------------+------------+------------------+
| amd-pstate:performance | 5.80094E-05 | 17238.6 | -0.95% |
+------------------------------+------------------------------+------------+------------------+
| EPP:performance | 5.8292E-05 | 17155 | -0.47% |
+------------------------------+------------------------------+------------+------------------+
| EPP: balance performance: | 6.71709E-05 | 14887.4 | 14.69% |
+------------------------------+------------------------------+------------+------------------+
| EPP:power | 6.66951E-05 | 4993.6 | 13.88% |
+------------------------------+------------------------------+------------+------------------+
Tbench Benchmark Data on ROME Server CPU
+---------------------------------------------+-------------------+--------------+-------------+------------------+
| Kernel Module | PPW MB / (s * J) |Throughput(MB/s)| Energy (J)|PPW Improvement(%)|
+=============================================+===================+==============+=============+==================+
| acpi_cpufreq: schedutil | 46.39 | 17191 | 37057.3 | base |
+---------------------------------------------+-------------------+--------------+-------------+------------------+
| acpi_cpufreq: ondemand | 51.51 | 19269.5 | 37406.5 | 11.04 % |
+---------------------------------------------+-------------------+--------------+-------------+------------------+
| acpi_cpufreq: performance | 45.96 | 17063.7 | 37123.7 | -0.74 % |
+---------------------------------------------+-------------------+--------------+-------------+------------------+
| EPP:powersave: performance(0) | 54.46 | 20263.1 | 37205 | 17.87 % |
+---------------------------------------------+-------------------+--------------+-------------+------------------+
| EPP:powersave: balance performance | 55.03 | 20481.9 | 37221.5 | 19.14 % |
+---------------------------------------------+-------------------+--------------+-------------+------------------+
| EPP:powersave: balance_power | 54.43 | 20245.9 | 37194.2 | 17.77 % |
+---------------------------------------------+-------------------+--------------+-------------+------------------+
| EPP:powersave: power(255) | 54.26 | 20181.7 | 37197.4 | 17.40 % |
+---------------------------------------------+-------------------+--------------+-------------+------------------+
| amd-pstate: schedutil | 48.22 | 17844.9 | 37006.6 | 3.80 % |
+---------------------------------------------+-------------------+--------------+-------------+------------------+
| amd-pstate: ondemand | 61.30 | 22988 | 37503.4 | 33.72 % |
+---------------------------------------------+-------------------+--------------+-------------+------------------+
| amd-pstate: performance | 54.52 | 20252.6 | 37147.8 | 17.81 % |
+---------------------------------------------+-------------------+--------------+-------------+------------------+
changes from v2:
* change pstate driver as builtin type from module
* drop patch "export cpufreq cpu release and acquire"
* squash patch of shared mem into single patch of epp implementation
* add one new patch to support frequency boost control
* add patch to expose driver working status checking
* rebase driver into v6.1-rc4 kernel release
* move some declaration to amd-pstate.h
* drive feedback from Mario for the online/offline patch
* drive feedback from Mario for the suspend/resume patch
* drive feedback from Ray for the cppc_acpi and some other patches
* drive feedback from Nathan for the epp patch
changes from v1:
* rebased to v6.0
* drive feedbacks from Mario for the suspend/resume patch
* drive feedbacks from Nathan for the EPP support on msr type
* fix some typos and code style indent problems
* update commit comments for patch 4/7
* change the `epp_enabled` module param name to `epp`
* set the default epp mode to be false
* add testing for the x86_energy_perf_policy utility patchset(will
send that utility patchset with another thread)
v2: https://lore.kernel.org/all/[email protected]/
v1: https://lore.kernel.org/all/[email protected]/
Perry Yuan (8):
ACPI: CPPC: Add AMD pstate energy performance preference cppc control
Documentation: amd-pstate: add EPP profiles introduction
cpufreq: amd-pstate: change driver to be built-in type
cpufreq: amd_pstate: add AMD Pstate EPP support for the MSR based
processors
cpufreq: amd_pstate: implement amd pstate cpu online and offline
callback
cpufreq: amd-pstate: implement suspend and resume callbacks
cpufreq: amd-pstate: add frequency dynamic boost sysfs control
cpufreq: amd_pstate: add driver working mode status sysfs entry
Documentation/admin-guide/pm/amd-pstate.rst | 19 +
drivers/acpi/cppc_acpi.c | 126 +++
drivers/cpufreq/amd-pstate.c | 905 +++++++++++++++++++-
include/acpi/cppc_acpi.h | 17 +
include/linux/amd-pstate.h | 82 ++
5 files changed, 1135 insertions(+), 14 deletions(-)
--
2.34.1
The patch add AMD pstate EPP feature introduction and what EPP
preference supported for AMD processors.
User can get supported list from
energy_performance_available_preferences attribute file, or update
current profile to energy_performance_preference file
1) See all EPP profiles
$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_available_preferences
default performance balance_performance balance_power power
2) Check current EPP profile
$ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference
performance
3) Set new EPP profile
$ sudo bash -c "echo power > /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference"
Signed-off-by: Perry Yuan <[email protected]>
---
Documentation/admin-guide/pm/amd-pstate.rst | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
index 8f3d30c5a0d8..78c6525d5a49 100644
--- a/Documentation/admin-guide/pm/amd-pstate.rst
+++ b/Documentation/admin-guide/pm/amd-pstate.rst
@@ -262,6 +262,25 @@ lowest non-linear performance in `AMD CPPC Performance Capability
<perf_cap_>`_.)
This attribute is read-only.
+``energy_performance_available_preferences``
+
+All the supported EPP preference could be selected, List of the strings that
+can be set to the ``energy_performance_preference`` attribute
+those different profiles represent different energy vs efficiency hints provided
+to low-level firmware
+however, the ``default`` represents the epp value is set by platform firmware
+This attribute is read-only.
+
+``energy_performance_preference``
+
+The current energy performance preference can be read from this attribute.
+and user can change current preference according to energy or performance needs
+Please get all support profiles list from
+``energy_performance_available_preferences`` attribute, all the profiles are
+integer values defined between 0 to 255 when EPP feature is enabled by platform
+firmware, if EPP feature is disabled, driver will ignore the written value
+This attribute is read-write.
+
Other performance and frequency values can be read back from
``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`.
--
2.34.1
Add EPP driver support for those AMD CPUs which has full MSR feature
enabled, The EPP is used in the DPM controller to drive the frequency
that a core is going to operate during short periods of activity.
EPP values will be utilized for different OS profiles (balanced, performance,
power savings). cppc performance can be controlled by the user space interface
sys attributes for min and max frequency limits, when pstate driver is
working under power save policy.
EPP scale is 0 - 255, 0 is the max performance and 255 is min level.
balance_performance (0x80) can provide best balance performance and watt for
most of system, meanwhile user can choose performance policy on needs.
$ cat /sys/devices/system/cpu/cpufreq/policy0/energy_performance_available_preferences
default performance balance_performance balance_power power
$ cat /sys/devices/system/cpu/cpufreq/policy0/energy_performance_preference
balance_performance
Signed-off-by: Perry Yuan <[email protected]>
---
drivers/cpufreq/amd-pstate.c | 658 ++++++++++++++++++++++++++++++++++-
include/linux/amd-pstate.h | 81 +++++
2 files changed, 734 insertions(+), 5 deletions(-)
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 14906431dc15..eb82bc6a7f66 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -60,8 +60,136 @@
* module parameter to be able to enable it manually for debugging.
*/
static bool shared_mem __read_mostly;
+static int cppc_active __read_mostly;
+static int disable_pstate_load __initdata;
+static int epp_off __initdata;
-static struct cpufreq_driver amd_pstate_driver;
+static struct cpufreq_driver *default_pstate_driver;
+static struct amd_cpudata **all_cpu_data;
+
+static struct amd_pstate_params global_params;
+
+static DEFINE_MUTEX(amd_pstate_limits_lock);
+static DEFINE_MUTEX(amd_pstate_driver_lock);
+
+static bool cppc_boost __read_mostly;
+struct kobject *amd_pstate_kobj;
+
+#ifdef CONFIG_ACPI_CPPC_LIB
+static s16 amd_pstate_get_epp(struct amd_cpudata *cpudata, u64 cppc_req_cached)
+{
+ s16 epp;
+ struct cppc_perf_caps perf_caps;
+ int ret;
+
+ if (boot_cpu_has(X86_FEATURE_CPPC)) {
+ if (!cppc_req_cached) {
+ epp = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ,
+ &cppc_req_cached);
+ if (epp)
+ return epp;
+ }
+ epp = (cppc_req_cached >> 24) & 0xFF;
+ } else {
+ ret = cppc_get_epp_caps(cpudata->cpu, &perf_caps);
+ if (ret < 0) {
+ pr_debug("Could not retrieve energy perf value (%d)\n", ret);
+ return -EIO;
+ }
+ epp = (s16) perf_caps.energy_perf;
+ }
+
+ return epp;
+}
+#endif
+
+static int amd_pstate_get_energy_pref_index(struct amd_cpudata *cpudata, int *raw_epp)
+{
+ s16 epp;
+ int index = -EINVAL;
+
+ *raw_epp = 0;
+ epp = amd_pstate_get_epp(cpudata, 0);
+ if (epp < 0)
+ return epp;
+
+ switch (epp) {
+ case AMD_CPPC_EPP_PERFORMANCE:
+ index = EPP_INDEX_PERFORMANCE;
+ break;
+ case AMD_CPPC_EPP_BALANCE_PERFORMANCE:
+ index = EPP_INDEX_BALANCE_PERFORMANCE;
+ break;
+ case AMD_CPPC_EPP_BALANCE_POWERSAVE:
+ index = EPP_INDEX_BALANCE_POWERSAVE;
+ break;
+ case AMD_CPPC_EPP_POWERSAVE:
+ index = EPP_INDEX_POWERSAVE;
+ break;
+ default:
+ *raw_epp = epp;
+ index = 0;
+ }
+
+ return index;
+}
+
+#ifdef CONFIG_ACPI_CPPC_LIB
+static int amd_pstate_set_epp(struct amd_cpudata *cpudata, u32 epp)
+{
+ int ret;
+ struct cppc_perf_ctrls perf_ctrls;
+
+ if (boot_cpu_has(X86_FEATURE_CPPC)) {
+ u64 value = READ_ONCE(cpudata->cppc_req_cached);
+
+ value &= ~GENMASK_ULL(31, 24);
+ value |= (u64)epp << 24;
+ WRITE_ONCE(cpudata->cppc_req_cached, value);
+
+ ret = wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
+ if (!ret)
+ cpudata->epp_cached = epp;
+ } else {
+ perf_ctrls.energy_perf = epp;
+ ret = cppc_set_epp_perf(cpudata->cpu, &perf_ctrls);
+ if (ret) {
+ pr_debug("failed to set energy perf value (%d)\n", ret);
+ return ret;
+ }
+ cpudata->epp_cached = epp;
+ }
+
+ return ret;
+}
+
+static int amd_pstate_set_energy_pref_index(struct amd_cpudata *cpudata,
+ int pref_index, bool use_raw,
+ u32 raw_epp)
+{
+ int epp = -EINVAL;
+ int ret;
+
+ if (!pref_index) {
+ pr_debug("EPP pref_index is invalid\n");
+ return -EINVAL;
+ }
+
+ if (use_raw)
+ epp = raw_epp;
+ else if (epp == -EINVAL)
+ epp = epp_values[pref_index];
+
+ if (epp > 0 && cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
+ pr_debug("EPP cannot be set under performance policy\n");
+ return -EBUSY;
+ }
+
+ ret = amd_pstate_set_epp(cpudata, epp);
+
+ return ret;
+}
+#endif
static inline int pstate_enable(bool enable)
{
@@ -71,11 +199,25 @@ static inline int pstate_enable(bool enable)
static int cppc_enable(bool enable)
{
int cpu, ret = 0;
+ struct cppc_perf_ctrls perf_ctrls;
for_each_present_cpu(cpu) {
ret = cppc_set_enable(cpu, enable);
if (ret)
return ret;
+
+ /* Enable autonomous mode for EPP */
+ if (!cppc_active) {
+ ret = cppc_set_auto_epp(cpu, enable);
+ if (ret)
+ return ret;
+
+ /* Set desired perf as zero to allow EPP firmware control */
+ perf_ctrls.desired_perf = 0;
+ ret = cppc_set_perf(cpu, &perf_ctrls);
+ if (ret)
+ return ret;
+ }
}
return ret;
@@ -418,7 +560,7 @@ static void amd_pstate_boost_init(struct amd_cpudata *cpudata)
return;
cpudata->boost_supported = true;
- amd_pstate_driver.boost_enabled = true;
+ default_pstate_driver->boost_enabled = true;
}
static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
@@ -582,10 +724,74 @@ static ssize_t show_amd_pstate_highest_perf(struct cpufreq_policy *policy,
return sprintf(&buf[0], "%u\n", perf);
}
+static ssize_t show_energy_performance_available_preferences(
+ struct cpufreq_policy *policy, char *buf)
+{
+ int i = 0;
+ int ret = 0;
+
+ while (energy_perf_strings[i] != NULL)
+ ret += sprintf(&buf[ret], "%s ", energy_perf_strings[i++]);
+
+ ret += sprintf(&buf[ret], "\n");
+
+ return ret;
+}
+
+static ssize_t store_energy_performance_preference(
+ struct cpufreq_policy *policy, const char *buf, size_t count)
+{
+ struct amd_cpudata *cpudata = policy->driver_data;
+ char str_preference[21];
+ bool raw = false;
+ ssize_t ret;
+ u32 epp = 0;
+
+ ret = sscanf(buf, "%20s", str_preference);
+ if (ret != 1)
+ return -EINVAL;
+
+ ret = match_string(energy_perf_strings, -1, str_preference);
+ if (ret < 0) {
+ ret = kstrtouint(buf, 10, &epp);
+ if (ret)
+ return ret;
+
+ if ((epp > 255) || (epp < 0))
+ return -EINVAL;
+
+ raw = true;
+ }
+
+ mutex_lock(&amd_pstate_limits_lock);
+ ret = amd_pstate_set_energy_pref_index(cpudata, ret, raw, epp);
+ mutex_unlock(&amd_pstate_limits_lock);
+
+ return ret ?: count;
+}
+
+static ssize_t show_energy_performance_preference(
+ struct cpufreq_policy *policy, char *buf)
+{
+ struct amd_cpudata *cpudata = policy->driver_data;
+ int preference, raw_epp;
+
+ preference = amd_pstate_get_energy_pref_index(cpudata, &raw_epp);
+ if (preference < 0)
+ return preference;
+
+ if (raw_epp)
+ return sprintf(buf, "%d\n", raw_epp);
+ else
+ return sprintf(buf, "%s\n", energy_perf_strings[preference]);
+}
+
cpufreq_freq_attr_ro(amd_pstate_max_freq);
cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
cpufreq_freq_attr_ro(amd_pstate_highest_perf);
+cpufreq_freq_attr_rw(energy_performance_preference);
+cpufreq_freq_attr_ro(energy_performance_available_preferences);
static struct freq_attr *amd_pstate_attr[] = {
&amd_pstate_max_freq,
@@ -594,6 +800,415 @@ static struct freq_attr *amd_pstate_attr[] = {
NULL,
};
+static struct freq_attr *amd_pstate_epp_attr[] = {
+ &amd_pstate_max_freq,
+ &amd_pstate_lowest_nonlinear_freq,
+ &amd_pstate_highest_perf,
+ &energy_performance_preference,
+ &energy_performance_available_preferences,
+ NULL,
+};
+
+static inline void update_boost_state(void)
+{
+ u64 misc_en;
+ struct amd_cpudata *cpudata;
+
+ cpudata = all_cpu_data[0];
+ rdmsrl(MSR_K7_HWCR, misc_en);
+ global_params.cppc_boost_disabled = misc_en & BIT_ULL(25);
+}
+
+static int amd_pstate_init_cpu(unsigned int cpunum)
+{
+ struct amd_cpudata *cpudata;
+
+ cpudata = all_cpu_data[cpunum];
+ if (!cpudata) {
+ cpudata = kzalloc(sizeof(*cpudata), GFP_KERNEL);
+ if (!cpudata)
+ return -ENOMEM;
+ WRITE_ONCE(all_cpu_data[cpunum], cpudata);
+
+ cpudata->cpu = cpunum;
+ }
+ cpudata->epp_powersave = -EINVAL;
+ cpudata->epp_policy = 0;
+ pr_debug("controlling: cpu %d\n", cpunum);
+ return 0;
+}
+
+static int __amd_pstate_cpu_init(struct cpufreq_policy *policy)
+{
+ int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
+ struct amd_cpudata *cpudata;
+ struct device *dev;
+ int rc;
+ u64 value;
+
+ rc = amd_pstate_init_cpu(policy->cpu);
+ if (rc)
+ return rc;
+
+ cpudata = all_cpu_data[policy->cpu];
+
+ dev = get_cpu_device(policy->cpu);
+ if (!dev)
+ goto free_cpudata1;
+
+ rc = amd_pstate_init_perf(cpudata);
+ if (rc)
+ goto free_cpudata1;
+
+ min_freq = amd_get_min_freq(cpudata);
+ max_freq = amd_get_max_freq(cpudata);
+ nominal_freq = amd_get_nominal_freq(cpudata);
+ lowest_nonlinear_freq = amd_get_lowest_nonlinear_freq(cpudata);
+ if (min_freq < 0 || max_freq < 0 || min_freq > max_freq) {
+ dev_err(dev, "min_freq(%d) or max_freq(%d) value is incorrect\n",
+ min_freq, max_freq);
+ ret = -EINVAL;
+ goto free_cpudata1;
+ }
+
+ policy->min = min_freq;
+ policy->max = max_freq;
+
+ policy->cpuinfo.min_freq = min_freq;
+ policy->cpuinfo.max_freq = max_freq;
+ /* It will be updated by governor */
+ policy->cur = policy->cpuinfo.min_freq;
+
+ /* Initial processor data capability frequencies */
+ cpudata->max_freq = max_freq;
+ cpudata->min_freq = min_freq;
+ cpudata->nominal_freq = nominal_freq;
+ cpudata->lowest_nonlinear_freq = lowest_nonlinear_freq;
+
+ policy->driver_data = cpudata;
+
+ update_boost_state();
+ cpudata->epp_cached = amd_pstate_get_epp(cpudata, value);
+
+ policy->min = policy->cpuinfo.min_freq;
+ policy->max = policy->cpuinfo.max_freq;
+
+ if (boot_cpu_has(X86_FEATURE_CPPC))
+ policy->fast_switch_possible = true;
+
+ if (!shared_mem && boot_cpu_has(X86_FEATURE_CPPC)) {
+ ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, &value);
+ if (ret)
+ return ret;
+ WRITE_ONCE(cpudata->cppc_req_cached, value);
+
+ ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1, &value);
+ if (ret)
+ return ret;
+ WRITE_ONCE(cpudata->cppc_cap1_cached, value);
+ }
+ amd_pstate_boost_init(cpudata);
+
+ return 0;
+
+free_cpudata1:
+ kfree(cpudata);
+ return ret;
+}
+
+static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
+{
+ int ret;
+
+ ret = __amd_pstate_cpu_init(policy);
+ if (ret)
+ return ret;
+ /*
+ * Set the policy to powersave to provide a valid fallback value in case
+ * the default cpufreq governor is neither powersave nor performance.
+ */
+ policy->policy = CPUFREQ_POLICY_POWERSAVE;
+
+ return 0;
+}
+
+static int amd_pstate_epp_cpu_exit(struct cpufreq_policy *policy)
+{
+ pr_debug("amd-pstate: CPU %d exiting\n", policy->cpu);
+ policy->fast_switch_possible = false;
+ return 0;
+}
+
+static void amd_pstate_update_max_freq(unsigned int cpu)
+{
+ struct cpufreq_policy *policy = policy = cpufreq_cpu_get(cpu);
+
+ if (!policy)
+ return;
+
+ refresh_frequency_limits(policy);
+ cpufreq_cpu_put(policy);
+}
+
+static void amd_pstate_epp_update_limits(unsigned int cpu)
+{
+ mutex_lock(&amd_pstate_driver_lock);
+ update_boost_state();
+ if (global_params.cppc_boost_disabled) {
+ for_each_possible_cpu(cpu)
+ amd_pstate_update_max_freq(cpu);
+ } else {
+ cpufreq_update_policy(cpu);
+ }
+ mutex_unlock(&amd_pstate_driver_lock);
+}
+
+static int cppc_boost_hold_time_ns = 3 * NSEC_PER_MSEC;
+
+static inline void amd_pstate_boost_up(struct amd_cpudata *cpudata)
+{
+ u64 hwp_req = READ_ONCE(cpudata->cppc_req_cached);
+ u64 hwp_cap = READ_ONCE(cpudata->cppc_cap1_cached);
+ u32 max_limit = (hwp_req & 0xff);
+ u32 min_limit = (hwp_req & 0xff00) >> 8;
+ u32 boost_level1;
+
+ /* If max and min are equal or already at max, nothing to boost */
+ if (max_limit == min_limit)
+ return;
+
+ /* Set boost max and min to initial value */
+ if (!cpudata->cppc_boost_min)
+ cpudata->cppc_boost_min = min_limit;
+
+ boost_level1 = ((AMD_CPPC_NOMINAL_PERF(hwp_cap) + min_limit) >> 1);
+
+ if (cpudata->cppc_boost_min < boost_level1)
+ cpudata->cppc_boost_min = boost_level1;
+ else if (cpudata->cppc_boost_min < AMD_CPPC_NOMINAL_PERF(hwp_cap))
+ cpudata->cppc_boost_min = AMD_CPPC_NOMINAL_PERF(hwp_cap);
+ else if (cpudata->cppc_boost_min == AMD_CPPC_NOMINAL_PERF(hwp_cap))
+ cpudata->cppc_boost_min = max_limit;
+ else
+ return;
+
+ hwp_req &= ~AMD_CPPC_MIN_PERF(~0L);
+ hwp_req |= AMD_CPPC_MIN_PERF(cpudata->cppc_boost_min);
+ wrmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, hwp_req);
+ cpudata->last_update = cpudata->sample.time;
+}
+
+static inline void amd_pstate_boost_down(struct amd_cpudata *cpudata)
+{
+ bool expired;
+
+ if (cpudata->cppc_boost_min) {
+ expired = time_after64(cpudata->sample.time, cpudata->last_update +
+ cppc_boost_hold_time_ns);
+
+ if (expired) {
+ wrmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ,
+ cpudata->cppc_req_cached);
+ cpudata->cppc_boost_min = 0;
+ }
+ }
+
+ cpudata->last_update = cpudata->sample.time;
+}
+
+static inline void amd_pstate_boost_update_util(struct amd_cpudata *cpudata,
+ u64 time)
+{
+ cpudata->sample.time = time;
+ if (smp_processor_id() != cpudata->cpu)
+ return;
+
+ if (cpudata->sched_flags & SCHED_CPUFREQ_IOWAIT) {
+ bool do_io = false;
+
+ cpudata->sched_flags = 0;
+ /*
+ * Set iowait_boost flag and update time. Since IO WAIT flag
+ * is set all the time, we can't just conclude that there is
+ * some IO bound activity is scheduled on this CPU with just
+ * one occurrence. If we receive at least two in two
+ * consecutive ticks, then we treat as boost candidate.
+ * This is leveraged from Intel Pstate driver.
+ */
+ if (time_before64(time, cpudata->last_io_update + 2 * TICK_NSEC))
+ do_io = true;
+
+ cpudata->last_io_update = time;
+
+ if (do_io)
+ amd_pstate_boost_up(cpudata);
+
+ } else {
+ amd_pstate_boost_down(cpudata);
+ }
+}
+
+static inline void amd_pstate_cppc_update_hook(struct update_util_data *data,
+ u64 time, unsigned int flags)
+{
+ struct amd_cpudata *cpudata = container_of(data,
+ struct amd_cpudata, update_util);
+
+ cpudata->sched_flags |= flags;
+
+ if (smp_processor_id() == cpudata->cpu)
+ amd_pstate_boost_update_util(cpudata, time);
+}
+
+static void amd_pstate_clear_update_util_hook(unsigned int cpu)
+{
+ struct amd_cpudata *cpudata = all_cpu_data[cpu];
+
+ if (!cpudata->update_util_set)
+ return;
+
+ cpufreq_remove_update_util_hook(cpu);
+ cpudata->update_util_set = false;
+ synchronize_rcu();
+}
+
+static void amd_pstate_set_update_util_hook(unsigned int cpu_num)
+{
+ struct amd_cpudata *cpudata = all_cpu_data[cpu_num];
+
+ if (!cppc_boost) {
+ if (cpudata->update_util_set)
+ amd_pstate_clear_update_util_hook(cpudata->cpu);
+ return;
+ }
+
+ if (cpudata->update_util_set)
+ return;
+
+ cpudata->sample.time = 0;
+ cpufreq_add_update_util_hook(cpu_num, &cpudata->update_util,
+ amd_pstate_cppc_update_hook);
+ cpudata->update_util_set = true;
+}
+
+static void amd_pstate_epp_init(unsigned int cpu)
+{
+ struct amd_cpudata *cpudata = all_cpu_data[cpu];
+ u32 max_perf, min_perf;
+ u64 value;
+ s16 epp;
+ int ret;
+
+ max_perf = READ_ONCE(cpudata->highest_perf);
+ min_perf = READ_ONCE(cpudata->lowest_perf);
+
+ value = READ_ONCE(cpudata->cppc_req_cached);
+
+ if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
+ min_perf = max_perf;
+
+ /* Initial min/max values for CPPC Performance Controls Register */
+ value &= ~AMD_CPPC_MIN_PERF(~0L);
+ value |= AMD_CPPC_MIN_PERF(min_perf);
+
+ value &= ~AMD_CPPC_MAX_PERF(~0L);
+ value |= AMD_CPPC_MAX_PERF(max_perf);
+
+ /* CPPC EPP feature require to set zero to the desire perf bit */
+ value &= ~AMD_CPPC_DES_PERF(~0L);
+ value |= AMD_CPPC_DES_PERF(0);
+
+ if (cpudata->epp_policy == cpudata->policy)
+ goto skip_epp;
+
+ cpudata->epp_policy = cpudata->policy;
+
+ if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
+ epp = amd_pstate_get_epp(cpudata, value);
+ cpudata->epp_powersave = epp;
+ if (epp < 0)
+ goto skip_epp;
+ /* force the epp value to be zero for performance policy */
+ epp = 0;
+ } else {
+ if (cpudata->epp_powersave < 0)
+ goto skip_epp;
+ /* Get BIOS pre-defined epp value */
+ epp = amd_pstate_get_epp(cpudata, value);
+ if (epp)
+ goto skip_epp;
+ epp = cpudata->epp_powersave;
+ }
+ /* Set initial EPP value */
+ if (boot_cpu_has(X86_FEATURE_CPPC)) {
+ value &= ~GENMASK_ULL(31, 24);
+ value |= (u64)epp << 24;
+ }
+
+skip_epp:
+ WRITE_ONCE(cpudata->cppc_req_cached, value);
+ ret = wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
+ if (!ret)
+ cpudata->epp_cached = epp;
+}
+
+static void amd_pstate_set_max_limits(struct amd_cpudata *cpudata)
+{
+ u64 hwp_cap = READ_ONCE(cpudata->cppc_cap1_cached);
+ u64 hwp_req = READ_ONCE(cpudata->cppc_req_cached);
+ u32 max_limit = (hwp_cap >> 24) & 0xff;
+
+ hwp_req &= ~AMD_CPPC_MIN_PERF(~0L);
+ hwp_req |= AMD_CPPC_MIN_PERF(max_limit);
+ wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, hwp_req);
+}
+
+static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
+{
+ struct amd_cpudata *cpudata;
+
+ if (!policy->cpuinfo.max_freq)
+ return -ENODEV;
+
+ pr_debug("set_policy: cpuinfo.max %u policy->max %u\n",
+ policy->cpuinfo.max_freq, policy->max);
+
+ cpudata = all_cpu_data[policy->cpu];
+ cpudata->policy = policy->policy;
+
+ if (boot_cpu_has(X86_FEATURE_CPPC)) {
+ mutex_lock(&amd_pstate_limits_lock);
+
+ if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
+ amd_pstate_clear_update_util_hook(policy->cpu);
+ amd_pstate_set_max_limits(cpudata);
+ } else {
+ amd_pstate_set_update_util_hook(policy->cpu);
+ }
+
+ if (boot_cpu_has(X86_FEATURE_CPPC))
+ amd_pstate_epp_init(policy->cpu);
+
+ mutex_unlock(&amd_pstate_limits_lock);
+ }
+
+ return 0;
+}
+
+static void amd_pstate_verify_cpu_policy(struct amd_cpudata *cpudata,
+ struct cpufreq_policy_data *policy)
+{
+ update_boost_state();
+ cpufreq_verify_within_cpu_limits(policy);
+}
+
+static int amd_pstate_epp_verify_policy(struct cpufreq_policy_data *policy)
+{
+ amd_pstate_verify_cpu_policy(all_cpu_data[policy->cpu], policy);
+ pr_debug("policy_max =%d, policy_min=%d\n", policy->max, policy->min);
+ return 0;
+}
+
static struct cpufreq_driver amd_pstate_driver = {
.flags = CPUFREQ_CONST_LOOPS | CPUFREQ_NEED_UPDATE_LIMITS,
.verify = amd_pstate_verify,
@@ -607,8 +1222,20 @@ static struct cpufreq_driver amd_pstate_driver = {
.attr = amd_pstate_attr,
};
+static struct cpufreq_driver amd_pstate_epp_driver = {
+ .flags = CPUFREQ_CONST_LOOPS,
+ .verify = amd_pstate_epp_verify_policy,
+ .setpolicy = amd_pstate_epp_set_policy,
+ .init = amd_pstate_epp_cpu_init,
+ .exit = amd_pstate_epp_cpu_exit,
+ .update_limits = amd_pstate_epp_update_limits,
+ .name = "amd_pstate_epp",
+ .attr = amd_pstate_epp_attr,
+};
+
static int __init amd_pstate_init(void)
{
+ static struct amd_cpudata **cpudata;
int ret;
if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
@@ -623,10 +1250,18 @@ static int __init amd_pstate_init(void)
if (cpufreq_get_current_driver())
return -EEXIST;
+ if (!epp_off) {
+ WRITE_ONCE(cppc_active, 1);
+ if (!default_pstate_driver)
+ default_pstate_driver = &amd_pstate_epp_driver;
+ }
+ pr_info("AMD CPPC loading with %s driver instance.\n", default_pstate_driver->name);
+
/* capability check */
if (boot_cpu_has(X86_FEATURE_CPPC)) {
+ if (!cppc_active)
+ default_pstate_driver->adjust_perf = amd_pstate_adjust_perf;
pr_debug("AMD CPPC MSR based functionality is supported\n");
- amd_pstate_driver.adjust_perf = amd_pstate_adjust_perf;
} else if (shared_mem) {
static_call_update(amd_pstate_enable, cppc_enable);
static_call_update(amd_pstate_init_perf, cppc_init_perf);
@@ -636,6 +1271,10 @@ static int __init amd_pstate_init(void)
return -ENODEV;
}
+ cpudata = vzalloc(array_size(sizeof(void *), num_possible_cpus()));
+ if (!cpudata)
+ return -ENOMEM;
+ WRITE_ONCE(all_cpu_data, cpudata);
/* enable amd pstate feature */
ret = amd_pstate_enable(true);
if (ret) {
@@ -643,9 +1282,9 @@ static int __init amd_pstate_init(void)
return ret;
}
- ret = cpufreq_register_driver(&amd_pstate_driver);
+ ret = cpufreq_register_driver(default_pstate_driver);
if (ret)
- pr_err("failed to register amd_pstate_driver with return %d\n",
+ pr_err("failed to register amd pstate driver with return %d\n",
ret);
return ret;
@@ -657,6 +1296,15 @@ static int __init amd_pstate_param(char *str)
if (!str)
return -EINVAL;
+ if (!strcmp(str, "disable"))
+ disable_pstate_load = 1;
+ else if (!strcmp(str, "active")) {
+ default_pstate_driver = &amd_pstate_epp_driver;
+ } else if (!strcmp(str, "passive")) {
+ epp_off = 1;
+ default_pstate_driver = &amd_pstate_driver;
+ }
+
/* enable shared memory type CPPC ,if you processor has no MSR, you have to add this
* to your grub to make cppc driver loaded successfully.
*/
diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
index 1c4b8659f171..7e6e8cab97b3 100644
--- a/include/linux/amd-pstate.h
+++ b/include/linux/amd-pstate.h
@@ -25,6 +25,7 @@ struct amd_aperf_mperf {
u64 aperf;
u64 mperf;
u64 tsc;
+ u64 time;
};
/**
@@ -47,6 +48,18 @@ struct amd_aperf_mperf {
* @prev: Last Aperf/Mperf/tsc count value read from register
* @freq: current cpu frequency value
* @boost_supported: check whether the Processor or SBIOS supports boost mode
+ * @epp_powersave: Last saved CPPC energy performance preference
+ when policy switched to performance
+ * @epp_policy: Last saved policy used to set energy-performance preference
+ * @epp_cached: Cached CPPC energy-performance preference value
+ * @policy: Cpufreq policy value
+ * @sched_flags: Store scheduler flags for possible cross CPU update
+ * @update_util_set: CPUFreq utility callback is set
+ * @last_update: Time stamp of the last performance state update
+ * @cppc_boost_min: Last CPPC boosted min performance state
+ * @cppc_cap1_cached: Cached value of the last CPPC Capabilities MSR
+ * @update_util: Cpufreq utility callback information
+ * @sample: the stored performance sample
*
* The amd_cpudata is key private data for each CPU thread in AMD P-State, and
* represents all the attributes and goals that AMD P-State requests at runtime.
@@ -72,6 +85,74 @@ struct amd_cpudata {
u64 freq;
bool boost_supported;
+
+ /* EPP feature related attributes*/
+ s16 epp_powersave;
+ s16 epp_policy;
+ s16 epp_cached;
+ u32 policy;
+ u32 sched_flags;
+ bool update_util_set;
+ u64 last_update;
+ u64 last_io_update;
+ u32 cppc_boost_min;
+ u64 cppc_cap1_cached;
+ struct update_util_data update_util;
+ struct amd_aperf_mperf sample;
+};
+
+/**
+ * struct amd_pstate_params - global parameters for the performance control
+ * @ cppc_boost_disabled wheher the core performance boost disabled
+ */
+struct amd_pstate_params {
+ bool cppc_boost_disabled;
+};
+
+#define AMD_CPPC_EPP_PERFORMANCE 0x00
+#define AMD_CPPC_EPP_BALANCE_PERFORMANCE 0x80
+#define AMD_CPPC_EPP_BALANCE_POWERSAVE 0xBF
+#define AMD_CPPC_EPP_POWERSAVE 0xFF
+
+/*
+ * AMD Energy Preference Performance (EPP)
+ * The EPP is used in the CCLK DPM controller to drive
+ * the frequency that a core is going to operate during
+ * short periods of activity. EPP values will be utilized for
+ * different OS profiles (balanced, performance, power savings)
+ * display strings corresponding to EPP index in the
+ * energy_perf_strings[]
+ * index String
+ *-------------------------------------
+ * 0 default
+ * 1 performance
+ * 2 balance_performance
+ * 3 balance_power
+ * 4 power
+ */
+enum energy_perf_value_index {
+ EPP_INDEX_DEFAULT = 0,
+ EPP_INDEX_PERFORMANCE,
+ EPP_INDEX_BALANCE_PERFORMANCE,
+ EPP_INDEX_BALANCE_POWERSAVE,
+ EPP_INDEX_POWERSAVE,
+};
+
+static const char * const energy_perf_strings[] = {
+ [EPP_INDEX_DEFAULT] = "default",
+ [EPP_INDEX_PERFORMANCE] = "performance",
+ [EPP_INDEX_BALANCE_PERFORMANCE] = "balance_performance",
+ [EPP_INDEX_BALANCE_POWERSAVE] = "balance_power",
+ [EPP_INDEX_POWERSAVE] = "power",
+ NULL
+};
+
+static unsigned int epp_values[] = {
+ [EPP_INDEX_DEFAULT] = 0,
+ [EPP_INDEX_PERFORMANCE] = AMD_CPPC_EPP_PERFORMANCE,
+ [EPP_INDEX_BALANCE_PERFORMANCE] = AMD_CPPC_EPP_BALANCE_PERFORMANCE,
+ [EPP_INDEX_BALANCE_POWERSAVE] = AMD_CPPC_EPP_BALANCE_POWERSAVE,
+ [EPP_INDEX_POWERSAVE] = AMD_CPPC_EPP_POWERSAVE,
};
#endif /* _LINUX_AMD_PSTATE_H */
--
2.34.1
While amd-pstate driver was loaded with specific driver mode, it will
need to check which mode is enabled for the pstate driver,add this sysfs
entry to show the current status
$ cat /sys/devices/system/cpu/amd-pstate/status
active
Signed-off-by: Perry Yuan <[email protected]>
---
drivers/cpufreq/amd-pstate.c | 44 ++++++++++++++++++++++++++++++++++++
1 file changed, 44 insertions(+)
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 6958c5fd9e1c..eadcc9d61d39 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -65,6 +65,8 @@ static int disable_pstate_load __initdata;
static int epp_off __initdata;
static struct cpufreq_driver *default_pstate_driver;
+static struct cpufreq_driver amd_pstate_epp_driver;
+static struct cpufreq_driver amd_pstate_driver;
static struct amd_cpudata **all_cpu_data;
static struct amd_pstate_params global_params;
@@ -819,6 +821,46 @@ static ssize_t store_pstate_dynamic_boost(struct kobject *a,
return count;
}
+static ssize_t amd_pstate_show_status(char *buf)
+{
+ if (!default_pstate_driver)
+ return sprintf(buf, "off\n");
+
+ return sprintf(buf, "%s\n", default_pstate_driver == &amd_pstate_epp_driver ?
+ "active" : "passive");
+}
+
+static int amd_pstate_update_status(const char *buf, size_t size)
+{
+ /* FIXME: add driver dynamic switching code */
+ return 0;
+}
+
+static ssize_t show_status(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ ssize_t ret;
+
+ mutex_lock(&amd_pstate_driver_lock);
+ ret = amd_pstate_show_status(buf);
+ mutex_unlock(&amd_pstate_driver_lock);
+
+ return ret;
+}
+
+static ssize_t store_status(struct kobject *a, struct kobj_attribute *b,
+ const char *buf, size_t count)
+{
+ char *p = memchr(buf, '\n', count);
+ int ret;
+
+ mutex_lock(&amd_pstate_driver_lock);
+ ret = amd_pstate_update_status(buf, p ? p - buf : count);
+ mutex_unlock(&amd_pstate_driver_lock);
+
+ return ret < 0 ? ret : count;
+}
+
cpufreq_freq_attr_ro(amd_pstate_max_freq);
cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
@@ -826,6 +868,7 @@ cpufreq_freq_attr_ro(amd_pstate_highest_perf);
cpufreq_freq_attr_rw(energy_performance_preference);
cpufreq_freq_attr_ro(energy_performance_available_preferences);
define_one_global_rw(pstate_dynamic_boost);
+define_one_global_rw(status);
static struct freq_attr *amd_pstate_attr[] = {
&amd_pstate_max_freq,
@@ -845,6 +888,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
static struct attribute *pstate_global_attributes[] = {
&pstate_dynamic_boost.attr,
+ &status.attr,
NULL
};
--
2.34.1
On 11/7/2022 11:57, Perry Yuan wrote:
> While amd-pstate driver was loaded with specific driver mode, it will
> need to check which mode is enabled for the pstate driver,add this sysfs
> entry to show the current status
>
> $ cat /sys/devices/system/cpu/amd-pstate/status
> active >
> Signed-off-by: Perry Yuan <[email protected]>
> ---
> drivers/cpufreq/amd-pstate.c | 44 ++++++++++++++++++++++++++++++++++++
You should update the matching amd-pstate documentation for this new
sysfs file.
> 1 file changed, 44 insertions(+)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 6958c5fd9e1c..eadcc9d61d39 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -65,6 +65,8 @@ static int disable_pstate_load __initdata;
> static int epp_off __initdata;
>
> static struct cpufreq_driver *default_pstate_driver;
> +static struct cpufreq_driver amd_pstate_epp_driver;
> +static struct cpufreq_driver amd_pstate_driver;
> static struct amd_cpudata **all_cpu_data;
>
> static struct amd_pstate_params global_params;
> @@ -819,6 +821,46 @@ static ssize_t store_pstate_dynamic_boost(struct kobject *a,
> return count;
> }
>
> +static ssize_t amd_pstate_show_status(char *buf)
> +{
> + if (!default_pstate_driver)
> + return sprintf(buf, "off\n");
> +
> + return sprintf(buf, "%s\n", default_pstate_driver == &amd_pstate_epp_driver ?
> + "active" : "passive");
> +}
> +
> +static int amd_pstate_update_status(const char *buf, size_t size)
> +{
> + /* FIXME: add driver dynamic switching code */
> + return 0;
> +}
So "Effectively" this is read only right now. I think it's better to
mark the sysfs file as read only and not bother to populate "store"
callback until you're ready to allow dynamically swapping back and forth.
If you want to keep the code there, then I think you should return an
-EOPNOTSUPP error code for amd_pstate_update_status.
> +
> +static ssize_t show_status(struct kobject *kobj,
> + struct kobj_attribute *attr, char *buf)
> +{
> + ssize_t ret;
> +
> + mutex_lock(&amd_pstate_driver_lock);
> + ret = amd_pstate_show_status(buf);
> + mutex_unlock(&amd_pstate_driver_lock);
> +
> + return ret;
> +}
> +
> +static ssize_t store_status(struct kobject *a, struct kobj_attribute *b,
> + const char *buf, size_t count)
> +{
> + char *p = memchr(buf, '\n', count);
> + int ret;
> +
> + mutex_lock(&amd_pstate_driver_lock);
> + ret = amd_pstate_update_status(buf, p ? p - buf : count);
> + mutex_unlock(&amd_pstate_driver_lock);
> +
> + return ret < 0 ? ret : count;
> +}
> +
> cpufreq_freq_attr_ro(amd_pstate_max_freq);
> cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
>
> @@ -826,6 +868,7 @@ cpufreq_freq_attr_ro(amd_pstate_highest_perf);
> cpufreq_freq_attr_rw(energy_performance_preference);
> cpufreq_freq_attr_ro(energy_performance_available_preferences);
> define_one_global_rw(pstate_dynamic_boost);
> +define_one_global_rw(status);
>
> static struct freq_attr *amd_pstate_attr[] = {
> &amd_pstate_max_freq,
> @@ -845,6 +888,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
>
> static struct attribute *pstate_global_attributes[] = {
> &pstate_dynamic_boost.attr,
> + &status.attr,
> NULL
> };
>
Adds online and offline driver callback support to allow cpu cores go
offline and help to restore the previous working states when core goes
back online later for EPP driver mode.
Signed-off-by: Perry Yuan <[email protected]>
---
drivers/cpufreq/amd-pstate.c | 89 ++++++++++++++++++++++++++++++++++++
include/linux/amd-pstate.h | 1 +
2 files changed, 90 insertions(+)
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index eb82bc6a7f66..6ce9fca0a128 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -1195,6 +1195,93 @@ static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
return 0;
}
+static void amd_pstate_epp_reenable(struct amd_cpudata *cpudata)
+{
+ struct cppc_perf_ctrls perf_ctrls;
+ u64 value, max_perf;
+ int ret;
+
+ ret = amd_pstate_enable(true);
+ if (ret)
+ pr_err("failed to enable amd pstate during resume, return %d\n", ret);
+
+ value = READ_ONCE(cpudata->cppc_req_cached);
+ max_perf = READ_ONCE(cpudata->highest_perf);
+
+ if (boot_cpu_has(X86_FEATURE_CPPC)) {
+ wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
+ } else {
+ perf_ctrls.max_perf = max_perf;
+ perf_ctrls.energy_perf = AMD_CPPC_ENERGY_PERF_PREF(cpudata->epp_cached);
+ cppc_set_perf(cpudata->cpu, &perf_ctrls);
+ }
+}
+
+static int amd_pstate_epp_cpu_online(struct cpufreq_policy *policy)
+{
+ struct amd_cpudata *cpudata = all_cpu_data[policy->cpu];
+
+ pr_debug("AMD CPU Core %d going online\n", cpudata->cpu);
+
+ if (cppc_active) {
+ amd_pstate_epp_reenable(cpudata);
+ cpudata->suspended = false;
+ }
+
+ return 0;
+}
+
+static void amd_pstate_epp_offline(struct cpufreq_policy *policy)
+{
+ struct amd_cpudata *cpudata = all_cpu_data[policy->cpu];
+ struct cppc_perf_ctrls perf_ctrls;
+ int min_perf;
+ u64 value;
+
+ min_perf = READ_ONCE(cpudata->lowest_perf);
+ value = READ_ONCE(cpudata->cppc_req_cached);
+
+ mutex_lock(&amd_pstate_limits_lock);
+ if (boot_cpu_has(X86_FEATURE_CPPC)) {
+ cpudata->epp_policy = CPUFREQ_POLICY_UNKNOWN;
+
+ /* Set max perf same as min perf */
+ value &= ~AMD_CPPC_MAX_PERF(~0L);
+ value |= AMD_CPPC_MAX_PERF(min_perf);
+ value &= ~AMD_CPPC_MIN_PERF(~0L);
+ value |= AMD_CPPC_MIN_PERF(min_perf);
+ wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
+ } else {
+ perf_ctrls.desired_perf = 0;
+ perf_ctrls.max_perf = min_perf;
+ perf_ctrls.energy_perf = AMD_CPPC_ENERGY_PERF_PREF(AMD_CPPC_EPP_POWERSAVE);
+ cppc_set_perf(cpudata->cpu, &perf_ctrls);
+ }
+ mutex_unlock(&amd_pstate_limits_lock);
+}
+
+static int amd_pstate_cpu_offline(struct cpufreq_policy *policy)
+{
+ struct amd_cpudata *cpudata = all_cpu_data[policy->cpu];
+
+ pr_debug("AMD CPU Core %d going offline\n", cpudata->cpu);
+
+ if (cpudata->suspended)
+ return 0;
+
+ if (cppc_active)
+ amd_pstate_epp_offline(policy);
+
+ return 0;
+}
+
+static int amd_pstate_epp_cpu_offline(struct cpufreq_policy *policy)
+{
+ amd_pstate_clear_update_util_hook(policy->cpu);
+
+ return amd_pstate_cpu_offline(policy);
+}
+
static void amd_pstate_verify_cpu_policy(struct amd_cpudata *cpudata,
struct cpufreq_policy_data *policy)
{
@@ -1229,6 +1316,8 @@ static struct cpufreq_driver amd_pstate_epp_driver = {
.init = amd_pstate_epp_cpu_init,
.exit = amd_pstate_epp_cpu_exit,
.update_limits = amd_pstate_epp_update_limits,
+ .offline = amd_pstate_epp_cpu_offline,
+ .online = amd_pstate_epp_cpu_online,
.name = "amd_pstate_epp",
.attr = amd_pstate_epp_attr,
};
diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
index 7e6e8cab97b3..c0ad7eedcae3 100644
--- a/include/linux/amd-pstate.h
+++ b/include/linux/amd-pstate.h
@@ -99,6 +99,7 @@ struct amd_cpudata {
u64 cppc_cap1_cached;
struct update_util_data update_util;
struct amd_aperf_mperf sample;
+ bool suspended;
};
/**
--
2.34.1
On 11/7/2022 11:56, Perry Yuan wrote:
> The patch add AMD pstate EPP feature introduction and what EPP
> preference supported for AMD processors.
>
> User can get supported list from
> energy_performance_available_preferences attribute file, or update
> current profile to energy_performance_preference file
>
> 1) See all EPP profiles
> $ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_available_preferences
> default performance balance_performance balance_power power
>
> 2) Check current EPP profile
> $ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference
> performance
>
> 3) Set new EPP profile
> $ sudo bash -c "echo power > /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference"
>
> Signed-off-by: Perry Yuan <[email protected]>
> ---
> Documentation/admin-guide/pm/amd-pstate.rst | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
> index 8f3d30c5a0d8..78c6525d5a49 100644
> --- a/Documentation/admin-guide/pm/amd-pstate.rst
> +++ b/Documentation/admin-guide/pm/amd-pstate.rst
> @@ -262,6 +262,25 @@ lowest non-linear performance in `AMD CPPC Performance Capability
> <perf_cap_>`_.)
> This attribute is read-only.
> > +``energy_performance_available_preferences``
> +
> +All the supported EPP preference could be selected, List of the strings that
> +can be set to the ``energy_performance_preference`` attribute
> +those different profiles represent different energy vs efficiency hints provided
> +to low-level firmware
> +however, the ``default`` represents the epp value is set by platform firmware
> +This attribute is read-only.
My proposal at rewording it.
A list of all the supported EPP preferences that could be used for
``energy_performance_preference` on this system.
These profiles represent different hints that are provided
to the low-level firmware about the user's desired energy vs efficiency
tradeoff. ``default`` represents the epp value is set by platform
firmware. This attribute is read-only.
> +
> +``energy_performance_preference``
> +
> +The current energy performance preference can be read from this attribute.
> +and user can change current preference according to energy or performance needs
> +Please get all support profiles list from
> +``energy_performance_available_preferences`` attribute, all the profiles are
> +integer values defined between 0 to 255 when EPP feature is enabled by platform
> +firmware, if EPP feature is disabled, driver will ignore the written value
> +This attribute is read-write.
> +
> Other performance and frequency values can be read back from
> ``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`.
>
On 11/7/2022 11:57, Perry Yuan wrote:
> Add EPP driver support for those AMD CPUs which has full MSR feature
> enabled, The EPP is used in the DPM controller to drive the frequency
> that a core is going to operate during short periods of activity.
To avoid the run on sentence, here is a different wording proposal.
Add EPP driver support for AMD SoCs which support a dedicated MSR for
CPPC. EPP is used by the DPM controller to configure the frequency that
a core operates at during short periods of activity.
>
> EPP values will be utilized for different OS profiles (balanced, performance,
> power savings). cppc performance can be controlled by the user space interface
> sys attributes for min and max frequency limits, when pstate driver is
> working under power save policy.
>
> EPP scale is 0 - 255, 0 is the max performance and 255 is min level.
> balance_performance (0x80) can provide best balance performance and watt for
> most of system, meanwhile user can choose performance policy on needs.
As a user reading this message it is confusing that there are values and
then there are strings, but you don't know the linkage between the two.
My proposal for rewording this:
The SoC EPP targets are configured on a scale from 0 to 255 where 0
represents maximum performance and 255 represents maximum efficiency.
The amd-pstate driver exports profile string names to userspace that are
tied to specific EPP values.
The balance_performance string (0x80) provides the best balance for
efficiency versus power on most systems, but users can choose other
strings to meet their needs as well.
>
> $ cat /sys/devices/system/cpu/cpufreq/policy0/energy_performance_available_preferences
> default performance balance_performance balance_power power
>
> $ cat /sys/devices/system/cpu/cpufreq/policy0/energy_performance_preference
> balance_performance
>
> Signed-off-by: Perry Yuan <[email protected]>
> ---
> drivers/cpufreq/amd-pstate.c | 658 ++++++++++++++++++++++++++++++++++-
> include/linux/amd-pstate.h | 81 +++++
> 2 files changed, 734 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 14906431dc15..eb82bc6a7f66 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -60,8 +60,136 @@
> * module parameter to be able to enable it manually for debugging.
> */
> static bool shared_mem __read_mostly;
> +static int cppc_active __read_mostly;
> +static int disable_pstate_load __initdata;
> +static int epp_off __initdata;
>
> -static struct cpufreq_driver amd_pstate_driver;
> +static struct cpufreq_driver *default_pstate_driver;
> +static struct amd_cpudata **all_cpu_data;
> +
> +static struct amd_pstate_params global_params;
> +
> +static DEFINE_MUTEX(amd_pstate_limits_lock);
> +static DEFINE_MUTEX(amd_pstate_driver_lock);
> +
> +static bool cppc_boost __read_mostly;
> +struct kobject *amd_pstate_kobj;
> +
> +#ifdef CONFIG_ACPI_CPPC_LIB
> +static s16 amd_pstate_get_epp(struct amd_cpudata *cpudata, u64 cppc_req_cached)
> +{
> + s16 epp;
> + struct cppc_perf_caps perf_caps;
> + int ret;
> +
> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
> + if (!cppc_req_cached) {
> + epp = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ,
> + &cppc_req_cached);
> + if (epp)
> + return epp;
> + }
> + epp = (cppc_req_cached >> 24) & 0xFF;
> + } else {
> + ret = cppc_get_epp_caps(cpudata->cpu, &perf_caps);
> + if (ret < 0) {
> + pr_debug("Could not retrieve energy perf value (%d)\n", ret);
> + return -EIO;
> + }
> + epp = (s16) perf_caps.energy_perf;
> + }
> +
> + return epp;
> +}
> +#endif
> +
> +static int amd_pstate_get_energy_pref_index(struct amd_cpudata *cpudata, int *raw_epp)
> +{
> + s16 epp;
> + int index = -EINVAL;
> +
> + *raw_epp = 0;
> + epp = amd_pstate_get_epp(cpudata, 0);
> + if (epp < 0)
> + return epp;
> +
> + switch (epp) {
> + case AMD_CPPC_EPP_PERFORMANCE:
> + index = EPP_INDEX_PERFORMANCE;
> + break;
> + case AMD_CPPC_EPP_BALANCE_PERFORMANCE:
> + index = EPP_INDEX_BALANCE_PERFORMANCE;
> + break;
> + case AMD_CPPC_EPP_BALANCE_POWERSAVE:
> + index = EPP_INDEX_BALANCE_POWERSAVE;
> + break;
> + case AMD_CPPC_EPP_POWERSAVE:
> + index = EPP_INDEX_POWERSAVE;
> + break;
> + default:
> + *raw_epp = epp;
> + index = 0;
> + }
> +
> + return index;
> +}
> +
> +#ifdef CONFIG_ACPI_CPPC_LIB
> +static int amd_pstate_set_epp(struct amd_cpudata *cpudata, u32 epp)
> +{
> + int ret;
> + struct cppc_perf_ctrls perf_ctrls;
> +
> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
> + u64 value = READ_ONCE(cpudata->cppc_req_cached);
> +
> + value &= ~GENMASK_ULL(31, 24);
> + value |= (u64)epp << 24;
> + WRITE_ONCE(cpudata->cppc_req_cached, value);
> +
> + ret = wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
> + if (!ret)
> + cpudata->epp_cached = epp;
> + } else {
> + perf_ctrls.energy_perf = epp;
> + ret = cppc_set_epp_perf(cpudata->cpu, &perf_ctrls);
> + if (ret) {
> + pr_debug("failed to set energy perf value (%d)\n", ret);
> + return ret;
> + }
> + cpudata->epp_cached = epp;
> + }
> +
> + return ret;
> +}
> +
> +static int amd_pstate_set_energy_pref_index(struct amd_cpudata *cpudata,
> + int pref_index, bool use_raw,
> + u32 raw_epp)
> +{
> + int epp = -EINVAL;
> + int ret;
> +
> + if (!pref_index) {
> + pr_debug("EPP pref_index is invalid\n");
> + return -EINVAL;
> + }
> +
> + if (use_raw)
> + epp = raw_epp;
> + else if (epp == -EINVAL)
> + epp = epp_values[pref_index];
> +
> + if (epp > 0 && cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
> + pr_debug("EPP cannot be set under performance policy\n");
> + return -EBUSY;
> + }
> +
> + ret = amd_pstate_set_epp(cpudata, epp);
> +
> + return ret;
> +}
> +#endif
>
> static inline int pstate_enable(bool enable)
> {
> @@ -71,11 +199,25 @@ static inline int pstate_enable(bool enable)
> static int cppc_enable(bool enable)
> {
> int cpu, ret = 0;
> + struct cppc_perf_ctrls perf_ctrls;
>
> for_each_present_cpu(cpu) {
> ret = cppc_set_enable(cpu, enable);
> if (ret)
> return ret;
> +
> + /* Enable autonomous mode for EPP */
> + if (!cppc_active) {
> + ret = cppc_set_auto_epp(cpu, enable);
> + if (ret)
> + return ret;
> +
> + /* Set desired perf as zero to allow EPP firmware control */
> + perf_ctrls.desired_perf = 0;
> + ret = cppc_set_perf(cpu, &perf_ctrls);
> + if (ret)
> + return ret;
> + }
> }
>
> return ret;
> @@ -418,7 +560,7 @@ static void amd_pstate_boost_init(struct amd_cpudata *cpudata)
> return;
>
> cpudata->boost_supported = true;
> - amd_pstate_driver.boost_enabled = true;
> + default_pstate_driver->boost_enabled = true;
> }
>
> static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
> @@ -582,10 +724,74 @@ static ssize_t show_amd_pstate_highest_perf(struct cpufreq_policy *policy,
> return sprintf(&buf[0], "%u\n", perf);
> }
>
> +static ssize_t show_energy_performance_available_preferences(
> + struct cpufreq_policy *policy, char *buf)
> +{
> + int i = 0;
> + int ret = 0;
> +
> + while (energy_perf_strings[i] != NULL)
> + ret += sprintf(&buf[ret], "%s ", energy_perf_strings[i++]);
> +
> + ret += sprintf(&buf[ret], "\n");
> +
> + return ret;
> +}
> +
> +static ssize_t store_energy_performance_preference(
> + struct cpufreq_policy *policy, const char *buf, size_t count)
> +{
> + struct amd_cpudata *cpudata = policy->driver_data;
> + char str_preference[21];
> + bool raw = false;
> + ssize_t ret;
> + u32 epp = 0;
> +
> + ret = sscanf(buf, "%20s", str_preference);
> + if (ret != 1)
> + return -EINVAL;
> +
> + ret = match_string(energy_perf_strings, -1, str_preference);
> + if (ret < 0) {
> + ret = kstrtouint(buf, 10, &epp);
> + if (ret)
> + return ret;
> +
> + if ((epp > 255) || (epp < 0))
> + return -EINVAL;
> +
> + raw = true;
> + }
What's the reason for supporting putting the raw number in here for
stuff "in between"? I think this is going to pretty confusing to
userspace that you can use string values or integer values. It also
means that if userspace writes an integer with a mapping to string and
tries to read it back they'll get the string rather than the integer!
I can understand using the raw values for internal characterization and
development to possibly introduce a new mapping string, but I don't
think that makes sense in the kernel.
> +
> + mutex_lock(&amd_pstate_limits_lock);
> + ret = amd_pstate_set_energy_pref_index(cpudata, ret, raw, epp);
> + mutex_unlock(&amd_pstate_limits_lock);
> +
> + return ret ?: count;
> +}
> +
> +static ssize_t show_energy_performance_preference(
> + struct cpufreq_policy *policy, char *buf)
> +{
> + struct amd_cpudata *cpudata = policy->driver_data;
> + int preference, raw_epp;
> +
> + preference = amd_pstate_get_energy_pref_index(cpudata, &raw_epp);
> + if (preference < 0)
> + return preference;
> +
> + if (raw_epp)
> + return sprintf(buf, "%d\n", raw_epp);
> + else
> + return sprintf(buf, "%s\n", energy_perf_strings[preference]);
> +}
> +
> cpufreq_freq_attr_ro(amd_pstate_max_freq);
> cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
>
> cpufreq_freq_attr_ro(amd_pstate_highest_perf);
> +cpufreq_freq_attr_rw(energy_performance_preference);
> +cpufreq_freq_attr_ro(energy_performance_available_preferences);
>
> static struct freq_attr *amd_pstate_attr[] = {
> &amd_pstate_max_freq,
> @@ -594,6 +800,415 @@ static struct freq_attr *amd_pstate_attr[] = {
> NULL,
> };
>
> +static struct freq_attr *amd_pstate_epp_attr[] = {
> + &amd_pstate_max_freq,
> + &amd_pstate_lowest_nonlinear_freq,
> + &amd_pstate_highest_perf,
> + &energy_performance_preference,
> + &energy_performance_available_preferences,
> + NULL,
> +};
> +
> +static inline void update_boost_state(void)
> +{
> + u64 misc_en;
> + struct amd_cpudata *cpudata;
> +
> + cpudata = all_cpu_data[0];
> + rdmsrl(MSR_K7_HWCR, misc_en);
> + global_params.cppc_boost_disabled = misc_en & BIT_ULL(25);
> +}
> +
> +static int amd_pstate_init_cpu(unsigned int cpunum)
> +{
> + struct amd_cpudata *cpudata;
> +
> + cpudata = all_cpu_data[cpunum];
> + if (!cpudata) {
> + cpudata = kzalloc(sizeof(*cpudata), GFP_KERNEL);
> + if (!cpudata)
> + return -ENOMEM;
> + WRITE_ONCE(all_cpu_data[cpunum], cpudata);
> +
> + cpudata->cpu = cpunum;
> + }
> + cpudata->epp_powersave = -EINVAL;
> + cpudata->epp_policy = 0;
> + pr_debug("controlling: cpu %d\n", cpunum);
> + return 0;
> +}
> +
> +static int __amd_pstate_cpu_init(struct cpufreq_policy *policy)
> +{
> + int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
> + struct amd_cpudata *cpudata;
> + struct device *dev;
> + int rc;
> + u64 value;
> +
> + rc = amd_pstate_init_cpu(policy->cpu);
> + if (rc)
> + return rc;
> +
> + cpudata = all_cpu_data[policy->cpu];
> +
> + dev = get_cpu_device(policy->cpu);
> + if (!dev)
> + goto free_cpudata1;
> +
> + rc = amd_pstate_init_perf(cpudata);
> + if (rc)
> + goto free_cpudata1;
> +
> + min_freq = amd_get_min_freq(cpudata);
> + max_freq = amd_get_max_freq(cpudata);
> + nominal_freq = amd_get_nominal_freq(cpudata);
> + lowest_nonlinear_freq = amd_get_lowest_nonlinear_freq(cpudata);
> + if (min_freq < 0 || max_freq < 0 || min_freq > max_freq) {
> + dev_err(dev, "min_freq(%d) or max_freq(%d) value is incorrect\n",
> + min_freq, max_freq);
> + ret = -EINVAL;
> + goto free_cpudata1;
> + }
> +
> + policy->min = min_freq;
> + policy->max = max_freq;
> +
> + policy->cpuinfo.min_freq = min_freq;
> + policy->cpuinfo.max_freq = max_freq;
> + /* It will be updated by governor */
> + policy->cur = policy->cpuinfo.min_freq;
> +
> + /* Initial processor data capability frequencies */
> + cpudata->max_freq = max_freq;
> + cpudata->min_freq = min_freq;
> + cpudata->nominal_freq = nominal_freq;
> + cpudata->lowest_nonlinear_freq = lowest_nonlinear_freq;
> +
> + policy->driver_data = cpudata;
> +
> + update_boost_state();
> + cpudata->epp_cached = amd_pstate_get_epp(cpudata, value);
> +
> + policy->min = policy->cpuinfo.min_freq;
> + policy->max = policy->cpuinfo.max_freq;
> +
> + if (boot_cpu_has(X86_FEATURE_CPPC))
> + policy->fast_switch_possible = true;
> +
> + if (!shared_mem && boot_cpu_has(X86_FEATURE_CPPC)) {
> + ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, &value);
> + if (ret)
> + return ret;
> + WRITE_ONCE(cpudata->cppc_req_cached, value);
> +
> + ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1, &value);
> + if (ret)
> + return ret;
> + WRITE_ONCE(cpudata->cppc_cap1_cached, value);
> + }
> + amd_pstate_boost_init(cpudata);
> +
> + return 0;
> +
> +free_cpudata1:
> + kfree(cpudata);
> + return ret;
> +}
> +
> +static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
> +{
> + int ret;
> +
> + ret = __amd_pstate_cpu_init(policy);
> + if (ret)
> + return ret;
> + /*
> + * Set the policy to powersave to provide a valid fallback value in case
> + * the default cpufreq governor is neither powersave nor performance.
> + */
> + policy->policy = CPUFREQ_POLICY_POWERSAVE;
> +
> + return 0;
> +}
> +
> +static int amd_pstate_epp_cpu_exit(struct cpufreq_policy *policy)
> +{
> + pr_debug("amd-pstate: CPU %d exiting\n", policy->cpu);
Drop the "amd-pstate:", this file has pr_fmt.
> + policy->fast_switch_possible = false;
> + return 0;
> +}
> +
> +static void amd_pstate_update_max_freq(unsigned int cpu)
> +{
> + struct cpufreq_policy *policy = policy = cpufreq_cpu_get(cpu);
> +
> + if (!policy)
> + return;
> +
> + refresh_frequency_limits(policy);
> + cpufreq_cpu_put(policy);
> +}
> +
> +static void amd_pstate_epp_update_limits(unsigned int cpu)
> +{
> + mutex_lock(&amd_pstate_driver_lock);
> + update_boost_state();
> + if (global_params.cppc_boost_disabled) {
> + for_each_possible_cpu(cpu)
> + amd_pstate_update_max_freq(cpu);
> + } else {
> + cpufreq_update_policy(cpu);
> + }
> + mutex_unlock(&amd_pstate_driver_lock);
> +}
> +
> +static int cppc_boost_hold_time_ns = 3 * NSEC_PER_MSEC;
> +
> +static inline void amd_pstate_boost_up(struct amd_cpudata *cpudata)
> +{
> + u64 hwp_req = READ_ONCE(cpudata->cppc_req_cached);
> + u64 hwp_cap = READ_ONCE(cpudata->cppc_cap1_cached);
> + u32 max_limit = (hwp_req & 0xff);
> + u32 min_limit = (hwp_req & 0xff00) >> 8;
> + u32 boost_level1;
> +
> + /* If max and min are equal or already at max, nothing to boost */
> + if (max_limit == min_limit)
> + return;
> +
> + /* Set boost max and min to initial value */
> + if (!cpudata->cppc_boost_min)
> + cpudata->cppc_boost_min = min_limit;
> +
> + boost_level1 = ((AMD_CPPC_NOMINAL_PERF(hwp_cap) + min_limit) >> 1);
> +
> + if (cpudata->cppc_boost_min < boost_level1)
> + cpudata->cppc_boost_min = boost_level1;
> + else if (cpudata->cppc_boost_min < AMD_CPPC_NOMINAL_PERF(hwp_cap))
> + cpudata->cppc_boost_min = AMD_CPPC_NOMINAL_PERF(hwp_cap);
> + else if (cpudata->cppc_boost_min == AMD_CPPC_NOMINAL_PERF(hwp_cap))
> + cpudata->cppc_boost_min = max_limit;
> + else
> + return;
> +
> + hwp_req &= ~AMD_CPPC_MIN_PERF(~0L);
> + hwp_req |= AMD_CPPC_MIN_PERF(cpudata->cppc_boost_min);
> + wrmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, hwp_req);
> + cpudata->last_update = cpudata->sample.time;
> +}
> +
> +static inline void amd_pstate_boost_down(struct amd_cpudata *cpudata)
> +{
> + bool expired;
> +
> + if (cpudata->cppc_boost_min) {
> + expired = time_after64(cpudata->sample.time, cpudata->last_update +
> + cppc_boost_hold_time_ns);
> +
> + if (expired) {
> + wrmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ,
> + cpudata->cppc_req_cached);
> + cpudata->cppc_boost_min = 0;
> + }
> + }
> +
> + cpudata->last_update = cpudata->sample.time;
> +}
> +
> +static inline void amd_pstate_boost_update_util(struct amd_cpudata *cpudata,
> + u64 time)
> +{
> + cpudata->sample.time = time;
> + if (smp_processor_id() != cpudata->cpu)
> + return;
> +
> + if (cpudata->sched_flags & SCHED_CPUFREQ_IOWAIT) {
> + bool do_io = false;
> +
> + cpudata->sched_flags = 0;
> + /*
> + * Set iowait_boost flag and update time. Since IO WAIT flag
> + * is set all the time, we can't just conclude that there is
> + * some IO bound activity is scheduled on this CPU with just
> + * one occurrence. If we receive at least two in two
> + * consecutive ticks, then we treat as boost candidate.
> + * This is leveraged from Intel Pstate driver.
> + */
> + if (time_before64(time, cpudata->last_io_update + 2 * TICK_NSEC))
> + do_io = true;
> +
> + cpudata->last_io_update = time;
> +
> + if (do_io)
> + amd_pstate_boost_up(cpudata);
> +
> + } else {
> + amd_pstate_boost_down(cpudata);
> + }
> +}
> +
> +static inline void amd_pstate_cppc_update_hook(struct update_util_data *data,
> + u64 time, unsigned int flags)
> +{
> + struct amd_cpudata *cpudata = container_of(data,
> + struct amd_cpudata, update_util);
> +
> + cpudata->sched_flags |= flags;
> +
> + if (smp_processor_id() == cpudata->cpu)
> + amd_pstate_boost_update_util(cpudata, time);
> +}
> +
> +static void amd_pstate_clear_update_util_hook(unsigned int cpu)
> +{
> + struct amd_cpudata *cpudata = all_cpu_data[cpu];
> +
> + if (!cpudata->update_util_set)
> + return;
> +
> + cpufreq_remove_update_util_hook(cpu);
> + cpudata->update_util_set = false;
> + synchronize_rcu();
> +}
> +
> +static void amd_pstate_set_update_util_hook(unsigned int cpu_num)
> +{
> + struct amd_cpudata *cpudata = all_cpu_data[cpu_num];
> +
> + if (!cppc_boost) {
> + if (cpudata->update_util_set)
> + amd_pstate_clear_update_util_hook(cpudata->cpu);
> + return;
> + }
> +
> + if (cpudata->update_util_set)
> + return;
> +
> + cpudata->sample.time = 0;
> + cpufreq_add_update_util_hook(cpu_num, &cpudata->update_util,
> + amd_pstate_cppc_update_hook);
> + cpudata->update_util_set = true;
> +}
> +
> +static void amd_pstate_epp_init(unsigned int cpu)
> +{
> + struct amd_cpudata *cpudata = all_cpu_data[cpu];
> + u32 max_perf, min_perf;
> + u64 value;
> + s16 epp;
> + int ret;
> +
> + max_perf = READ_ONCE(cpudata->highest_perf);
> + min_perf = READ_ONCE(cpudata->lowest_perf);
> +
> + value = READ_ONCE(cpudata->cppc_req_cached);
> +
> + if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
> + min_perf = max_perf;
> +
> + /* Initial min/max values for CPPC Performance Controls Register */
> + value &= ~AMD_CPPC_MIN_PERF(~0L);
> + value |= AMD_CPPC_MIN_PERF(min_perf);
> +
> + value &= ~AMD_CPPC_MAX_PERF(~0L);
> + value |= AMD_CPPC_MAX_PERF(max_perf);
> +
> + /* CPPC EPP feature require to set zero to the desire perf bit */
> + value &= ~AMD_CPPC_DES_PERF(~0L);
> + value |= AMD_CPPC_DES_PERF(0);
> +
> + if (cpudata->epp_policy == cpudata->policy)
> + goto skip_epp;
> +
> + cpudata->epp_policy = cpudata->policy;
> +
> + if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
> + epp = amd_pstate_get_epp(cpudata, value);
> + cpudata->epp_powersave = epp;
> + if (epp < 0)
> + goto skip_epp;
> + /* force the epp value to be zero for performance policy */
> + epp = 0;
> + } else {
> + if (cpudata->epp_powersave < 0)
> + goto skip_epp;
> + /* Get BIOS pre-defined epp value */
> + epp = amd_pstate_get_epp(cpudata, value);
> + if (epp)
> + goto skip_epp;
> + epp = cpudata->epp_powersave;
> + }
> + /* Set initial EPP value */
> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
> + value &= ~GENMASK_ULL(31, 24);
> + value |= (u64)epp << 24;
> + }
> +
> +skip_epp:
> + WRITE_ONCE(cpudata->cppc_req_cached, value);
> + ret = wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
> + if (!ret)
> + cpudata->epp_cached = epp;
> +}
> +
> +static void amd_pstate_set_max_limits(struct amd_cpudata *cpudata)
> +{
> + u64 hwp_cap = READ_ONCE(cpudata->cppc_cap1_cached);
> + u64 hwp_req = READ_ONCE(cpudata->cppc_req_cached);
> + u32 max_limit = (hwp_cap >> 24) & 0xff;
> +
> + hwp_req &= ~AMD_CPPC_MIN_PERF(~0L);
> + hwp_req |= AMD_CPPC_MIN_PERF(max_limit);
> + wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, hwp_req);
> +}
> +
> +static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
> +{
> + struct amd_cpudata *cpudata;
> +
> + if (!policy->cpuinfo.max_freq)
> + return -ENODEV;
> +
> + pr_debug("set_policy: cpuinfo.max %u policy->max %u\n",
> + policy->cpuinfo.max_freq, policy->max);
> +
> + cpudata = all_cpu_data[policy->cpu];
> + cpudata->policy = policy->policy;
> +
> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
> + mutex_lock(&amd_pstate_limits_lock);
> +
> + if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
> + amd_pstate_clear_update_util_hook(policy->cpu);
> + amd_pstate_set_max_limits(cpudata);
> + } else {
> + amd_pstate_set_update_util_hook(policy->cpu);
> + }
> +
> + if (boot_cpu_has(X86_FEATURE_CPPC))
> + amd_pstate_epp_init(policy->cpu);
> +
> + mutex_unlock(&amd_pstate_limits_lock);
> + }
> +
> + return 0;
> +}
> +
> +static void amd_pstate_verify_cpu_policy(struct amd_cpudata *cpudata,
> + struct cpufreq_policy_data *policy)
> +{
> + update_boost_state();
> + cpufreq_verify_within_cpu_limits(policy);
> +}
> +
> +static int amd_pstate_epp_verify_policy(struct cpufreq_policy_data *policy)
> +{
> + amd_pstate_verify_cpu_policy(all_cpu_data[policy->cpu], policy);
> + pr_debug("policy_max =%d, policy_min=%d\n", policy->max, policy->min);
> + return 0;
> +}
> +
> static struct cpufreq_driver amd_pstate_driver = {
> .flags = CPUFREQ_CONST_LOOPS | CPUFREQ_NEED_UPDATE_LIMITS,
> .verify = amd_pstate_verify,
> @@ -607,8 +1222,20 @@ static struct cpufreq_driver amd_pstate_driver = {
> .attr = amd_pstate_attr,
> };
>
> +static struct cpufreq_driver amd_pstate_epp_driver = {
> + .flags = CPUFREQ_CONST_LOOPS,
> + .verify = amd_pstate_epp_verify_policy,
> + .setpolicy = amd_pstate_epp_set_policy,
> + .init = amd_pstate_epp_cpu_init,
> + .exit = amd_pstate_epp_cpu_exit,
> + .update_limits = amd_pstate_epp_update_limits,
> + .name = "amd_pstate_epp",
> + .attr = amd_pstate_epp_attr,
> +};
> +
> static int __init amd_pstate_init(void)
> {
> + static struct amd_cpudata **cpudata;
> int ret;
>
> if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
> @@ -623,10 +1250,18 @@ static int __init amd_pstate_init(void)
> if (cpufreq_get_current_driver())
> return -EEXIST;
>
> + if (!epp_off) {
> + WRITE_ONCE(cppc_active, 1);
> + if (!default_pstate_driver)
> + default_pstate_driver = &amd_pstate_epp_driver;
> + }
> + pr_info("AMD CPPC loading with %s driver instance.\n", default_pstate_driver->name);
This is pretty noisy, do we really need it on every boot if we can
easily check it from sysfs?
> +
> /* capability check */
> if (boot_cpu_has(X86_FEATURE_CPPC)) {
> + if (!cppc_active)
> + default_pstate_driver->adjust_perf = amd_pstate_adjust_perf;
> pr_debug("AMD CPPC MSR based functionality is supported\n");
> - amd_pstate_driver.adjust_perf = amd_pstate_adjust_perf;
> } else if (shared_mem) {
> static_call_update(amd_pstate_enable, cppc_enable);
> static_call_update(amd_pstate_init_perf, cppc_init_perf);
> @@ -636,6 +1271,10 @@ static int __init amd_pstate_init(void)
> return -ENODEV;
> }
>
> + cpudata = vzalloc(array_size(sizeof(void *), num_possible_cpus()));
> + if (!cpudata)
> + return -ENOMEM;
> + WRITE_ONCE(all_cpu_data, cpudata);
> /* enable amd pstate feature */
> ret = amd_pstate_enable(true);
> if (ret) {
> @@ -643,9 +1282,9 @@ static int __init amd_pstate_init(void)
> return ret;
> }
>
> - ret = cpufreq_register_driver(&amd_pstate_driver);
> + ret = cpufreq_register_driver(default_pstate_driver);
> if (ret)
> - pr_err("failed to register amd_pstate_driver with return %d\n",
> + pr_err("failed to register amd pstate driver with return %d\n",
> ret);
>
> return ret;
> @@ -657,6 +1296,15 @@ static int __init amd_pstate_param(char *str)
> if (!str)
> return -EINVAL;
>
> + if (!strcmp(str, "disable"))
> + disable_pstate_load = 1;
> + else if (!strcmp(str, "active")) {
> + default_pstate_driver = &amd_pstate_epp_driver;
> + } else if (!strcmp(str, "passive")) {
> + epp_off = 1;
> + default_pstate_driver = &amd_pstate_driver;
> + }
> +
> /* enable shared memory type CPPC ,if you processor has no MSR, you have to add this
> * to your grub to make cppc driver loaded successfully.
> */
> diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
> index 1c4b8659f171..7e6e8cab97b3 100644
> --- a/include/linux/amd-pstate.h
> +++ b/include/linux/amd-pstate.h
> @@ -25,6 +25,7 @@ struct amd_aperf_mperf {
> u64 aperf;
> u64 mperf;
> u64 tsc;
> + u64 time;
> };
>
> /**
> @@ -47,6 +48,18 @@ struct amd_aperf_mperf {
> * @prev: Last Aperf/Mperf/tsc count value read from register
> * @freq: current cpu frequency value
> * @boost_supported: check whether the Processor or SBIOS supports boost mode
> + * @epp_powersave: Last saved CPPC energy performance preference
> + when policy switched to performance
> + * @epp_policy: Last saved policy used to set energy-performance preference
> + * @epp_cached: Cached CPPC energy-performance preference value
> + * @policy: Cpufreq policy value
> + * @sched_flags: Store scheduler flags for possible cross CPU update
> + * @update_util_set: CPUFreq utility callback is set
> + * @last_update: Time stamp of the last performance state update
> + * @cppc_boost_min: Last CPPC boosted min performance state
> + * @cppc_cap1_cached: Cached value of the last CPPC Capabilities MSR
> + * @update_util: Cpufreq utility callback information
> + * @sample: the stored performance sample
> *
> * The amd_cpudata is key private data for each CPU thread in AMD P-State, and
> * represents all the attributes and goals that AMD P-State requests at runtime.
> @@ -72,6 +85,74 @@ struct amd_cpudata {
>
> u64 freq;
> bool boost_supported;
> +
> + /* EPP feature related attributes*/
> + s16 epp_powersave;
> + s16 epp_policy;
> + s16 epp_cached;
> + u32 policy;
> + u32 sched_flags;
> + bool update_util_set;
> + u64 last_update;
> + u64 last_io_update;
> + u32 cppc_boost_min;
> + u64 cppc_cap1_cached;
> + struct update_util_data update_util;
> + struct amd_aperf_mperf sample;
> +};
> +
> +/**
> + * struct amd_pstate_params - global parameters for the performance control
> + * @ cppc_boost_disabled wheher the core performance boost disabled
> + */
> +struct amd_pstate_params {
> + bool cppc_boost_disabled;
> +};
> +
> +#define AMD_CPPC_EPP_PERFORMANCE 0x00
> +#define AMD_CPPC_EPP_BALANCE_PERFORMANCE 0x80
> +#define AMD_CPPC_EPP_BALANCE_POWERSAVE 0xBF
> +#define AMD_CPPC_EPP_POWERSAVE 0xFF
> +
> +/*
> + * AMD Energy Preference Performance (EPP)
> + * The EPP is used in the CCLK DPM controller to drive
> + * the frequency that a core is going to operate during
> + * short periods of activity. EPP values will be utilized for
> + * different OS profiles (balanced, performance, power savings)
> + * display strings corresponding to EPP index in the
> + * energy_perf_strings[]
> + * index String
> + *-------------------------------------
> + * 0 default
> + * 1 performance
> + * 2 balance_performance
> + * 3 balance_power
> + * 4 power
> + */
> +enum energy_perf_value_index {
> + EPP_INDEX_DEFAULT = 0,
> + EPP_INDEX_PERFORMANCE,
> + EPP_INDEX_BALANCE_PERFORMANCE,
> + EPP_INDEX_BALANCE_POWERSAVE,
> + EPP_INDEX_POWERSAVE,
> +};
> +
> +static const char * const energy_perf_strings[] = {
> + [EPP_INDEX_DEFAULT] = "default",
> + [EPP_INDEX_PERFORMANCE] = "performance",
> + [EPP_INDEX_BALANCE_PERFORMANCE] = "balance_performance",
> + [EPP_INDEX_BALANCE_POWERSAVE] = "balance_power",
> + [EPP_INDEX_POWERSAVE] = "power",
> + NULL
> +};
> +
> +static unsigned int epp_values[] = {
> + [EPP_INDEX_DEFAULT] = 0,
> + [EPP_INDEX_PERFORMANCE] = AMD_CPPC_EPP_PERFORMANCE,
> + [EPP_INDEX_BALANCE_PERFORMANCE] = AMD_CPPC_EPP_BALANCE_PERFORMANCE,
> + [EPP_INDEX_BALANCE_POWERSAVE] = AMD_CPPC_EPP_BALANCE_POWERSAVE,
> + [EPP_INDEX_POWERSAVE] = AMD_CPPC_EPP_POWERSAVE,
> };
>
> #endif /* _LINUX_AMD_PSTATE_H */
Hi Perry,
I love your patch! Perhaps something to improve:
[auto build test WARNING on rafael-pm/linux-next]
[also build test WARNING on linus/master v6.1-rc4 next-20221107]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Perry-Yuan/Implement-AMD-Pstate-EPP-Driver/20221108-020418
base: https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
patch link: https://lore.kernel.org/r/20221107175705.2207842-5-Perry.Yuan%40amd.com
patch subject: [PATCH v3 4/8] cpufreq: amd_pstate: add AMD Pstate EPP support for the MSR based processors
config: i386-allyesconfig
compiler: gcc-11 (Debian 11.3.0-8) 11.3.0
reproduce (this is a W=1 build):
# https://github.com/intel-lab-lkp/linux/commit/3d16457032d0668bcaa51c537e74f6e1aa0c9a73
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Perry-Yuan/Implement-AMD-Pstate-EPP-Driver/20221108-020418
git checkout 3d16457032d0668bcaa51c537e74f6e1aa0c9a73
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/cpufreq/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
drivers/cpufreq/amd-pstate.c: In function 'amd_pstate_get_energy_pref_index':
drivers/cpufreq/amd-pstate.c:112:15: error: implicit declaration of function 'amd_pstate_get_epp' [-Werror=implicit-function-declaration]
112 | epp = amd_pstate_get_epp(cpudata, 0);
| ^~~~~~~~~~~~~~~~~~
drivers/cpufreq/amd-pstate.c: In function 'store_energy_performance_preference':
drivers/cpufreq/amd-pstate.c:767:15: error: implicit declaration of function 'amd_pstate_set_energy_pref_index'; did you mean 'amd_pstate_get_energy_pref_index'? [-Werror=implicit-function-declaration]
767 | ret = amd_pstate_set_energy_pref_index(cpudata, ret, raw, epp);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| amd_pstate_get_energy_pref_index
drivers/cpufreq/amd-pstate.c: In function 'update_boost_state':
>> drivers/cpufreq/amd-pstate.c:815:29: warning: variable 'cpudata' set but not used [-Wunused-but-set-variable]
815 | struct amd_cpudata *cpudata;
| ^~~~~~~
In file included from drivers/cpufreq/amd-pstate.c:39:
At top level:
include/linux/amd-pstate.h:150:21: warning: 'epp_values' defined but not used [-Wunused-variable]
150 | static unsigned int epp_values[] = {
| ^~~~~~~~~~
cc1: some warnings being treated as errors
vim +/cpudata +815 drivers/cpufreq/amd-pstate.c
811
812 static inline void update_boost_state(void)
813 {
814 u64 misc_en;
> 815 struct amd_cpudata *cpudata;
816
817 cpudata = all_cpu_data[0];
818 rdmsrl(MSR_K7_HWCR, misc_en);
819 global_params.cppc_boost_disabled = misc_en & BIT_ULL(25);
820 }
821
--
0-DAY CI Kernel Test Service
https://01.org/lkp
Hi Perry,
I love your patch! Yet something to improve:
[auto build test ERROR on rafael-pm/linux-next]
[also build test ERROR on linus/master v6.1-rc4 next-20221108]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Perry-Yuan/Implement-AMD-Pstate-EPP-Driver/20221108-020418
base: https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
patch link: https://lore.kernel.org/r/20221107175705.2207842-5-Perry.Yuan%40amd.com
patch subject: [PATCH v3 4/8] cpufreq: amd_pstate: add AMD Pstate EPP support for the MSR based processors
config: i386-allyesconfig
compiler: gcc-11 (Debian 11.3.0-8) 11.3.0
reproduce (this is a W=1 build):
# https://github.com/intel-lab-lkp/linux/commit/3d16457032d0668bcaa51c537e74f6e1aa0c9a73
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Perry-Yuan/Implement-AMD-Pstate-EPP-Driver/20221108-020418
git checkout 3d16457032d0668bcaa51c537e74f6e1aa0c9a73
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
drivers/cpufreq/amd-pstate.c: In function 'amd_pstate_get_energy_pref_index':
>> drivers/cpufreq/amd-pstate.c:112:15: error: implicit declaration of function 'amd_pstate_get_epp' [-Werror=implicit-function-declaration]
112 | epp = amd_pstate_get_epp(cpudata, 0);
| ^~~~~~~~~~~~~~~~~~
drivers/cpufreq/amd-pstate.c: In function 'store_energy_performance_preference':
>> drivers/cpufreq/amd-pstate.c:767:15: error: implicit declaration of function 'amd_pstate_set_energy_pref_index'; did you mean 'amd_pstate_get_energy_pref_index'? [-Werror=implicit-function-declaration]
767 | ret = amd_pstate_set_energy_pref_index(cpudata, ret, raw, epp);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| amd_pstate_get_energy_pref_index
drivers/cpufreq/amd-pstate.c: In function 'update_boost_state':
drivers/cpufreq/amd-pstate.c:815:29: warning: variable 'cpudata' set but not used [-Wunused-but-set-variable]
815 | struct amd_cpudata *cpudata;
| ^~~~~~~
In file included from drivers/cpufreq/amd-pstate.c:39:
At top level:
include/linux/amd-pstate.h:150:21: warning: 'epp_values' defined but not used [-Wunused-variable]
150 | static unsigned int epp_values[] = {
| ^~~~~~~~~~
cc1: some warnings being treated as errors
vim +/amd_pstate_get_epp +112 drivers/cpufreq/amd-pstate.c
105
106 static int amd_pstate_get_energy_pref_index(struct amd_cpudata *cpudata, int *raw_epp)
107 {
108 s16 epp;
109 int index = -EINVAL;
110
111 *raw_epp = 0;
> 112 epp = amd_pstate_get_epp(cpudata, 0);
113 if (epp < 0)
114 return epp;
115
116 switch (epp) {
117 case AMD_CPPC_EPP_PERFORMANCE:
118 index = EPP_INDEX_PERFORMANCE;
119 break;
120 case AMD_CPPC_EPP_BALANCE_PERFORMANCE:
121 index = EPP_INDEX_BALANCE_PERFORMANCE;
122 break;
123 case AMD_CPPC_EPP_BALANCE_POWERSAVE:
124 index = EPP_INDEX_BALANCE_POWERSAVE;
125 break;
126 case AMD_CPPC_EPP_POWERSAVE:
127 index = EPP_INDEX_POWERSAVE;
128 break;
129 default:
130 *raw_epp = epp;
131 index = 0;
132 }
133
134 return index;
135 }
136
--
0-DAY CI Kernel Test Service
https://01.org/lkp
[AMD Official Use Only - General]
Hi Rafael.
> -----Original Message-----
> From: Rafael J. Wysocki <[email protected]>
> Sent: Thursday, November 10, 2022 10:58 PM
> To: Yuan, Perry <[email protected]>
> Cc: [email protected]; Huang, Ray <[email protected]>;
> [email protected]; Sharma, Deepak <[email protected]>;
> Limonciello, Mario <[email protected]>; Fontenot, Nathan
> <[email protected]>; Deucher, Alexander
> <[email protected]>; Huang, Shimmer
> <[email protected]>; Du, Xiaojian <[email protected]>; Meng,
> Li (Jassmine) <[email protected]>; [email protected]; linux-
> [email protected]
> Subject: Re: [PATCH v3 2/8] Documentation: amd-pstate: add EPP profiles
> introduction
>
> Caution: This message originated from an External Source. Use proper
> caution when opening attachments, clicking links, or responding.
>
>
> On Mon, Nov 7, 2022 at 7:02 PM Perry Yuan <[email protected]> wrote:
> >
> > The patch add AMD pstate EPP feature introduction and what EPP
> > preference supported for AMD processors.
> >
> > User can get supported list from
> > energy_performance_available_preferences attribute file, or update
> > current profile to energy_performance_preference file
> >
> > 1) See all EPP profiles
> > $ sudo cat
> >
> /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_available_pr
> ef
> > erences default performance balance_performance balance_power power
> >
> > 2) Check current EPP profile
> > $ sudo cat
> > /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference
> > performance
> >
> > 3) Set new EPP profile
> > $ sudo bash -c "echo power >
> /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference"
> >
> > Signed-off-by: Perry Yuan <[email protected]>
> > ---
> > Documentation/admin-guide/pm/amd-pstate.rst | 19
> +++++++++++++++++++
> > 1 file changed, 19 insertions(+)
> >
> > diff --git a/Documentation/admin-guide/pm/amd-pstate.rst
> > b/Documentation/admin-guide/pm/amd-pstate.rst
> > index 8f3d30c5a0d8..78c6525d5a49 100644
> > --- a/Documentation/admin-guide/pm/amd-pstate.rst
> > +++ b/Documentation/admin-guide/pm/amd-pstate.rst
> > @@ -262,6 +262,25 @@ lowest non-linear performance in `AMD CPPC
> > Performance Capability
> > <perf_cap_>`_.)
> > This attribute is read-only.
> >
> > +``energy_performance_available_preferences``
> > +
> > +All the supported EPP preference could be selected, List of the
> > +strings that can be set to the ``energy_performance_preference``
> > +attribute those different profiles represent different energy vs
> > +efficiency hints provided to low-level firmware however, the
> > +``default`` represents the epp value is set by platform firmware This
> > +attribute is read-only.
> > +
> > +``energy_performance_preference``
> > +
> > +The current energy performance preference can be read from this
> attribute.
> > +and user can change current preference according to energy or
> > +performance needs Please get all support profiles list from
> > +``energy_performance_available_preferences`` attribute, all the
> > +profiles are integer values defined between 0 to 255 when EPP feature
> > +is enabled by platform firmware, if EPP feature is disabled, driver
> > +will ignore the written value This attribute is read-write.
> > +
> > Other performance and frequency values can be read back from
> > ``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`.
> >
> > --
>
> So the interface is the same as for intel_pstate AFAICS, which is good,
> because it is all consistent.
>
> However, there is some code duplication introduced in the subsequent
> patches and that may be a problem from the perspective of maintaining that
> consistency in the future.
>
> Have you at least considered introducing a common EPP support header file
> that could be used by both intel_pstate and amd_pstate?
I will send the V4 today, that will change the epp value set and get interface
To be compatible with the Gnome power preference setting sysfs call, I use the same profile names.
But V4 patch will there is no raw_epp support as the suggested by Mario.
I will also think about what else can make as common code in the driver scale.
Thanks for your suggestions.
Perry.
On Mon, Nov 7, 2022 at 7:02 PM Perry Yuan <[email protected]> wrote:
>
> The patch add AMD pstate EPP feature introduction and what EPP
> preference supported for AMD processors.
>
> User can get supported list from
> energy_performance_available_preferences attribute file, or update
> current profile to energy_performance_preference file
>
> 1) See all EPP profiles
> $ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_available_preferences
> default performance balance_performance balance_power power
>
> 2) Check current EPP profile
> $ sudo cat /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference
> performance
>
> 3) Set new EPP profile
> $ sudo bash -c "echo power > /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference"
>
> Signed-off-by: Perry Yuan <[email protected]>
> ---
> Documentation/admin-guide/pm/amd-pstate.rst | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/Documentation/admin-guide/pm/amd-pstate.rst b/Documentation/admin-guide/pm/amd-pstate.rst
> index 8f3d30c5a0d8..78c6525d5a49 100644
> --- a/Documentation/admin-guide/pm/amd-pstate.rst
> +++ b/Documentation/admin-guide/pm/amd-pstate.rst
> @@ -262,6 +262,25 @@ lowest non-linear performance in `AMD CPPC Performance Capability
> <perf_cap_>`_.)
> This attribute is read-only.
>
> +``energy_performance_available_preferences``
> +
> +All the supported EPP preference could be selected, List of the strings that
> +can be set to the ``energy_performance_preference`` attribute
> +those different profiles represent different energy vs efficiency hints provided
> +to low-level firmware
> +however, the ``default`` represents the epp value is set by platform firmware
> +This attribute is read-only.
> +
> +``energy_performance_preference``
> +
> +The current energy performance preference can be read from this attribute.
> +and user can change current preference according to energy or performance needs
> +Please get all support profiles list from
> +``energy_performance_available_preferences`` attribute, all the profiles are
> +integer values defined between 0 to 255 when EPP feature is enabled by platform
> +firmware, if EPP feature is disabled, driver will ignore the written value
> +This attribute is read-write.
> +
> Other performance and frequency values can be read back from
> ``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`.
>
> --
So the interface is the same as for intel_pstate AFAICS, which is
good, because it is all consistent.
However, there is some code duplication introduced in the subsequent
patches and that may be a problem from the perspective of maintaining
that consistency in the future.
Have you at least considered introducing a common EPP support header
file that could be used by both intel_pstate and amd_pstate?
On 11/7/22 11:57, Perry Yuan wrote:
> While amd-pstate driver was loaded with specific driver mode, it will
> need to check which mode is enabled for the pstate driver,add this sysfs
> entry to show the current status
>
> $ cat /sys/devices/system/cpu/amd-pstate/status
> active
>
> Signed-off-by: Perry Yuan <[email protected]>
> ---
> drivers/cpufreq/amd-pstate.c | 44 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 44 insertions(+)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 6958c5fd9e1c..eadcc9d61d39 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -65,6 +65,8 @@ static int disable_pstate_load __initdata;
> static int epp_off __initdata;
>
> static struct cpufreq_driver *default_pstate_driver;
> +static struct cpufreq_driver amd_pstate_epp_driver;
> +static struct cpufreq_driver amd_pstate_driver;
> static struct amd_cpudata **all_cpu_data;
>
> static struct amd_pstate_params global_params;
> @@ -819,6 +821,46 @@ static ssize_t store_pstate_dynamic_boost(struct kobject *a,
> return count;
> }
>
> +static ssize_t amd_pstate_show_status(char *buf)
> +{
> + if (!default_pstate_driver)
> + return sprintf(buf, "off\n");
> +
> + return sprintf(buf, "%s\n", default_pstate_driver == &amd_pstate_epp_driver ?
> + "active" : "passive");
> +}
> +
> +static int amd_pstate_update_status(const char *buf, size_t size)
> +{
> + /* FIXME: add driver dynamic switching code */
> + return 0;
> +}
> +
> +static ssize_t show_status(struct kobject *kobj,
> + struct kobj_attribute *attr, char *buf)
> +{
> + ssize_t ret;
> +
> + mutex_lock(&amd_pstate_driver_lock);
> + ret = amd_pstate_show_status(buf);
> + mutex_unlock(&amd_pstate_driver_lock);
Do we really need to take a lock to show the driver status?
-Nathan
> +
> + return ret;
> +}
> +
> +static ssize_t store_status(struct kobject *a, struct kobj_attribute *b,
> + const char *buf, size_t count)
> +{
> + char *p = memchr(buf, '\n', count);
> + int ret;
> +
> + mutex_lock(&amd_pstate_driver_lock);
> + ret = amd_pstate_update_status(buf, p ? p - buf : count);
> + mutex_unlock(&amd_pstate_driver_lock);
> +
> + return ret < 0 ? ret : count;
> +}
> +
> cpufreq_freq_attr_ro(amd_pstate_max_freq);
> cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
>
> @@ -826,6 +868,7 @@ cpufreq_freq_attr_ro(amd_pstate_highest_perf);
> cpufreq_freq_attr_rw(energy_performance_preference);
> cpufreq_freq_attr_ro(energy_performance_available_preferences);
> define_one_global_rw(pstate_dynamic_boost);
> +define_one_global_rw(status);
>
> static struct freq_attr *amd_pstate_attr[] = {
> &amd_pstate_max_freq,
> @@ -845,6 +888,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
>
> static struct attribute *pstate_global_attributes[] = {
> &pstate_dynamic_boost.attr,
> + &status.attr,
> NULL
> };
>
[AMD Official Use Only - General]
Hi Nathan.
> -----Original Message-----
> From: Fontenot, Nathan <[email protected]>
> Sent: Friday, November 11, 2022 12:00 AM
> To: Limonciello, Mario <[email protected]>; Yuan, Perry
> <[email protected]>; [email protected]; Huang, Ray
> <[email protected]>; [email protected]
> Cc: Sharma, Deepak <[email protected]>; Deucher, Alexander
> <[email protected]>; Huang, Shimmer
> <[email protected]>; Du, Xiaojian <[email protected]>; Meng,
> Li (Jassmine) <[email protected]>; [email protected]; linux-
> [email protected]
> Subject: Re: [PATCH v3 4/8] cpufreq: amd_pstate: add AMD Pstate EPP
> support for the MSR based processors
>
>
>
> On 11/7/22 14:32, Limonciello, Mario wrote:
> > On 11/7/2022 11:57, Perry Yuan wrote:
> >> Add EPP driver support for those AMD CPUs which has full MSR feature
> >> enabled, The EPP is used in the DPM controller to drive the frequency
> >> that a core is going to operate during short periods of activity.
> >
> > To avoid the run on sentence, here is a different wording proposal.
> >
> > Add EPP driver support for AMD SoCs which support a dedicated MSR for
> CPPC. EPP is used by the DPM controller to configure the frequency that a
> core operates at during short periods of activity.
> >
> >>
> >> EPP values will be utilized for different OS profiles (balanced,
> >> performance, power savings). cppc performance can be controlled by
> >> the user space interface sys attributes for min and max frequency
> >> limits, when pstate driver is working under power save policy.
> >>
> >> EPP scale is 0 - 255, 0 is the max performance and 255 is min level.
> >> balance_performance (0x80) can provide best balance performance and
> >> watt for most of system, meanwhile user can choose performance policy
> on needs.
> >
> > As a user reading this message it is confusing that there are values and then
> there are strings, but you don't know the linkage between the two. My
> proposal for rewording this:
> >
> > The SoC EPP targets are configured on a scale from 0 to 255 where 0
> represents maximum performance and 255 represents maximum efficiency.
> >
> > The amd-pstate driver exports profile string names to userspace that are
> tied to specific EPP values.
> >
> > The balance_performance string (0x80) provides the best balance for
> efficiency versus power on most systems, but users can choose other strings
> to meet their needs as well.
> >
> >>
> >> $ cat
> >>
> /sys/devices/system/cpu/cpufreq/policy0/energy_performance_available_
> >> preferences default performance balance_performance balance_power
> >> power
> >>
> >> $ cat
> >>
> /sys/devices/system/cpu/cpufreq/policy0/energy_performance_preferenc
> e
> >> balance_performance
> >>
> >> Signed-off-by: Perry Yuan <[email protected]>
> >> ---
> >> drivers/cpufreq/amd-pstate.c | 658
> >> ++++++++++++++++++++++++++++++++++-
> >> include/linux/amd-pstate.h | 81 +++++
> >> 2 files changed, 734 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/drivers/cpufreq/amd-pstate.c
> >> b/drivers/cpufreq/amd-pstate.c index 14906431dc15..eb82bc6a7f66
> >> 100644
> >> --- a/drivers/cpufreq/amd-pstate.c
> >> +++ b/drivers/cpufreq/amd-pstate.c
> >> @@ -60,8 +60,136 @@
> >> * module parameter to be able to enable it manually for debugging.
> >> */
> >> static bool shared_mem __read_mostly;
> >> +static int cppc_active __read_mostly; static int disable_pstate_load
> >> +__initdata; static int epp_off __initdata;
> >> -static struct cpufreq_driver amd_pstate_driver;
> >> +static struct cpufreq_driver *default_pstate_driver; static struct
> >> +amd_cpudata **all_cpu_data;
> >> +
> >> +static struct amd_pstate_params global_params;
> >> +
> >> +static DEFINE_MUTEX(amd_pstate_limits_lock);
> >> +static DEFINE_MUTEX(amd_pstate_driver_lock);
> >> +
> >> +static bool cppc_boost __read_mostly; struct kobject
> >> +*amd_pstate_kobj;
> >> +
> >> +#ifdef CONFIG_ACPI_CPPC_LIB
> >> +static s16 amd_pstate_get_epp(struct amd_cpudata *cpudata, u64
> >> +cppc_req_cached) {
> >> + s16 epp;
> >> + struct cppc_perf_caps perf_caps;
> >> + int ret;
> >> +
> >> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
> >> + if (!cppc_req_cached) {
> >> + epp = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ,
> >> + &cppc_req_cached);
> >> + if (epp)
> >> + return epp;
> >> + }
> >> + epp = (cppc_req_cached >> 24) & 0xFF;
> >> + } else {
> >> + ret = cppc_get_epp_caps(cpudata->cpu, &perf_caps);
> >> + if (ret < 0) {
> >> + pr_debug("Could not retrieve energy perf value (%d)\n",
> >> +ret);
> >> + return -EIO;
> >> + }
> >> + epp = (s16) perf_caps.energy_perf;
> >> + }
> >> +
> >> + return epp;
> >> +}
> >> +#endif
> >> +
> >> +static int amd_pstate_get_energy_pref_index(struct amd_cpudata
> >> +*cpudata, int *raw_epp) {
> >> + s16 epp;
> >> + int index = -EINVAL;
> >> +
> >> + *raw_epp = 0;
> >> + epp = amd_pstate_get_epp(cpudata, 0);
> >> + if (epp < 0)
> >> + return epp;
> >> +
> >> + switch (epp) {
> >> + case AMD_CPPC_EPP_PERFORMANCE:
> >> + index = EPP_INDEX_PERFORMANCE;
> >> + break;
> >> + case AMD_CPPC_EPP_BALANCE_PERFORMANCE:
> >> + index = EPP_INDEX_BALANCE_PERFORMANCE;
> >> + break;
> >> + case AMD_CPPC_EPP_BALANCE_POWERSAVE:
> >> + index = EPP_INDEX_BALANCE_POWERSAVE;
> >> + break;
> >> + case AMD_CPPC_EPP_POWERSAVE:
> >> + index = EPP_INDEX_POWERSAVE;
> >> + break;
> >> + default:
> >> + *raw_epp = epp;
> >> + index = 0;
> >> + }
> >> +
> >> + return index;
> >> +}
> >> +
> >> +#ifdef CONFIG_ACPI_CPPC_LIB
> >> +static int amd_pstate_set_epp(struct amd_cpudata *cpudata, u32 epp)
> >> +{
> >> + int ret;
> >> + struct cppc_perf_ctrls perf_ctrls;
> >> +
> >> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
> >> + u64 value = READ_ONCE(cpudata->cppc_req_cached);
> >> +
> >> + value &= ~GENMASK_ULL(31, 24);
> >> + value |= (u64)epp << 24;
> >> + WRITE_ONCE(cpudata->cppc_req_cached, value);
> >> +
> >> + ret = wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
> >> + if (!ret)
> >> + cpudata->epp_cached = epp;
> >> + } else {
> >> + perf_ctrls.energy_perf = epp;
> >> + ret = cppc_set_epp_perf(cpudata->cpu, &perf_ctrls);
> >> + if (ret) {
> >> + pr_debug("failed to set energy perf value (%d)\n", ret);
> >> + return ret;
> >> + }
> >> + cpudata->epp_cached = epp;
> >> + }
> >> +
> >> + return ret;
> >> +}
> >> +
> >> +static int amd_pstate_set_energy_pref_index(struct amd_cpudata
> >> +*cpudata,
> >> + int pref_index, bool use_raw,
> >> + u32 raw_epp) {
> >> + int epp = -EINVAL;
> >> + int ret;
> >> +
> >> + if (!pref_index) {
> >> + pr_debug("EPP pref_index is invalid\n");
> >> + return -EINVAL;
> >> + }
> >> +
> >> + if (use_raw)
> >> + epp = raw_epp;
> >> + else if (epp == -EINVAL)
> >> + epp = epp_values[pref_index];
> >> +
> >> + if (epp > 0 && cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
> >> + pr_debug("EPP cannot be set under performance policy\n");
> >> + return -EBUSY;
> >> + }
> >> +
> >> + ret = amd_pstate_set_epp(cpudata, epp);
> >> +
> >> + return ret;
> >> +}
> >> +#endif
> >> static inline int pstate_enable(bool enable)
> >> {
> >> @@ -71,11 +199,25 @@ static inline int pstate_enable(bool enable)
> >> static int cppc_enable(bool enable)
> >> {
> >> int cpu, ret = 0;
> >> + struct cppc_perf_ctrls perf_ctrls;
> >> for_each_present_cpu(cpu) {
> >> ret = cppc_set_enable(cpu, enable);
> >> if (ret)
> >> return ret;
> >> +
> >> + /* Enable autonomous mode for EPP */
> >> + if (!cppc_active) {
> >> + ret = cppc_set_auto_epp(cpu, enable);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + /* Set desired perf as zero to allow EPP firmware
> >> +control */
> >> + perf_ctrls.desired_perf = 0;
> >> + ret = cppc_set_perf(cpu, &perf_ctrls);
> >> + if (ret)
> >> + return ret;
> >> + }
> >> }
> >> return ret;
> >> @@ -418,7 +560,7 @@ static void amd_pstate_boost_init(struct
> >> amd_cpudata *cpudata)
> >> return;
> >> cpudata->boost_supported = true;
> >> - amd_pstate_driver.boost_enabled = true;
> >> + default_pstate_driver->boost_enabled = true;
> >> }
> >> static int amd_pstate_cpu_init(struct cpufreq_policy *policy) @@
> >> -582,10 +724,74 @@ static ssize_t show_amd_pstate_highest_perf(struct
> >> cpufreq_policy *policy,
> >> return sprintf(&buf[0], "%u\n", perf);
> >> }
> >> +static ssize_t show_energy_performance_available_preferences(
> >> + struct cpufreq_policy *policy, char *buf) {
> >> + int i = 0;
> >> + int ret = 0;
> >> +
> >> + while (energy_perf_strings[i] != NULL)
> >> + ret += sprintf(&buf[ret], "%s ", energy_perf_strings[i++]);
> >> +
> >> + ret += sprintf(&buf[ret], "\n");
> >> +
> >> + return ret;
> >> +}
> >> +
> >> +static ssize_t store_energy_performance_preference(
> >> + struct cpufreq_policy *policy, const char *buf, size_t
> >> +count) {
> >> + struct amd_cpudata *cpudata = policy->driver_data;
> >> + char str_preference[21];
> >> + bool raw = false;
> >> + ssize_t ret;
> >> + u32 epp = 0;
> >> +
> >> + ret = sscanf(buf, "%20s", str_preference);
> >> + if (ret != 1)
> >> + return -EINVAL;
> >> +
> >> + ret = match_string(energy_perf_strings, -1, str_preference);
> >> + if (ret < 0) {
> >> + ret = kstrtouint(buf, 10, &epp);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + if ((epp > 255) || (epp < 0))
> >> + return -EINVAL;
> >> +
> >> + raw = true;
> >> + }
> >
> > What's the reason for supporting putting the raw number in here for stuff
> "in between"? I think this is going to pretty confusing to userspace that you
> can use string values or integer values. It also means that if userspace writes
> an integer with a mapping to string and tries to read it back they'll get the
> string rather than the integer!
> >
> > I can understand using the raw values for internal characterization and
> development to possibly introduce a new mapping string, but I don't think
> that makes sense in the kernel.
> >
>
> This is really doing what Intel does for handling EPP settings. Yes, writing a
> value and getting back a string could be a bit confusing bit it is already done
> from the Intel side. I think keeping EPP value setting common would be a
> good thing if we can do it.
>
> I don't think we should remove the ability to set raw values, we're allowed a
> range of 0 - 255 for the EPP setting. Why we then limit ourselves to only 4 or
> so values?
>
> -Nathan
The raw values are userd for tunning , we have another utility to fine tune the performance/power under development.
So from the customer perspective, we do not need to keep the raw epp set any more in my opinion.
And Mario also has strong justification for the change.
Perry.
>
> >> +
> >> + mutex_lock(&amd_pstate_limits_lock);
> >> + ret = amd_pstate_set_energy_pref_index(cpudata, ret, raw, epp);
> >> + mutex_unlock(&amd_pstate_limits_lock);
> >> +
> >> + return ret ?: count;
> >> +}
> >> +
> >> +static ssize_t show_energy_performance_preference(
> >> + struct cpufreq_policy *policy, char *buf) {
> >> + struct amd_cpudata *cpudata = policy->driver_data;
> >> + int preference, raw_epp;
> >> +
> >> + preference = amd_pstate_get_energy_pref_index(cpudata,
> >> +&raw_epp);
> >> + if (preference < 0)
> >> + return preference;
> >> +
> >> + if (raw_epp)
> >> + return sprintf(buf, "%d\n", raw_epp);
> >> + else
> >> + return sprintf(buf, "%s\n",
> >> +energy_perf_strings[preference]); }
> >> +
> >> cpufreq_freq_attr_ro(amd_pstate_max_freq);
> >> cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
> >> cpufreq_freq_attr_ro(amd_pstate_highest_perf);
> >> +cpufreq_freq_attr_rw(energy_performance_preference);
> >> +cpufreq_freq_attr_ro(energy_performance_available_preferences);
> >> static struct freq_attr *amd_pstate_attr[] = {
> >> &amd_pstate_max_freq,
> >> @@ -594,6 +800,415 @@ static struct freq_attr *amd_pstate_attr[] = {
> >> NULL,
> >> };
> >> +static struct freq_attr *amd_pstate_epp_attr[] = {
> >> + &amd_pstate_max_freq,
> >> + &amd_pstate_lowest_nonlinear_freq,
> >> + &amd_pstate_highest_perf,
> >> + &energy_performance_preference,
> >> + &energy_performance_available_preferences,
> >> + NULL,
> >> +};
> >> +
> >> +static inline void update_boost_state(void) {
> >> + u64 misc_en;
> >> + struct amd_cpudata *cpudata;
> >> +
> >> + cpudata = all_cpu_data[0];
> >> + rdmsrl(MSR_K7_HWCR, misc_en);
> >> + global_params.cppc_boost_disabled = misc_en & BIT_ULL(25); }
> >> +
> >> +static int amd_pstate_init_cpu(unsigned int cpunum) {
> >> + struct amd_cpudata *cpudata;
> >> +
> >> + cpudata = all_cpu_data[cpunum];
> >> + if (!cpudata) {
> >> + cpudata = kzalloc(sizeof(*cpudata), GFP_KERNEL);
> >> + if (!cpudata)
> >> + return -ENOMEM;
> >> + WRITE_ONCE(all_cpu_data[cpunum], cpudata);
> >> +
> >> + cpudata->cpu = cpunum;
> >> + }
> >> + cpudata->epp_powersave = -EINVAL;
> >> + cpudata->epp_policy = 0;
> >> + pr_debug("controlling: cpu %d\n", cpunum);
> >> + return 0;
> >> +}
> >> +
> >> +static int __amd_pstate_cpu_init(struct cpufreq_policy *policy) {
> >> + int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq,
> >> +ret;
> >> + struct amd_cpudata *cpudata;
> >> + struct device *dev;
> >> + int rc;
> >> + u64 value;
> >> +
> >> + rc = amd_pstate_init_cpu(policy->cpu);
> >> + if (rc)
> >> + return rc;
> >> +
> >> + cpudata = all_cpu_data[policy->cpu];
> >> +
> >> + dev = get_cpu_device(policy->cpu);
> >> + if (!dev)
> >> + goto free_cpudata1;
> >> +
> >> + rc = amd_pstate_init_perf(cpudata);
> >> + if (rc)
> >> + goto free_cpudata1;
> >> +
> >> + min_freq = amd_get_min_freq(cpudata);
> >> + max_freq = amd_get_max_freq(cpudata);
> >> + nominal_freq = amd_get_nominal_freq(cpudata);
> >> + lowest_nonlinear_freq = amd_get_lowest_nonlinear_freq(cpudata);
> >> + if (min_freq < 0 || max_freq < 0 || min_freq > max_freq) {
> >> + dev_err(dev, "min_freq(%d) or max_freq(%d) value is
> >> +incorrect\n",
> >> + min_freq, max_freq);
> >> + ret = -EINVAL;
> >> + goto free_cpudata1;
> >> + }
> >> +
> >> + policy->min = min_freq;
> >> + policy->max = max_freq;
> >> +
> >> + policy->cpuinfo.min_freq = min_freq;
> >> + policy->cpuinfo.max_freq = max_freq;
> >> + /* It will be updated by governor */
> >> + policy->cur = policy->cpuinfo.min_freq;
> >> +
> >> + /* Initial processor data capability frequencies */
> >> + cpudata->max_freq = max_freq;
> >> + cpudata->min_freq = min_freq;
> >> + cpudata->nominal_freq = nominal_freq;
> >> + cpudata->lowest_nonlinear_freq = lowest_nonlinear_freq;
> >> +
> >> + policy->driver_data = cpudata;
> >> +
> >> + update_boost_state();
> >> + cpudata->epp_cached = amd_pstate_get_epp(cpudata, value);
> >> +
> >> + policy->min = policy->cpuinfo.min_freq;
> >> + policy->max = policy->cpuinfo.max_freq;
> >> +
> >> + if (boot_cpu_has(X86_FEATURE_CPPC))
> >> + policy->fast_switch_possible = true;
> >> +
> >> + if (!shared_mem && boot_cpu_has(X86_FEATURE_CPPC)) {
> >> + ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, &value);
> >> + if (ret)
> >> + return ret;
> >> + WRITE_ONCE(cpudata->cppc_req_cached, value);
> >> +
> >> + ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1,
> >> +&value);
> >> + if (ret)
> >> + return ret;
> >> + WRITE_ONCE(cpudata->cppc_cap1_cached, value);
> >> + }
> >> + amd_pstate_boost_init(cpudata);
> >> +
> >> + return 0;
> >> +
> >> +free_cpudata1:
> >> + kfree(cpudata);
> >> + return ret;
> >> +}
> >> +
> >> +static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy) {
> >> + int ret;
> >> +
> >> + ret = __amd_pstate_cpu_init(policy);
> >> + if (ret)
> >> + return ret;
> >> + /*
> >> + * Set the policy to powersave to provide a valid fallback value
> >> +in case
> >> + * the default cpufreq governor is neither powersave nor performance.
> >> + */
> >> + policy->policy = CPUFREQ_POLICY_POWERSAVE;
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static int amd_pstate_epp_cpu_exit(struct cpufreq_policy *policy) {
> >> + pr_debug("amd-pstate: CPU %d exiting\n", policy->cpu);
> >
> > Drop the "amd-pstate:", this file has pr_fmt.
> >
> >> + policy->fast_switch_possible = false;
> >> + return 0;
> >> +}
> >> +
> >> +static void amd_pstate_update_max_freq(unsigned int cpu) {
> >> + struct cpufreq_policy *policy = policy = cpufreq_cpu_get(cpu);
> >> +
> >> + if (!policy)
> >> + return;
> >> +
> >> + refresh_frequency_limits(policy);
> >> + cpufreq_cpu_put(policy);
> >> +}
> >> +
> >> +static void amd_pstate_epp_update_limits(unsigned int cpu) {
> >> + mutex_lock(&amd_pstate_driver_lock);
> >> + update_boost_state();
> >> + if (global_params.cppc_boost_disabled) {
> >> + for_each_possible_cpu(cpu)
> >> + amd_pstate_update_max_freq(cpu);
> >> + } else {
> >> + cpufreq_update_policy(cpu);
> >> + }
> >> + mutex_unlock(&amd_pstate_driver_lock);
> >> +}
> >> +
> >> +static int cppc_boost_hold_time_ns = 3 * NSEC_PER_MSEC;
> >> +
> >> +static inline void amd_pstate_boost_up(struct amd_cpudata *cpudata)
> >> +{
> >> + u64 hwp_req = READ_ONCE(cpudata->cppc_req_cached);
> >> + u64 hwp_cap = READ_ONCE(cpudata->cppc_cap1_cached);
> >> + u32 max_limit = (hwp_req & 0xff);
> >> + u32 min_limit = (hwp_req & 0xff00) >> 8;
> >> + u32 boost_level1;
> >> +
> >> + /* If max and min are equal or already at max, nothing to boost
> >> +*/
> >> + if (max_limit == min_limit)
> >> + return;
> >> +
> >> + /* Set boost max and min to initial value */
> >> + if (!cpudata->cppc_boost_min)
> >> + cpudata->cppc_boost_min = min_limit;
> >> +
> >> + boost_level1 = ((AMD_CPPC_NOMINAL_PERF(hwp_cap) +
> min_limit) >>
> >> +1);
> >> +
> >> + if (cpudata->cppc_boost_min < boost_level1)
> >> + cpudata->cppc_boost_min = boost_level1;
> >> + else if (cpudata->cppc_boost_min <
> >> +AMD_CPPC_NOMINAL_PERF(hwp_cap))
> >> + cpudata->cppc_boost_min =
> AMD_CPPC_NOMINAL_PERF(hwp_cap);
> >> + else if (cpudata->cppc_boost_min ==
> >> +AMD_CPPC_NOMINAL_PERF(hwp_cap))
> >> + cpudata->cppc_boost_min = max_limit;
> >> + else
> >> + return;
> >> +
> >> + hwp_req &= ~AMD_CPPC_MIN_PERF(~0L);
> >> + hwp_req |= AMD_CPPC_MIN_PERF(cpudata->cppc_boost_min);
> >> + wrmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ,
> hwp_req);
> >> + cpudata->last_update = cpudata->sample.time; }
> >> +
> >> +static inline void amd_pstate_boost_down(struct amd_cpudata
> >> +*cpudata) {
> >> + bool expired;
> >> +
> >> + if (cpudata->cppc_boost_min) {
> >> + expired = time_after64(cpudata->sample.time,
> >> +cpudata->last_update +
> >> + cppc_boost_hold_time_ns);
> >> +
> >> + if (expired) {
> >> + wrmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ,
> >> + cpudata->cppc_req_cached);
> >> + cpudata->cppc_boost_min = 0;
> >> + }
> >> + }
> >> +
> >> + cpudata->last_update = cpudata->sample.time; }
> >> +
> >> +static inline void amd_pstate_boost_update_util(struct amd_cpudata
> >> +*cpudata,
> >> + u64 time) {
> >> + cpudata->sample.time = time;
> >> + if (smp_processor_id() != cpudata->cpu)
> >> + return;
> >> +
> >> + if (cpudata->sched_flags & SCHED_CPUFREQ_IOWAIT) {
> >> + bool do_io = false;
> >> +
> >> + cpudata->sched_flags = 0;
> >> + /*
> >> + * Set iowait_boost flag and update time. Since IO WAIT flag
> >> + * is set all the time, we can't just conclude that there is
> >> + * some IO bound activity is scheduled on this CPU with just
> >> + * one occurrence. If we receive at least two in two
> >> + * consecutive ticks, then we treat as boost candidate.
> >> + * This is leveraged from Intel Pstate driver.
> >> + */
> >> + if (time_before64(time, cpudata->last_io_update + 2 *
> >> +TICK_NSEC))
> >> + do_io = true;
> >> +
> >> + cpudata->last_io_update = time;
> >> +
> >> + if (do_io)
> >> + amd_pstate_boost_up(cpudata);
> >> +
> >> + } else {
> >> + amd_pstate_boost_down(cpudata);
> >> + }
> >> +}
> >> +
> >> +static inline void amd_pstate_cppc_update_hook(struct
> >> +update_util_data *data,
> >> + u64 time, unsigned int flags) {
> >> + struct amd_cpudata *cpudata = container_of(data,
> >> + struct amd_cpudata, update_util);
> >> +
> >> + cpudata->sched_flags |= flags;
> >> +
> >> + if (smp_processor_id() == cpudata->cpu)
> >> + amd_pstate_boost_update_util(cpudata, time); }
> >> +
> >> +static void amd_pstate_clear_update_util_hook(unsigned int cpu) {
> >> + struct amd_cpudata *cpudata = all_cpu_data[cpu];
> >> +
> >> + if (!cpudata->update_util_set)
> >> + return;
> >> +
> >> + cpufreq_remove_update_util_hook(cpu);
> >> + cpudata->update_util_set = false;
> >> + synchronize_rcu();
> >> +}
> >> +
> >> +static void amd_pstate_set_update_util_hook(unsigned int cpu_num) {
> >> + struct amd_cpudata *cpudata = all_cpu_data[cpu_num];
> >> +
> >> + if (!cppc_boost) {
> >> + if (cpudata->update_util_set)
> >> + amd_pstate_clear_update_util_hook(cpudata->cpu);
> >> + return;
> >> + }
> >> +
> >> + if (cpudata->update_util_set)
> >> + return;
> >> +
> >> + cpudata->sample.time = 0;
> >> + cpufreq_add_update_util_hook(cpu_num, &cpudata->update_util,
> >> + amd_pstate_cppc_update_hook);
> >> + cpudata->update_util_set = true; }
> >> +
> >> +static void amd_pstate_epp_init(unsigned int cpu) {
> >> + struct amd_cpudata *cpudata = all_cpu_data[cpu];
> >> + u32 max_perf, min_perf;
> >> + u64 value;
> >> + s16 epp;
> >> + int ret;
> >> +
> >> + max_perf = READ_ONCE(cpudata->highest_perf);
> >> + min_perf = READ_ONCE(cpudata->lowest_perf);
> >> +
> >> + value = READ_ONCE(cpudata->cppc_req_cached);
> >> +
> >> + if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
> >> + min_perf = max_perf;
> >> +
> >> + /* Initial min/max values for CPPC Performance Controls Register
> >> +*/
> >> + value &= ~AMD_CPPC_MIN_PERF(~0L);
> >> + value |= AMD_CPPC_MIN_PERF(min_perf);
> >> +
> >> + value &= ~AMD_CPPC_MAX_PERF(~0L);
> >> + value |= AMD_CPPC_MAX_PERF(max_perf);
> >> +
> >> + /* CPPC EPP feature require to set zero to the desire perf bit
> >> +*/
> >> + value &= ~AMD_CPPC_DES_PERF(~0L);
> >> + value |= AMD_CPPC_DES_PERF(0);
> >> +
> >> + if (cpudata->epp_policy == cpudata->policy)
> >> + goto skip_epp;
> >> +
> >> + cpudata->epp_policy = cpudata->policy;
> >> +
> >> + if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
> >> + epp = amd_pstate_get_epp(cpudata, value);
> >> + cpudata->epp_powersave = epp;
> >> + if (epp < 0)
> >> + goto skip_epp;
> >> + /* force the epp value to be zero for performance policy */
> >> + epp = 0;
> >> + } else {
> >> + if (cpudata->epp_powersave < 0)
> >> + goto skip_epp;
> >> + /* Get BIOS pre-defined epp value */
> >> + epp = amd_pstate_get_epp(cpudata, value);
> >> + if (epp)
> >> + goto skip_epp;
> >> + epp = cpudata->epp_powersave;
> >> + }
> >> + /* Set initial EPP value */
> >> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
> >> + value &= ~GENMASK_ULL(31, 24);
> >> + value |= (u64)epp << 24;
> >> + }
> >> +
> >> +skip_epp:
> >> + WRITE_ONCE(cpudata->cppc_req_cached, value);
> >> + ret = wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
> >> + if (!ret)
> >> + cpudata->epp_cached = epp;
> >> +}
> >> +
> >> +static void amd_pstate_set_max_limits(struct amd_cpudata *cpudata) {
> >> + u64 hwp_cap = READ_ONCE(cpudata->cppc_cap1_cached);
> >> + u64 hwp_req = READ_ONCE(cpudata->cppc_req_cached);
> >> + u32 max_limit = (hwp_cap >> 24) & 0xff;
> >> +
> >> + hwp_req &= ~AMD_CPPC_MIN_PERF(~0L);
> >> + hwp_req |= AMD_CPPC_MIN_PERF(max_limit);
> >> + wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, hwp_req); }
> >> +
> >> +static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
> >> +{
> >> + struct amd_cpudata *cpudata;
> >> +
> >> + if (!policy->cpuinfo.max_freq)
> >> + return -ENODEV;
> >> +
> >> + pr_debug("set_policy: cpuinfo.max %u policy->max %u\n",
> >> + policy->cpuinfo.max_freq, policy->max);
> >> +
> >> + cpudata = all_cpu_data[policy->cpu];
> >> + cpudata->policy = policy->policy;
> >> +
> >> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
> >> + mutex_lock(&amd_pstate_limits_lock);
> >> +
> >> + if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
> >> + amd_pstate_clear_update_util_hook(policy->cpu);
> >> + amd_pstate_set_max_limits(cpudata);
> >> + } else {
> >> + amd_pstate_set_update_util_hook(policy->cpu);
> >> + }
> >> +
> >> + if (boot_cpu_has(X86_FEATURE_CPPC))
> >> + amd_pstate_epp_init(policy->cpu);
> >> +
> >> + mutex_unlock(&amd_pstate_limits_lock);
> >> + }
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static void amd_pstate_verify_cpu_policy(struct amd_cpudata
> >> +*cpudata,
> >> + struct cpufreq_policy_data *policy) {
> >> + update_boost_state();
> >> + cpufreq_verify_within_cpu_limits(policy);
> >> +}
> >> +
> >> +static int amd_pstate_epp_verify_policy(struct cpufreq_policy_data
> >> +*policy) {
> >> + amd_pstate_verify_cpu_policy(all_cpu_data[policy->cpu], policy);
> >> + pr_debug("policy_max =%d, policy_min=%d\n", policy->max,
> >> +policy->min);
> >> + return 0;
> >> +}
> >> +
> >> static struct cpufreq_driver amd_pstate_driver = {
> >> .flags = CPUFREQ_CONST_LOOPS |
> >> CPUFREQ_NEED_UPDATE_LIMITS,
> >> .verify = amd_pstate_verify, @@ -607,8 +1222,20 @@
> >> static struct cpufreq_driver amd_pstate_driver = {
> >> .attr = amd_pstate_attr,
> >> };
> >> +static struct cpufreq_driver amd_pstate_epp_driver = {
> >> + .flags = CPUFREQ_CONST_LOOPS,
> >> + .verify = amd_pstate_epp_verify_policy,
> >> + .setpolicy = amd_pstate_epp_set_policy,
> >> + .init = amd_pstate_epp_cpu_init,
> >> + .exit = amd_pstate_epp_cpu_exit,
> >> + .update_limits = amd_pstate_epp_update_limits,
> >> + .name = "amd_pstate_epp",
> >> + .attr = amd_pstate_epp_attr, };
> >> +
> >> static int __init amd_pstate_init(void)
> >> {
> >> + static struct amd_cpudata **cpudata;
> >> int ret;
> >> if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) @@ -623,10
> >> +1250,18 @@ static int __init amd_pstate_init(void)
> >> if (cpufreq_get_current_driver())
> >> return -EEXIST;
> >> + if (!epp_off) {
> >> + WRITE_ONCE(cppc_active, 1);
> >> + if (!default_pstate_driver)
> >> + default_pstate_driver = &amd_pstate_epp_driver;
> >> + }
> >> + pr_info("AMD CPPC loading with %s driver instance.\n",
> >> +default_pstate_driver->name);
> >
> > This is pretty noisy, do we really need it on every boot if we can easily
> check it from sysfs?
> >
> >> +
> >> /* capability check */
> >> if (boot_cpu_has(X86_FEATURE_CPPC)) {
> >> + if (!cppc_active)
> >> + default_pstate_driver->adjust_perf =
> >> +amd_pstate_adjust_perf;
> >> pr_debug("AMD CPPC MSR based functionality is
> >> supported\n");
> >> - amd_pstate_driver.adjust_perf = amd_pstate_adjust_perf;
> >> } else if (shared_mem) {
> >> static_call_update(amd_pstate_enable, cppc_enable);
> >> static_call_update(amd_pstate_init_perf, cppc_init_perf);
> >> @@ -636,6 +1271,10 @@ static int __init amd_pstate_init(void)
> >> return -ENODEV;
> >> }
> >> + cpudata = vzalloc(array_size(sizeof(void *),
> >> num_possible_cpus()));
> >> + if (!cpudata)
> >> + return -ENOMEM;
> >> + WRITE_ONCE(all_cpu_data, cpudata);
> >> /* enable amd pstate feature */
> >> ret = amd_pstate_enable(true);
> >> if (ret) {
> >> @@ -643,9 +1282,9 @@ static int __init amd_pstate_init(void)
> >> return ret;
> >> }
> >> - ret = cpufreq_register_driver(&amd_pstate_driver);
> >> + ret = cpufreq_register_driver(default_pstate_driver);
> >> if (ret)
> >> - pr_err("failed to register amd_pstate_driver with return
> >> %d\n",
> >> + pr_err("failed to register amd pstate driver with return
> >> +%d\n",
> >> ret);
> >> return ret;
> >> @@ -657,6 +1296,15 @@ static int __init amd_pstate_param(char *str)
> >> if (!str)
> >> return -EINVAL;
> >> + if (!strcmp(str, "disable"))
> >> + disable_pstate_load = 1;
> >> + else if (!strcmp(str, "active")) {
> >> + default_pstate_driver = &amd_pstate_epp_driver;
> >> + } else if (!strcmp(str, "passive")) {
> >> + epp_off = 1;
> >> + default_pstate_driver = &amd_pstate_driver;
> >> + }
> >> +
> >> /* enable shared memory type CPPC ,if you processor has no MSR,
> >> you have to add this
> >> * to your grub to make cppc driver loaded successfully.
> >> */
> >> diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
> >> index 1c4b8659f171..7e6e8cab97b3 100644
> >> --- a/include/linux/amd-pstate.h
> >> +++ b/include/linux/amd-pstate.h
> >> @@ -25,6 +25,7 @@ struct amd_aperf_mperf {
> >> u64 aperf;
> >> u64 mperf;
> >> u64 tsc;
> >> + u64 time;
> >> };
> >> /**
> >> @@ -47,6 +48,18 @@ struct amd_aperf_mperf {
> >> * @prev: Last Aperf/Mperf/tsc count value read from register
> >> * @freq: current cpu frequency value
> >> * @boost_supported: check whether the Processor or SBIOS supports
> >> boost mode
> >> + * @epp_powersave: Last saved CPPC energy performance preference
> >> + when policy switched to performance
> >> + * @epp_policy: Last saved policy used to set energy-performance
> >> +preference
> >> + * @epp_cached: Cached CPPC energy-performance preference value
> >> + * @policy: Cpufreq policy value
> >> + * @sched_flags: Store scheduler flags for possible cross CPU update
> >> + * @update_util_set: CPUFreq utility callback is set
> >> + * @last_update: Time stamp of the last performance state update
> >> + * @cppc_boost_min: Last CPPC boosted min performance state
> >> + * @cppc_cap1_cached: Cached value of the last CPPC Capabilities MSR
> >> + * @update_util: Cpufreq utility callback information
> >> + * @sample: the stored performance sample
> >> *
> >> * The amd_cpudata is key private data for each CPU thread in AMD
> >> P-State, and
> >> * represents all the attributes and goals that AMD P-State requests at
> runtime.
> >> @@ -72,6 +85,74 @@ struct amd_cpudata {
> >> u64 freq;
> >> bool boost_supported;
> >> +
> >> + /* EPP feature related attributes*/
> >> + s16 epp_powersave;
> >> + s16 epp_policy;
> >> + s16 epp_cached;
> >> + u32 policy;
> >> + u32 sched_flags;
> >> + bool update_util_set;
> >> + u64 last_update;
> >> + u64 last_io_update;
> >> + u32 cppc_boost_min;
> >> + u64 cppc_cap1_cached;
> >> + struct update_util_data update_util;
> >> + struct amd_aperf_mperf sample; };
> >> +
> >> +/**
> >> + * struct amd_pstate_params - global parameters for the performance
> >> +control
> >> + * @ cppc_boost_disabled wheher the core performance boost disabled
> >> +*/ struct amd_pstate_params {
> >> + bool cppc_boost_disabled;
> >> +};
> >> +
> >> +#define AMD_CPPC_EPP_PERFORMANCE 0x00 #define
> >> +AMD_CPPC_EPP_BALANCE_PERFORMANCE 0x80 #define
> >> +AMD_CPPC_EPP_BALANCE_POWERSAVE 0xBF #define
> >> +AMD_CPPC_EPP_POWERSAVE 0xFF
> >> +
> >> +/*
> >> + * AMD Energy Preference Performance (EPP)
> >> + * The EPP is used in the CCLK DPM controller to drive
> >> + * the frequency that a core is going to operate during
> >> + * short periods of activity. EPP values will be utilized for
> >> + * different OS profiles (balanced, performance, power savings)
> >> + * display strings corresponding to EPP index in the
> >> + * energy_perf_strings[]
> >> + * index String
> >> + *-------------------------------------
> >> + * 0 default
> >> + * 1 performance
> >> + * 2 balance_performance
> >> + * 3 balance_power
> >> + * 4 power
> >> + */
> >> +enum energy_perf_value_index {
> >> + EPP_INDEX_DEFAULT = 0,
> >> + EPP_INDEX_PERFORMANCE,
> >> + EPP_INDEX_BALANCE_PERFORMANCE,
> >> + EPP_INDEX_BALANCE_POWERSAVE,
> >> + EPP_INDEX_POWERSAVE,
> >> +};
> >> +
> >> +static const char * const energy_perf_strings[] = {
> >> + [EPP_INDEX_DEFAULT] = "default",
> >> + [EPP_INDEX_PERFORMANCE] = "performance",
> >> + [EPP_INDEX_BALANCE_PERFORMANCE] = "balance_performance",
> >> + [EPP_INDEX_BALANCE_POWERSAVE] = "balance_power",
> >> + [EPP_INDEX_POWERSAVE] = "power",
> >> + NULL
> >> +};
> >> +
> >> +static unsigned int epp_values[] = {
> >> + [EPP_INDEX_DEFAULT] = 0,
> >> + [EPP_INDEX_PERFORMANCE] = AMD_CPPC_EPP_PERFORMANCE,
> >> + [EPP_INDEX_BALANCE_PERFORMANCE] =
> >> +AMD_CPPC_EPP_BALANCE_PERFORMANCE,
> >> + [EPP_INDEX_BALANCE_POWERSAVE] =
> AMD_CPPC_EPP_BALANCE_POWERSAVE,
> >> + [EPP_INDEX_POWERSAVE] = AMD_CPPC_EPP_POWERSAVE,
> >> };
> >> #endif /* _LINUX_AMD_PSTATE_H */
> >
[AMD Official Use Only - General]
Hi Nathan.
> -----Original Message-----
> From: Fontenot, Nathan <[email protected]>
> Sent: Friday, November 11, 2022 12:07 AM
> To: Yuan, Perry <[email protected]>; [email protected]; Huang,
> Ray <[email protected]>; [email protected]
> Cc: Sharma, Deepak <[email protected]>; Limonciello, Mario
> <[email protected]>; Deucher, Alexander
> <[email protected]>; Huang, Shimmer
> <[email protected]>; Du, Xiaojian <[email protected]>; Meng,
> Li (Jassmine) <[email protected]>; [email protected]; linux-
> [email protected]
> Subject: Re: [PATCH v3 8/8] cpufreq: amd_pstate: add driver working mode
> status sysfs entry
>
> On 11/7/22 11:57, Perry Yuan wrote:
> > While amd-pstate driver was loaded with specific driver mode, it will
> > need to check which mode is enabled for the pstate driver,add this
> > sysfs entry to show the current status
> >
> > $ cat /sys/devices/system/cpu/amd-pstate/status
> > active
> >
> > Signed-off-by: Perry Yuan <[email protected]>
> > ---
> > drivers/cpufreq/amd-pstate.c | 44
> > ++++++++++++++++++++++++++++++++++++
> > 1 file changed, 44 insertions(+)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 6958c5fd9e1c..eadcc9d61d39 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -65,6 +65,8 @@ static int disable_pstate_load __initdata; static
> > int epp_off __initdata;
> >
> > static struct cpufreq_driver *default_pstate_driver;
> > +static struct cpufreq_driver amd_pstate_epp_driver; static struct
> > +cpufreq_driver amd_pstate_driver;
> > static struct amd_cpudata **all_cpu_data;
> >
> > static struct amd_pstate_params global_params; @@ -819,6 +821,46 @@
> > static ssize_t store_pstate_dynamic_boost(struct kobject *a,
> > return count;
> > }
> >
> > +static ssize_t amd_pstate_show_status(char *buf) {
> > + if (!default_pstate_driver)
> > + return sprintf(buf, "off\n");
> > +
> > + return sprintf(buf, "%s\n", default_pstate_driver ==
> &amd_pstate_epp_driver ?
> > + "active" : "passive");
> > +}
> > +
> > +static int amd_pstate_update_status(const char *buf, size_t size) {
> > + /* FIXME: add driver dynamic switching code */
> > + return 0;
> > +}
> > +
> > +static ssize_t show_status(struct kobject *kobj,
> > + struct kobj_attribute *attr, char *buf) {
> > + ssize_t ret;
> > +
> > + mutex_lock(&amd_pstate_driver_lock);
> > + ret = amd_pstate_show_status(buf);
> > + mutex_unlock(&amd_pstate_driver_lock);
>
> Do we really need to take a lock to show the driver status?
Yes.
It needs to check the current status from sysfs now and it will support to switch the EPP and Non EPP driver through this sysfs node.
Perry.
>
> -Nathan
>
> > +
> > + return ret;
> > +}
> > +
> > +static ssize_t store_status(struct kobject *a, struct kobj_attribute *b,
> > + const char *buf, size_t count) {
> > + char *p = memchr(buf, '\n', count);
> > + int ret;
> > +
> > + mutex_lock(&amd_pstate_driver_lock);
> > + ret = amd_pstate_update_status(buf, p ? p - buf : count);
> > + mutex_unlock(&amd_pstate_driver_lock);
> > +
> > + return ret < 0 ? ret : count;
> > +}
> > +
> > cpufreq_freq_attr_ro(amd_pstate_max_freq);
> > cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
> >
> > @@ -826,6 +868,7 @@ cpufreq_freq_attr_ro(amd_pstate_highest_perf);
> > cpufreq_freq_attr_rw(energy_performance_preference);
> > cpufreq_freq_attr_ro(energy_performance_available_preferences);
> > define_one_global_rw(pstate_dynamic_boost);
> > +define_one_global_rw(status);
> >
> > static struct freq_attr *amd_pstate_attr[] = {
> > &amd_pstate_max_freq,
> > @@ -845,6 +888,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
> >
> > static struct attribute *pstate_global_attributes[] = {
> > &pstate_dynamic_boost.attr,
> > + &status.attr,
> > NULL
> > };
> >
On 11/7/22 14:32, Limonciello, Mario wrote:
> On 11/7/2022 11:57, Perry Yuan wrote:
>> Add EPP driver support for those AMD CPUs which has full MSR feature
>> enabled, The EPP is used in the DPM controller to drive the frequency
>> that a core is going to operate during short periods of activity.
>
> To avoid the run on sentence, here is a different wording proposal.
>
> Add EPP driver support for AMD SoCs which support a dedicated MSR for CPPC. EPP is used by the DPM controller to configure the frequency that a core operates at during short periods of activity.
>
>>
>> EPP values will be utilized for different OS profiles (balanced, performance,
>> power savings). cppc performance can be controlled by the user space interface
>> sys attributes for min and max frequency limits, when pstate driver is
>> working under power save policy.
>>
>> EPP scale is 0 - 255, 0 is the max performance and 255 is min level.
>> balance_performance (0x80) can provide best balance performance and watt for
>> most of system, meanwhile user can choose performance policy on needs.
>
> As a user reading this message it is confusing that there are values and then there are strings, but you don't know the linkage between the two. My proposal for rewording this:
>
> The SoC EPP targets are configured on a scale from 0 to 255 where 0 represents maximum performance and 255 represents maximum efficiency.
>
> The amd-pstate driver exports profile string names to userspace that are tied to specific EPP values.
>
> The balance_performance string (0x80) provides the best balance for efficiency versus power on most systems, but users can choose other strings to meet their needs as well.
>
>>
>> $ cat /sys/devices/system/cpu/cpufreq/policy0/energy_performance_available_preferences
>> default performance balance_performance balance_power power
>>
>> $ cat /sys/devices/system/cpu/cpufreq/policy0/energy_performance_preference
>> balance_performance
>>
>> Signed-off-by: Perry Yuan <[email protected]>
>> ---
>> drivers/cpufreq/amd-pstate.c | 658 ++++++++++++++++++++++++++++++++++-
>> include/linux/amd-pstate.h | 81 +++++
>> 2 files changed, 734 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
>> index 14906431dc15..eb82bc6a7f66 100644
>> --- a/drivers/cpufreq/amd-pstate.c
>> +++ b/drivers/cpufreq/amd-pstate.c
>> @@ -60,8 +60,136 @@
>> * module parameter to be able to enable it manually for debugging.
>> */
>> static bool shared_mem __read_mostly;
>> +static int cppc_active __read_mostly;
>> +static int disable_pstate_load __initdata;
>> +static int epp_off __initdata;
>> -static struct cpufreq_driver amd_pstate_driver;
>> +static struct cpufreq_driver *default_pstate_driver;
>> +static struct amd_cpudata **all_cpu_data;
>> +
>> +static struct amd_pstate_params global_params;
>> +
>> +static DEFINE_MUTEX(amd_pstate_limits_lock);
>> +static DEFINE_MUTEX(amd_pstate_driver_lock);
>> +
>> +static bool cppc_boost __read_mostly;
>> +struct kobject *amd_pstate_kobj;
>> +
>> +#ifdef CONFIG_ACPI_CPPC_LIB
>> +static s16 amd_pstate_get_epp(struct amd_cpudata *cpudata, u64 cppc_req_cached)
>> +{
>> + s16 epp;
>> + struct cppc_perf_caps perf_caps;
>> + int ret;
>> +
>> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
>> + if (!cppc_req_cached) {
>> + epp = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ,
>> + &cppc_req_cached);
>> + if (epp)
>> + return epp;
>> + }
>> + epp = (cppc_req_cached >> 24) & 0xFF;
>> + } else {
>> + ret = cppc_get_epp_caps(cpudata->cpu, &perf_caps);
>> + if (ret < 0) {
>> + pr_debug("Could not retrieve energy perf value (%d)\n", ret);
>> + return -EIO;
>> + }
>> + epp = (s16) perf_caps.energy_perf;
>> + }
>> +
>> + return epp;
>> +}
>> +#endif
>> +
>> +static int amd_pstate_get_energy_pref_index(struct amd_cpudata *cpudata, int *raw_epp)
>> +{
>> + s16 epp;
>> + int index = -EINVAL;
>> +
>> + *raw_epp = 0;
>> + epp = amd_pstate_get_epp(cpudata, 0);
>> + if (epp < 0)
>> + return epp;
>> +
>> + switch (epp) {
>> + case AMD_CPPC_EPP_PERFORMANCE:
>> + index = EPP_INDEX_PERFORMANCE;
>> + break;
>> + case AMD_CPPC_EPP_BALANCE_PERFORMANCE:
>> + index = EPP_INDEX_BALANCE_PERFORMANCE;
>> + break;
>> + case AMD_CPPC_EPP_BALANCE_POWERSAVE:
>> + index = EPP_INDEX_BALANCE_POWERSAVE;
>> + break;
>> + case AMD_CPPC_EPP_POWERSAVE:
>> + index = EPP_INDEX_POWERSAVE;
>> + break;
>> + default:
>> + *raw_epp = epp;
>> + index = 0;
>> + }
>> +
>> + return index;
>> +}
>> +
>> +#ifdef CONFIG_ACPI_CPPC_LIB
>> +static int amd_pstate_set_epp(struct amd_cpudata *cpudata, u32 epp)
>> +{
>> + int ret;
>> + struct cppc_perf_ctrls perf_ctrls;
>> +
>> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
>> + u64 value = READ_ONCE(cpudata->cppc_req_cached);
>> +
>> + value &= ~GENMASK_ULL(31, 24);
>> + value |= (u64)epp << 24;
>> + WRITE_ONCE(cpudata->cppc_req_cached, value);
>> +
>> + ret = wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
>> + if (!ret)
>> + cpudata->epp_cached = epp;
>> + } else {
>> + perf_ctrls.energy_perf = epp;
>> + ret = cppc_set_epp_perf(cpudata->cpu, &perf_ctrls);
>> + if (ret) {
>> + pr_debug("failed to set energy perf value (%d)\n", ret);
>> + return ret;
>> + }
>> + cpudata->epp_cached = epp;
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +static int amd_pstate_set_energy_pref_index(struct amd_cpudata *cpudata,
>> + int pref_index, bool use_raw,
>> + u32 raw_epp)
>> +{
>> + int epp = -EINVAL;
>> + int ret;
>> +
>> + if (!pref_index) {
>> + pr_debug("EPP pref_index is invalid\n");
>> + return -EINVAL;
>> + }
>> +
>> + if (use_raw)
>> + epp = raw_epp;
>> + else if (epp == -EINVAL)
>> + epp = epp_values[pref_index];
>> +
>> + if (epp > 0 && cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
>> + pr_debug("EPP cannot be set under performance policy\n");
>> + return -EBUSY;
>> + }
>> +
>> + ret = amd_pstate_set_epp(cpudata, epp);
>> +
>> + return ret;
>> +}
>> +#endif
>> static inline int pstate_enable(bool enable)
>> {
>> @@ -71,11 +199,25 @@ static inline int pstate_enable(bool enable)
>> static int cppc_enable(bool enable)
>> {
>> int cpu, ret = 0;
>> + struct cppc_perf_ctrls perf_ctrls;
>> for_each_present_cpu(cpu) {
>> ret = cppc_set_enable(cpu, enable);
>> if (ret)
>> return ret;
>> +
>> + /* Enable autonomous mode for EPP */
>> + if (!cppc_active) {
>> + ret = cppc_set_auto_epp(cpu, enable);
>> + if (ret)
>> + return ret;
>> +
>> + /* Set desired perf as zero to allow EPP firmware control */
>> + perf_ctrls.desired_perf = 0;
>> + ret = cppc_set_perf(cpu, &perf_ctrls);
>> + if (ret)
>> + return ret;
>> + }
>> }
>> return ret;
>> @@ -418,7 +560,7 @@ static void amd_pstate_boost_init(struct amd_cpudata *cpudata)
>> return;
>> cpudata->boost_supported = true;
>> - amd_pstate_driver.boost_enabled = true;
>> + default_pstate_driver->boost_enabled = true;
>> }
>> static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
>> @@ -582,10 +724,74 @@ static ssize_t show_amd_pstate_highest_perf(struct cpufreq_policy *policy,
>> return sprintf(&buf[0], "%u\n", perf);
>> }
>> +static ssize_t show_energy_performance_available_preferences(
>> + struct cpufreq_policy *policy, char *buf)
>> +{
>> + int i = 0;
>> + int ret = 0;
>> +
>> + while (energy_perf_strings[i] != NULL)
>> + ret += sprintf(&buf[ret], "%s ", energy_perf_strings[i++]);
>> +
>> + ret += sprintf(&buf[ret], "\n");
>> +
>> + return ret;
>> +}
>> +
>> +static ssize_t store_energy_performance_preference(
>> + struct cpufreq_policy *policy, const char *buf, size_t count)
>> +{
>> + struct amd_cpudata *cpudata = policy->driver_data;
>> + char str_preference[21];
>> + bool raw = false;
>> + ssize_t ret;
>> + u32 epp = 0;
>> +
>> + ret = sscanf(buf, "%20s", str_preference);
>> + if (ret != 1)
>> + return -EINVAL;
>> +
>> + ret = match_string(energy_perf_strings, -1, str_preference);
>> + if (ret < 0) {
>> + ret = kstrtouint(buf, 10, &epp);
>> + if (ret)
>> + return ret;
>> +
>> + if ((epp > 255) || (epp < 0))
>> + return -EINVAL;
>> +
>> + raw = true;
>> + }
>
> What's the reason for supporting putting the raw number in here for stuff "in between"? I think this is going to pretty confusing to userspace that you can use string values or integer values. It also means that if userspace writes an integer with a mapping to string and tries to read it back they'll get the string rather than the integer!
>
> I can understand using the raw values for internal characterization and development to possibly introduce a new mapping string, but I don't think that makes sense in the kernel.
>
This is really doing what Intel does for handling EPP settings. Yes, writing a value and getting back a string
could be a bit confusing bit it is already done from the Intel side. I think keeping EPP value setting common
would be a good thing if we can do it.
I don't think we should remove the ability to set raw values, we're allowed a range of 0 - 255 for the EPP
setting. Why we then limit ourselves to only 4 or so values?
-Nathan
>> +
>> + mutex_lock(&amd_pstate_limits_lock);
>> + ret = amd_pstate_set_energy_pref_index(cpudata, ret, raw, epp);
>> + mutex_unlock(&amd_pstate_limits_lock);
>> +
>> + return ret ?: count;
>> +}
>> +
>> +static ssize_t show_energy_performance_preference(
>> + struct cpufreq_policy *policy, char *buf)
>> +{
>> + struct amd_cpudata *cpudata = policy->driver_data;
>> + int preference, raw_epp;
>> +
>> + preference = amd_pstate_get_energy_pref_index(cpudata, &raw_epp);
>> + if (preference < 0)
>> + return preference;
>> +
>> + if (raw_epp)
>> + return sprintf(buf, "%d\n", raw_epp);
>> + else
>> + return sprintf(buf, "%s\n", energy_perf_strings[preference]);
>> +}
>> +
>> cpufreq_freq_attr_ro(amd_pstate_max_freq);
>> cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
>> cpufreq_freq_attr_ro(amd_pstate_highest_perf);
>> +cpufreq_freq_attr_rw(energy_performance_preference);
>> +cpufreq_freq_attr_ro(energy_performance_available_preferences);
>> static struct freq_attr *amd_pstate_attr[] = {
>> &amd_pstate_max_freq,
>> @@ -594,6 +800,415 @@ static struct freq_attr *amd_pstate_attr[] = {
>> NULL,
>> };
>> +static struct freq_attr *amd_pstate_epp_attr[] = {
>> + &amd_pstate_max_freq,
>> + &amd_pstate_lowest_nonlinear_freq,
>> + &amd_pstate_highest_perf,
>> + &energy_performance_preference,
>> + &energy_performance_available_preferences,
>> + NULL,
>> +};
>> +
>> +static inline void update_boost_state(void)
>> +{
>> + u64 misc_en;
>> + struct amd_cpudata *cpudata;
>> +
>> + cpudata = all_cpu_data[0];
>> + rdmsrl(MSR_K7_HWCR, misc_en);
>> + global_params.cppc_boost_disabled = misc_en & BIT_ULL(25);
>> +}
>> +
>> +static int amd_pstate_init_cpu(unsigned int cpunum)
>> +{
>> + struct amd_cpudata *cpudata;
>> +
>> + cpudata = all_cpu_data[cpunum];
>> + if (!cpudata) {
>> + cpudata = kzalloc(sizeof(*cpudata), GFP_KERNEL);
>> + if (!cpudata)
>> + return -ENOMEM;
>> + WRITE_ONCE(all_cpu_data[cpunum], cpudata);
>> +
>> + cpudata->cpu = cpunum;
>> + }
>> + cpudata->epp_powersave = -EINVAL;
>> + cpudata->epp_policy = 0;
>> + pr_debug("controlling: cpu %d\n", cpunum);
>> + return 0;
>> +}
>> +
>> +static int __amd_pstate_cpu_init(struct cpufreq_policy *policy)
>> +{
>> + int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
>> + struct amd_cpudata *cpudata;
>> + struct device *dev;
>> + int rc;
>> + u64 value;
>> +
>> + rc = amd_pstate_init_cpu(policy->cpu);
>> + if (rc)
>> + return rc;
>> +
>> + cpudata = all_cpu_data[policy->cpu];
>> +
>> + dev = get_cpu_device(policy->cpu);
>> + if (!dev)
>> + goto free_cpudata1;
>> +
>> + rc = amd_pstate_init_perf(cpudata);
>> + if (rc)
>> + goto free_cpudata1;
>> +
>> + min_freq = amd_get_min_freq(cpudata);
>> + max_freq = amd_get_max_freq(cpudata);
>> + nominal_freq = amd_get_nominal_freq(cpudata);
>> + lowest_nonlinear_freq = amd_get_lowest_nonlinear_freq(cpudata);
>> + if (min_freq < 0 || max_freq < 0 || min_freq > max_freq) {
>> + dev_err(dev, "min_freq(%d) or max_freq(%d) value is incorrect\n",
>> + min_freq, max_freq);
>> + ret = -EINVAL;
>> + goto free_cpudata1;
>> + }
>> +
>> + policy->min = min_freq;
>> + policy->max = max_freq;
>> +
>> + policy->cpuinfo.min_freq = min_freq;
>> + policy->cpuinfo.max_freq = max_freq;
>> + /* It will be updated by governor */
>> + policy->cur = policy->cpuinfo.min_freq;
>> +
>> + /* Initial processor data capability frequencies */
>> + cpudata->max_freq = max_freq;
>> + cpudata->min_freq = min_freq;
>> + cpudata->nominal_freq = nominal_freq;
>> + cpudata->lowest_nonlinear_freq = lowest_nonlinear_freq;
>> +
>> + policy->driver_data = cpudata;
>> +
>> + update_boost_state();
>> + cpudata->epp_cached = amd_pstate_get_epp(cpudata, value);
>> +
>> + policy->min = policy->cpuinfo.min_freq;
>> + policy->max = policy->cpuinfo.max_freq;
>> +
>> + if (boot_cpu_has(X86_FEATURE_CPPC))
>> + policy->fast_switch_possible = true;
>> +
>> + if (!shared_mem && boot_cpu_has(X86_FEATURE_CPPC)) {
>> + ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, &value);
>> + if (ret)
>> + return ret;
>> + WRITE_ONCE(cpudata->cppc_req_cached, value);
>> +
>> + ret = rdmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_CAP1, &value);
>> + if (ret)
>> + return ret;
>> + WRITE_ONCE(cpudata->cppc_cap1_cached, value);
>> + }
>> + amd_pstate_boost_init(cpudata);
>> +
>> + return 0;
>> +
>> +free_cpudata1:
>> + kfree(cpudata);
>> + return ret;
>> +}
>> +
>> +static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
>> +{
>> + int ret;
>> +
>> + ret = __amd_pstate_cpu_init(policy);
>> + if (ret)
>> + return ret;
>> + /*
>> + * Set the policy to powersave to provide a valid fallback value in case
>> + * the default cpufreq governor is neither powersave nor performance.
>> + */
>> + policy->policy = CPUFREQ_POLICY_POWERSAVE;
>> +
>> + return 0;
>> +}
>> +
>> +static int amd_pstate_epp_cpu_exit(struct cpufreq_policy *policy)
>> +{
>> + pr_debug("amd-pstate: CPU %d exiting\n", policy->cpu);
>
> Drop the "amd-pstate:", this file has pr_fmt.
>
>> + policy->fast_switch_possible = false;
>> + return 0;
>> +}
>> +
>> +static void amd_pstate_update_max_freq(unsigned int cpu)
>> +{
>> + struct cpufreq_policy *policy = policy = cpufreq_cpu_get(cpu);
>> +
>> + if (!policy)
>> + return;
>> +
>> + refresh_frequency_limits(policy);
>> + cpufreq_cpu_put(policy);
>> +}
>> +
>> +static void amd_pstate_epp_update_limits(unsigned int cpu)
>> +{
>> + mutex_lock(&amd_pstate_driver_lock);
>> + update_boost_state();
>> + if (global_params.cppc_boost_disabled) {
>> + for_each_possible_cpu(cpu)
>> + amd_pstate_update_max_freq(cpu);
>> + } else {
>> + cpufreq_update_policy(cpu);
>> + }
>> + mutex_unlock(&amd_pstate_driver_lock);
>> +}
>> +
>> +static int cppc_boost_hold_time_ns = 3 * NSEC_PER_MSEC;
>> +
>> +static inline void amd_pstate_boost_up(struct amd_cpudata *cpudata)
>> +{
>> + u64 hwp_req = READ_ONCE(cpudata->cppc_req_cached);
>> + u64 hwp_cap = READ_ONCE(cpudata->cppc_cap1_cached);
>> + u32 max_limit = (hwp_req & 0xff);
>> + u32 min_limit = (hwp_req & 0xff00) >> 8;
>> + u32 boost_level1;
>> +
>> + /* If max and min are equal or already at max, nothing to boost */
>> + if (max_limit == min_limit)
>> + return;
>> +
>> + /* Set boost max and min to initial value */
>> + if (!cpudata->cppc_boost_min)
>> + cpudata->cppc_boost_min = min_limit;
>> +
>> + boost_level1 = ((AMD_CPPC_NOMINAL_PERF(hwp_cap) + min_limit) >> 1);
>> +
>> + if (cpudata->cppc_boost_min < boost_level1)
>> + cpudata->cppc_boost_min = boost_level1;
>> + else if (cpudata->cppc_boost_min < AMD_CPPC_NOMINAL_PERF(hwp_cap))
>> + cpudata->cppc_boost_min = AMD_CPPC_NOMINAL_PERF(hwp_cap);
>> + else if (cpudata->cppc_boost_min == AMD_CPPC_NOMINAL_PERF(hwp_cap))
>> + cpudata->cppc_boost_min = max_limit;
>> + else
>> + return;
>> +
>> + hwp_req &= ~AMD_CPPC_MIN_PERF(~0L);
>> + hwp_req |= AMD_CPPC_MIN_PERF(cpudata->cppc_boost_min);
>> + wrmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, hwp_req);
>> + cpudata->last_update = cpudata->sample.time;
>> +}
>> +
>> +static inline void amd_pstate_boost_down(struct amd_cpudata *cpudata)
>> +{
>> + bool expired;
>> +
>> + if (cpudata->cppc_boost_min) {
>> + expired = time_after64(cpudata->sample.time, cpudata->last_update +
>> + cppc_boost_hold_time_ns);
>> +
>> + if (expired) {
>> + wrmsrl_safe_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ,
>> + cpudata->cppc_req_cached);
>> + cpudata->cppc_boost_min = 0;
>> + }
>> + }
>> +
>> + cpudata->last_update = cpudata->sample.time;
>> +}
>> +
>> +static inline void amd_pstate_boost_update_util(struct amd_cpudata *cpudata,
>> + u64 time)
>> +{
>> + cpudata->sample.time = time;
>> + if (smp_processor_id() != cpudata->cpu)
>> + return;
>> +
>> + if (cpudata->sched_flags & SCHED_CPUFREQ_IOWAIT) {
>> + bool do_io = false;
>> +
>> + cpudata->sched_flags = 0;
>> + /*
>> + * Set iowait_boost flag and update time. Since IO WAIT flag
>> + * is set all the time, we can't just conclude that there is
>> + * some IO bound activity is scheduled on this CPU with just
>> + * one occurrence. If we receive at least two in two
>> + * consecutive ticks, then we treat as boost candidate.
>> + * This is leveraged from Intel Pstate driver.
>> + */
>> + if (time_before64(time, cpudata->last_io_update + 2 * TICK_NSEC))
>> + do_io = true;
>> +
>> + cpudata->last_io_update = time;
>> +
>> + if (do_io)
>> + amd_pstate_boost_up(cpudata);
>> +
>> + } else {
>> + amd_pstate_boost_down(cpudata);
>> + }
>> +}
>> +
>> +static inline void amd_pstate_cppc_update_hook(struct update_util_data *data,
>> + u64 time, unsigned int flags)
>> +{
>> + struct amd_cpudata *cpudata = container_of(data,
>> + struct amd_cpudata, update_util);
>> +
>> + cpudata->sched_flags |= flags;
>> +
>> + if (smp_processor_id() == cpudata->cpu)
>> + amd_pstate_boost_update_util(cpudata, time);
>> +}
>> +
>> +static void amd_pstate_clear_update_util_hook(unsigned int cpu)
>> +{
>> + struct amd_cpudata *cpudata = all_cpu_data[cpu];
>> +
>> + if (!cpudata->update_util_set)
>> + return;
>> +
>> + cpufreq_remove_update_util_hook(cpu);
>> + cpudata->update_util_set = false;
>> + synchronize_rcu();
>> +}
>> +
>> +static void amd_pstate_set_update_util_hook(unsigned int cpu_num)
>> +{
>> + struct amd_cpudata *cpudata = all_cpu_data[cpu_num];
>> +
>> + if (!cppc_boost) {
>> + if (cpudata->update_util_set)
>> + amd_pstate_clear_update_util_hook(cpudata->cpu);
>> + return;
>> + }
>> +
>> + if (cpudata->update_util_set)
>> + return;
>> +
>> + cpudata->sample.time = 0;
>> + cpufreq_add_update_util_hook(cpu_num, &cpudata->update_util,
>> + amd_pstate_cppc_update_hook);
>> + cpudata->update_util_set = true;
>> +}
>> +
>> +static void amd_pstate_epp_init(unsigned int cpu)
>> +{
>> + struct amd_cpudata *cpudata = all_cpu_data[cpu];
>> + u32 max_perf, min_perf;
>> + u64 value;
>> + s16 epp;
>> + int ret;
>> +
>> + max_perf = READ_ONCE(cpudata->highest_perf);
>> + min_perf = READ_ONCE(cpudata->lowest_perf);
>> +
>> + value = READ_ONCE(cpudata->cppc_req_cached);
>> +
>> + if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
>> + min_perf = max_perf;
>> +
>> + /* Initial min/max values for CPPC Performance Controls Register */
>> + value &= ~AMD_CPPC_MIN_PERF(~0L);
>> + value |= AMD_CPPC_MIN_PERF(min_perf);
>> +
>> + value &= ~AMD_CPPC_MAX_PERF(~0L);
>> + value |= AMD_CPPC_MAX_PERF(max_perf);
>> +
>> + /* CPPC EPP feature require to set zero to the desire perf bit */
>> + value &= ~AMD_CPPC_DES_PERF(~0L);
>> + value |= AMD_CPPC_DES_PERF(0);
>> +
>> + if (cpudata->epp_policy == cpudata->policy)
>> + goto skip_epp;
>> +
>> + cpudata->epp_policy = cpudata->policy;
>> +
>> + if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
>> + epp = amd_pstate_get_epp(cpudata, value);
>> + cpudata->epp_powersave = epp;
>> + if (epp < 0)
>> + goto skip_epp;
>> + /* force the epp value to be zero for performance policy */
>> + epp = 0;
>> + } else {
>> + if (cpudata->epp_powersave < 0)
>> + goto skip_epp;
>> + /* Get BIOS pre-defined epp value */
>> + epp = amd_pstate_get_epp(cpudata, value);
>> + if (epp)
>> + goto skip_epp;
>> + epp = cpudata->epp_powersave;
>> + }
>> + /* Set initial EPP value */
>> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
>> + value &= ~GENMASK_ULL(31, 24);
>> + value |= (u64)epp << 24;
>> + }
>> +
>> +skip_epp:
>> + WRITE_ONCE(cpudata->cppc_req_cached, value);
>> + ret = wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, value);
>> + if (!ret)
>> + cpudata->epp_cached = epp;
>> +}
>> +
>> +static void amd_pstate_set_max_limits(struct amd_cpudata *cpudata)
>> +{
>> + u64 hwp_cap = READ_ONCE(cpudata->cppc_cap1_cached);
>> + u64 hwp_req = READ_ONCE(cpudata->cppc_req_cached);
>> + u32 max_limit = (hwp_cap >> 24) & 0xff;
>> +
>> + hwp_req &= ~AMD_CPPC_MIN_PERF(~0L);
>> + hwp_req |= AMD_CPPC_MIN_PERF(max_limit);
>> + wrmsrl_on_cpu(cpudata->cpu, MSR_AMD_CPPC_REQ, hwp_req);
>> +}
>> +
>> +static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
>> +{
>> + struct amd_cpudata *cpudata;
>> +
>> + if (!policy->cpuinfo.max_freq)
>> + return -ENODEV;
>> +
>> + pr_debug("set_policy: cpuinfo.max %u policy->max %u\n",
>> + policy->cpuinfo.max_freq, policy->max);
>> +
>> + cpudata = all_cpu_data[policy->cpu];
>> + cpudata->policy = policy->policy;
>> +
>> + if (boot_cpu_has(X86_FEATURE_CPPC)) {
>> + mutex_lock(&amd_pstate_limits_lock);
>> +
>> + if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
>> + amd_pstate_clear_update_util_hook(policy->cpu);
>> + amd_pstate_set_max_limits(cpudata);
>> + } else {
>> + amd_pstate_set_update_util_hook(policy->cpu);
>> + }
>> +
>> + if (boot_cpu_has(X86_FEATURE_CPPC))
>> + amd_pstate_epp_init(policy->cpu);
>> +
>> + mutex_unlock(&amd_pstate_limits_lock);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static void amd_pstate_verify_cpu_policy(struct amd_cpudata *cpudata,
>> + struct cpufreq_policy_data *policy)
>> +{
>> + update_boost_state();
>> + cpufreq_verify_within_cpu_limits(policy);
>> +}
>> +
>> +static int amd_pstate_epp_verify_policy(struct cpufreq_policy_data *policy)
>> +{
>> + amd_pstate_verify_cpu_policy(all_cpu_data[policy->cpu], policy);
>> + pr_debug("policy_max =%d, policy_min=%d\n", policy->max, policy->min);
>> + return 0;
>> +}
>> +
>> static struct cpufreq_driver amd_pstate_driver = {
>> .flags = CPUFREQ_CONST_LOOPS | CPUFREQ_NEED_UPDATE_LIMITS,
>> .verify = amd_pstate_verify,
>> @@ -607,8 +1222,20 @@ static struct cpufreq_driver amd_pstate_driver = {
>> .attr = amd_pstate_attr,
>> };
>> +static struct cpufreq_driver amd_pstate_epp_driver = {
>> + .flags = CPUFREQ_CONST_LOOPS,
>> + .verify = amd_pstate_epp_verify_policy,
>> + .setpolicy = amd_pstate_epp_set_policy,
>> + .init = amd_pstate_epp_cpu_init,
>> + .exit = amd_pstate_epp_cpu_exit,
>> + .update_limits = amd_pstate_epp_update_limits,
>> + .name = "amd_pstate_epp",
>> + .attr = amd_pstate_epp_attr,
>> +};
>> +
>> static int __init amd_pstate_init(void)
>> {
>> + static struct amd_cpudata **cpudata;
>> int ret;
>> if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
>> @@ -623,10 +1250,18 @@ static int __init amd_pstate_init(void)
>> if (cpufreq_get_current_driver())
>> return -EEXIST;
>> + if (!epp_off) {
>> + WRITE_ONCE(cppc_active, 1);
>> + if (!default_pstate_driver)
>> + default_pstate_driver = &amd_pstate_epp_driver;
>> + }
>> + pr_info("AMD CPPC loading with %s driver instance.\n", default_pstate_driver->name);
>
> This is pretty noisy, do we really need it on every boot if we can easily check it from sysfs?
>
>> +
>> /* capability check */
>> if (boot_cpu_has(X86_FEATURE_CPPC)) {
>> + if (!cppc_active)
>> + default_pstate_driver->adjust_perf = amd_pstate_adjust_perf;
>> pr_debug("AMD CPPC MSR based functionality is supported\n");
>> - amd_pstate_driver.adjust_perf = amd_pstate_adjust_perf;
>> } else if (shared_mem) {
>> static_call_update(amd_pstate_enable, cppc_enable);
>> static_call_update(amd_pstate_init_perf, cppc_init_perf);
>> @@ -636,6 +1271,10 @@ static int __init amd_pstate_init(void)
>> return -ENODEV;
>> }
>> + cpudata = vzalloc(array_size(sizeof(void *), num_possible_cpus()));
>> + if (!cpudata)
>> + return -ENOMEM;
>> + WRITE_ONCE(all_cpu_data, cpudata);
>> /* enable amd pstate feature */
>> ret = amd_pstate_enable(true);
>> if (ret) {
>> @@ -643,9 +1282,9 @@ static int __init amd_pstate_init(void)
>> return ret;
>> }
>> - ret = cpufreq_register_driver(&amd_pstate_driver);
>> + ret = cpufreq_register_driver(default_pstate_driver);
>> if (ret)
>> - pr_err("failed to register amd_pstate_driver with return %d\n",
>> + pr_err("failed to register amd pstate driver with return %d\n",
>> ret);
>> return ret;
>> @@ -657,6 +1296,15 @@ static int __init amd_pstate_param(char *str)
>> if (!str)
>> return -EINVAL;
>> + if (!strcmp(str, "disable"))
>> + disable_pstate_load = 1;
>> + else if (!strcmp(str, "active")) {
>> + default_pstate_driver = &amd_pstate_epp_driver;
>> + } else if (!strcmp(str, "passive")) {
>> + epp_off = 1;
>> + default_pstate_driver = &amd_pstate_driver;
>> + }
>> +
>> /* enable shared memory type CPPC ,if you processor has no MSR, you have to add this
>> * to your grub to make cppc driver loaded successfully.
>> */
>> diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
>> index 1c4b8659f171..7e6e8cab97b3 100644
>> --- a/include/linux/amd-pstate.h
>> +++ b/include/linux/amd-pstate.h
>> @@ -25,6 +25,7 @@ struct amd_aperf_mperf {
>> u64 aperf;
>> u64 mperf;
>> u64 tsc;
>> + u64 time;
>> };
>> /**
>> @@ -47,6 +48,18 @@ struct amd_aperf_mperf {
>> * @prev: Last Aperf/Mperf/tsc count value read from register
>> * @freq: current cpu frequency value
>> * @boost_supported: check whether the Processor or SBIOS supports boost mode
>> + * @epp_powersave: Last saved CPPC energy performance preference
>> + when policy switched to performance
>> + * @epp_policy: Last saved policy used to set energy-performance preference
>> + * @epp_cached: Cached CPPC energy-performance preference value
>> + * @policy: Cpufreq policy value
>> + * @sched_flags: Store scheduler flags for possible cross CPU update
>> + * @update_util_set: CPUFreq utility callback is set
>> + * @last_update: Time stamp of the last performance state update
>> + * @cppc_boost_min: Last CPPC boosted min performance state
>> + * @cppc_cap1_cached: Cached value of the last CPPC Capabilities MSR
>> + * @update_util: Cpufreq utility callback information
>> + * @sample: the stored performance sample
>> *
>> * The amd_cpudata is key private data for each CPU thread in AMD P-State, and
>> * represents all the attributes and goals that AMD P-State requests at runtime.
>> @@ -72,6 +85,74 @@ struct amd_cpudata {
>> u64 freq;
>> bool boost_supported;
>> +
>> + /* EPP feature related attributes*/
>> + s16 epp_powersave;
>> + s16 epp_policy;
>> + s16 epp_cached;
>> + u32 policy;
>> + u32 sched_flags;
>> + bool update_util_set;
>> + u64 last_update;
>> + u64 last_io_update;
>> + u32 cppc_boost_min;
>> + u64 cppc_cap1_cached;
>> + struct update_util_data update_util;
>> + struct amd_aperf_mperf sample;
>> +};
>> +
>> +/**
>> + * struct amd_pstate_params - global parameters for the performance control
>> + * @ cppc_boost_disabled wheher the core performance boost disabled
>> + */
>> +struct amd_pstate_params {
>> + bool cppc_boost_disabled;
>> +};
>> +
>> +#define AMD_CPPC_EPP_PERFORMANCE 0x00
>> +#define AMD_CPPC_EPP_BALANCE_PERFORMANCE 0x80
>> +#define AMD_CPPC_EPP_BALANCE_POWERSAVE 0xBF
>> +#define AMD_CPPC_EPP_POWERSAVE 0xFF
>> +
>> +/*
>> + * AMD Energy Preference Performance (EPP)
>> + * The EPP is used in the CCLK DPM controller to drive
>> + * the frequency that a core is going to operate during
>> + * short periods of activity. EPP values will be utilized for
>> + * different OS profiles (balanced, performance, power savings)
>> + * display strings corresponding to EPP index in the
>> + * energy_perf_strings[]
>> + * index String
>> + *-------------------------------------
>> + * 0 default
>> + * 1 performance
>> + * 2 balance_performance
>> + * 3 balance_power
>> + * 4 power
>> + */
>> +enum energy_perf_value_index {
>> + EPP_INDEX_DEFAULT = 0,
>> + EPP_INDEX_PERFORMANCE,
>> + EPP_INDEX_BALANCE_PERFORMANCE,
>> + EPP_INDEX_BALANCE_POWERSAVE,
>> + EPP_INDEX_POWERSAVE,
>> +};
>> +
>> +static const char * const energy_perf_strings[] = {
>> + [EPP_INDEX_DEFAULT] = "default",
>> + [EPP_INDEX_PERFORMANCE] = "performance",
>> + [EPP_INDEX_BALANCE_PERFORMANCE] = "balance_performance",
>> + [EPP_INDEX_BALANCE_POWERSAVE] = "balance_power",
>> + [EPP_INDEX_POWERSAVE] = "power",
>> + NULL
>> +};
>> +
>> +static unsigned int epp_values[] = {
>> + [EPP_INDEX_DEFAULT] = 0,
>> + [EPP_INDEX_PERFORMANCE] = AMD_CPPC_EPP_PERFORMANCE,
>> + [EPP_INDEX_BALANCE_PERFORMANCE] = AMD_CPPC_EPP_BALANCE_PERFORMANCE,
>> + [EPP_INDEX_BALANCE_POWERSAVE] = AMD_CPPC_EPP_BALANCE_POWERSAVE,
>> + [EPP_INDEX_POWERSAVE] = AMD_CPPC_EPP_POWERSAVE,
>> };
>> #endif /* _LINUX_AMD_PSTATE_H */
>
[AMD Official Use Only - General]
Hi Mario
> -----Original Message-----
> From: Limonciello, Mario <[email protected]>
> Sent: Tuesday, November 8, 2022 2:34 AM
> To: Yuan, Perry <[email protected]>; [email protected]; Huang,
> Ray <[email protected]>; [email protected]
> Cc: Sharma, Deepak <[email protected]>; Fontenot, Nathan
> <[email protected]>; Deucher, Alexander
> <[email protected]>; Huang, Shimmer
> <[email protected]>; Du, Xiaojian <[email protected]>; Meng,
> Li (Jassmine) <[email protected]>; [email protected]; linux-
> [email protected]
> Subject: Re: [PATCH v3 2/8] Documentation: amd-pstate: add EPP profiles
> introduction
>
> On 11/7/2022 11:56, Perry Yuan wrote:
> > The patch add AMD pstate EPP feature introduction and what EPP
> > preference supported for AMD processors.
> >
> > User can get supported list from
> > energy_performance_available_preferences attribute file, or update
> > current profile to energy_performance_preference file
> >
> > 1) See all EPP profiles
> > $ sudo cat
> >
> /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_available_pref
> > erences default performance balance_performance balance_power power
> >
> > 2) Check current EPP profile
> > $ sudo cat
> > /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference
> > performance
> >
> > 3) Set new EPP profile
> > $ sudo bash -c "echo power >
> /sys/devices/system/cpu/cpu0/cpufreq/energy_performance_preference"
> >
> > Signed-off-by: Perry Yuan <[email protected]>
> > ---
> > Documentation/admin-guide/pm/amd-pstate.rst | 19
> +++++++++++++++++++
> > 1 file changed, 19 insertions(+)
> >
> > diff --git a/Documentation/admin-guide/pm/amd-pstate.rst
> > b/Documentation/admin-guide/pm/amd-pstate.rst
> > index 8f3d30c5a0d8..78c6525d5a49 100644
> > --- a/Documentation/admin-guide/pm/amd-pstate.rst
> > +++ b/Documentation/admin-guide/pm/amd-pstate.rst
> > @@ -262,6 +262,25 @@ lowest non-linear performance in `AMD CPPC
> Performance Capability
> > <perf_cap_>`_.)
> > This attribute is read-only.
> > > +``energy_performance_available_preferences``
> > +
> > +All the supported EPP preference could be selected, List of the
> > +strings that can be set to the ``energy_performance_preference``
> > +attribute those different profiles represent different energy vs
> > +efficiency hints provided to low-level firmware however, the
> > +``default`` represents the epp value is set by platform firmware This
> > +attribute is read-only.
>
> My proposal at rewording it.
>
> A list of all the supported EPP preferences that could be used for
> ``energy_performance_preference` on this system.
> These profiles represent different hints that are provided to the low-level
> firmware about the user's desired energy vs efficiency tradeoff. ``default``
> represents the epp value is set by platform firmware. This attribute is read-
> only.
Make sense.
Fixed in V4 as you suggested.
>
>
> > +
> > +``energy_performance_preference``
> > +
> > +The current energy performance preference can be read from this
> attribute.
> > +and user can change current preference according to energy or
> > +performance needs Please get all support profiles list from
> > +``energy_performance_available_preferences`` attribute, all the
> > +profiles are integer values defined between 0 to 255 when EPP feature
> > +is enabled by platform firmware, if EPP feature is disabled, driver
> > +will ignore the written value This attribute is read-write.
> > +
> > Other performance and frequency values can be read back from
> > ``/sys/devices/system/cpu/cpuX/acpi_cppc/``, see :ref:`cppc_sysfs`.
> >
[AMD Official Use Only - General]
Hi Mario.
> -----Original Message-----
> From: Limonciello, Mario <[email protected]>
> Sent: Tuesday, November 8, 2022 2:10 AM
> To: Yuan, Perry <[email protected]>; [email protected]; Huang,
> Ray <[email protected]>; [email protected]
> Cc: Sharma, Deepak <[email protected]>; Fontenot, Nathan
> <[email protected]>; Deucher, Alexander
> <[email protected]>; Huang, Shimmer
> <[email protected]>; Du, Xiaojian <[email protected]>; Meng,
> Li (Jassmine) <[email protected]>; [email protected]; linux-
> [email protected]
> Subject: Re: [PATCH v3 8/8] cpufreq: amd_pstate: add driver working mode
> status sysfs entry
>
> On 11/7/2022 11:57, Perry Yuan wrote:
> > While amd-pstate driver was loaded with specific driver mode, it will
> > need to check which mode is enabled for the pstate driver,add this
> > sysfs entry to show the current status
> >
> > $ cat /sys/devices/system/cpu/amd-pstate/status
> > active >
> > Signed-off-by: Perry Yuan <[email protected]>
> > ---
> > drivers/cpufreq/amd-pstate.c | 44
> > ++++++++++++++++++++++++++++++++++++
>
> You should update the matching amd-pstate documentation for this new
> sysfs file.
>
> > 1 file changed, 44 insertions(+)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 6958c5fd9e1c..eadcc9d61d39
> 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -65,6 +65,8 @@ static int disable_pstate_load __initdata;
> > static int epp_off __initdata;
> >
> > static struct cpufreq_driver *default_pstate_driver;
> > +static struct cpufreq_driver amd_pstate_epp_driver; static struct
> > +cpufreq_driver amd_pstate_driver;
> > static struct amd_cpudata **all_cpu_data;
> >
> > static struct amd_pstate_params global_params; @@ -819,6 +821,46 @@
> > static ssize_t store_pstate_dynamic_boost(struct kobject *a,
> > return count;
> > }
> >
> > +static ssize_t amd_pstate_show_status(char *buf) {
> > + if (!default_pstate_driver)
> > + return sprintf(buf, "off\n");
> > +
> > + return sprintf(buf, "%s\n", default_pstate_driver ==
> &amd_pstate_epp_driver ?
> > + "active" : "passive");
> > +}
> > +
> > +static int amd_pstate_update_status(const char *buf, size_t size) {
> > + /* FIXME: add driver dynamic switching code */
> > + return 0;
> > +}
>
> So "Effectively" this is read only right now. I think it's better to mark the sysfs
> file as read only and not bother to populate "store"
> callback until you're ready to allow dynamically swapping back and forth.
>
> If you want to keep the code there, then I think you should return an -
> EOPNOTSUPP error code for amd_pstate_update_status.
Yes, changed to return EOPNOTSUPP code in V4.
Please help to take a look.
Thanks .
Perry.
>
> > +
> > +static ssize_t show_status(struct kobject *kobj,
> > + struct kobj_attribute *attr, char *buf) {
> > + ssize_t ret;
> > +
> > + mutex_lock(&amd_pstate_driver_lock);
> > + ret = amd_pstate_show_status(buf);
> > + mutex_unlock(&amd_pstate_driver_lock);
> > +
> > + return ret;
> > +}
> > +
> > +static ssize_t store_status(struct kobject *a, struct kobj_attribute *b,
> > + const char *buf, size_t count) {
> > + char *p = memchr(buf, '\n', count);
> > + int ret;
> > +
> > + mutex_lock(&amd_pstate_driver_lock);
> > + ret = amd_pstate_update_status(buf, p ? p - buf : count);
> > + mutex_unlock(&amd_pstate_driver_lock);
> > +
> > + return ret < 0 ? ret : count;
> > +}
> > +
> > cpufreq_freq_attr_ro(amd_pstate_max_freq);
> > cpufreq_freq_attr_ro(amd_pstate_lowest_nonlinear_freq);
> >
> > @@ -826,6 +868,7 @@ cpufreq_freq_attr_ro(amd_pstate_highest_perf);
> > cpufreq_freq_attr_rw(energy_performance_preference);
> > cpufreq_freq_attr_ro(energy_performance_available_preferences);
> > define_one_global_rw(pstate_dynamic_boost);
> > +define_one_global_rw(status);
> >
> > static struct freq_attr *amd_pstate_attr[] = {
> > &amd_pstate_max_freq,
> > @@ -845,6 +888,7 @@ static struct freq_attr *amd_pstate_epp_attr[] = {
> >
> > static struct attribute *pstate_global_attributes[] = {
> > &pstate_dynamic_boost.attr,
> > + &status.attr,
> > NULL
> > };
> >