Hi all,
v3->v4:
- v3 can be found at [3]
- rebased on linux-next 20220310 which contains patches at [4]
requested by Rafael
- 2/3 fixed obsolete comment as reported by Yicong at [5]
- Kept Acked-by,Tested-by as v4 has no code changes compared
to v3, but only a comment fix.
v2->v3:
- v2 can be found at [2]
- Added sanity checking on perf_caps.highest_perf
v1->v2:
- v1 can be found at [1]
- Changed debug prints to the format used on the DT path
- s/init_cpu_capacity_cppc/topology_init_cpu_capacity_cppc
Patches are based on linux next 20220310.
[1] https://lore.kernel.org/lkml/[email protected]/
[2] https://lore.kernel.org/lkml/[email protected]/
[3] https://lore.kernel.org/lkml/[email protected]/
[4] https://lore.kernel.org/linux-acpi/[email protected]/
[5] https://lore.kernel.org/lkml/[email protected]/
Thanks,
Ionela.
Ionela Voinescu (3):
x86, ACPI: rename init_freq_invariance_cppc to
arch_init_invariance_cppc
arch_topology: obtain cpu capacity using information from CPPC
arm64, topology: enable use of init_cpu_capacity_cppc()
arch/arm64/include/asm/topology.h | 4 +++
arch/x86/include/asm/topology.h | 2 +-
drivers/acpi/cppc_acpi.c | 6 ++---
drivers/base/arch_topology.c | 45 ++++++++++++++++++++++++++++---
include/linux/arch_topology.h | 4 +++
5 files changed, 54 insertions(+), 7 deletions(-)
--
2.25.1
Define topology_init_cpu_capacity_cppc() to use highest performance
values from _CPC objects to obtain and set maximum capacity information
for each CPU. acpi_cppc_processor_probe() is a good point at which to
trigger the initialization of CPU (u-arch) capacity values, as at this
point the highest performance values can be obtained from each CPU's
_CPC objects. Architectures can therefore use this functionality
through arch_init_invariance_cppc().
The performance scale used by CPPC is a unified scale for all CPUs in
the system. Therefore, by obtaining the raw highest performance values
from the _CPC objects, and normalizing them on the [0, 1024] capacity
scale, used by the task scheduler, we obtain the CPU capacity of each
CPU.
While an ACPI Notify(0x85) could alert about a change in the highest
performance value, which should in turn retrigger the CPU capacity
computations, this notification is not currently handled by the ACPI
processor driver. When supported, a call to arch_init_invariance_cppc()
would perform the update.
Signed-off-by: Ionela Voinescu <[email protected]>
Acked-by: Sudeep Holla <[email protected]>
Tested-by: Valentin Schneider <[email protected]>
Tested-by: Yicong Yang <[email protected]>
Cc: Sudeep Holla <[email protected]>
---
drivers/base/arch_topology.c | 45 ++++++++++++++++++++++++++++++++---
include/linux/arch_topology.h | 4 ++++
2 files changed, 46 insertions(+), 3 deletions(-)
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index 976154140f0b..1d6636ebaac5 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -339,6 +339,46 @@ bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
return !ret;
}
+#ifdef CONFIG_ACPI_CPPC_LIB
+#include <acpi/cppc_acpi.h>
+
+void topology_init_cpu_capacity_cppc(void)
+{
+ struct cppc_perf_caps perf_caps;
+ int cpu;
+
+ if (likely(acpi_disabled || !acpi_cpc_valid()))
+ return;
+
+ raw_capacity = kcalloc(num_possible_cpus(), sizeof(*raw_capacity),
+ GFP_KERNEL);
+ if (!raw_capacity)
+ return;
+
+ for_each_possible_cpu(cpu) {
+ if (!cppc_get_perf_caps(cpu, &perf_caps) &&
+ (perf_caps.highest_perf >= perf_caps.nominal_perf) &&
+ (perf_caps.highest_perf >= perf_caps.lowest_perf)) {
+ raw_capacity[cpu] = perf_caps.highest_perf;
+ pr_debug("cpu_capacity: CPU%d cpu_capacity=%u (raw).\n",
+ cpu, raw_capacity[cpu]);
+ continue;
+ }
+
+ pr_err("cpu_capacity: CPU%d missing/invalid highest performance.\n", cpu);
+ pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
+ goto exit;
+ }
+
+ topology_normalize_cpu_scale();
+ schedule_work(&update_topology_flags_work);
+ pr_debug("cpu_capacity: cpu_capacity initialization done\n");
+
+exit:
+ free_raw_capacity();
+}
+#endif
+
#ifdef CONFIG_CPU_FREQ
static cpumask_var_t cpus_to_visit;
static void parsing_done_workfn(struct work_struct *work);
@@ -387,9 +427,8 @@ static int __init register_cpufreq_notifier(void)
int ret;
/*
- * on ACPI-based systems we need to use the default cpu capacity
- * until we have the necessary code to parse the cpu capacity, so
- * skip registering cpufreq notifier.
+ * On ACPI-based systems skip registering cpufreq notifier as cpufreq
+ * information is not needed for cpu capacity initialization.
*/
if (!acpi_disabled || !raw_capacity)
return -EINVAL;
diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h
index cce6136b300a..58cbe18d825c 100644
--- a/include/linux/arch_topology.h
+++ b/include/linux/arch_topology.h
@@ -11,6 +11,10 @@
void topology_normalize_cpu_scale(void);
int topology_update_cpu_topology(void);
+#ifdef CONFIG_ACPI_CPPC_LIB
+void topology_init_cpu_capacity_cppc(void);
+#endif
+
struct device_node;
bool topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu);
--
2.25.1
Now that the arch topology driver provides a method of setting CPU
capacity values based on information on highest performance from CPPC,
use this functionality on arm64 platforms.
Signed-off-by: Ionela Voinescu <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Tested-by: Valentin Schneider <[email protected]>
Tested-by: Yicong Yang <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
---
arch/arm64/include/asm/topology.h | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/arm64/include/asm/topology.h b/arch/arm64/include/asm/topology.h
index f386b90a79c8..9fab663dd2de 100644
--- a/arch/arm64/include/asm/topology.h
+++ b/arch/arm64/include/asm/topology.h
@@ -24,6 +24,10 @@ void update_freq_counters_refs(void);
#define arch_scale_freq_capacity topology_get_freq_scale
#define arch_scale_freq_invariant topology_scale_freq_invariant
+#ifdef CONFIG_ACPI_CPPC_LIB
+#define arch_init_invariance_cppc topology_init_cpu_capacity_cppc
+#endif
+
/* Replace task scheduler's default cpu-invariant accounting */
#define arch_scale_cpu_capacity topology_get_cpu_scale
--
2.25.1