Currently amd_pstate sets CPPC enable bit in MSR_AMD_CPPC_ENABLE only
for the CPU where the module_init happened. But MSR_AMD_CPPC_ENABLE is
per-socket. This causes CPPC enable bit to set for only one socket for
servers with more than one physical packages. To fix this write
MSR_AMD_CPPC_ENABLE per-socket.
Also, handle duplicate calls for cppc_enable, because it's called from
per-policy/per-core callbacks and can result in duplicate MSR writes.
Before the fix:
amd@amd:~$ sudo rdmsr -a 0xc00102b1 | uniq --count
192 0
192 1
After the fix:
amd@amd:~$ sudo rdmsr -a 0xc00102b1 | uniq --count
384 1
Suggested-by: Gautham R. Shenoy <[email protected]>
Signed-off-by: Wyes Karny <[email protected]>
---
v1 -> v2:
- Made CPPC enable read/write per-socket
drivers/cpufreq/amd-pstate.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 5a3d4aa0f45a..45b9e359f638 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -63,6 +63,7 @@ static struct cpufreq_driver *current_pstate_driver;
static struct cpufreq_driver amd_pstate_driver;
static struct cpufreq_driver amd_pstate_epp_driver;
static int cppc_state = AMD_PSTATE_DISABLE;
+static bool cppc_enabled;
/*
* AMD Energy Preference Performance (EPP)
@@ -228,7 +229,28 @@ static int amd_pstate_set_energy_pref_index(struct amd_cpudata *cpudata,
static inline int pstate_enable(bool enable)
{
- return wrmsrl_safe(MSR_AMD_CPPC_ENABLE, enable);
+ int ret, cpu;
+ unsigned long logical_proc_id_mask = 0;
+
+ if (enable == cppc_enabled)
+ return 0;
+
+ for_each_present_cpu(cpu) {
+ unsigned long logical_id = topology_logical_die_id(cpu);
+
+ if (test_bit(logical_id, &logical_proc_id_mask))
+ continue;
+
+ set_bit(logical_id, &logical_proc_id_mask);
+
+ ret = wrmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_ENABLE,
+ enable);
+ if (ret)
+ return ret;
+ }
+
+ cppc_enabled = enable;
+ return 0;
}
static int cppc_enable(bool enable)
@@ -236,6 +258,9 @@ static int cppc_enable(bool enable)
int cpu, ret = 0;
struct cppc_perf_ctrls perf_ctrls;
+ if (enable == cppc_enabled)
+ return 0;
+
for_each_present_cpu(cpu) {
ret = cppc_set_enable(cpu, enable);
if (ret)
@@ -251,6 +276,7 @@ static int cppc_enable(bool enable)
}
}
+ cppc_enabled = enable;
return ret;
}
--
2.34.1
On Tue, May 30, 2023 at 09:13:48PM +0800, Karny, Wyes wrote:
> Currently amd_pstate sets CPPC enable bit in MSR_AMD_CPPC_ENABLE only
> for the CPU where the module_init happened. But MSR_AMD_CPPC_ENABLE is
> per-socket. This causes CPPC enable bit to set for only one socket for
> servers with more than one physical packages. To fix this write
> MSR_AMD_CPPC_ENABLE per-socket.
>
> Also, handle duplicate calls for cppc_enable, because it's called from
> per-policy/per-core callbacks and can result in duplicate MSR writes.
>
> Before the fix:
> amd@amd:~$ sudo rdmsr -a 0xc00102b1 | uniq --count
> 192 0
> 192 1
>
> After the fix:
> amd@amd:~$ sudo rdmsr -a 0xc00102b1 | uniq --count
> 384 1
>
> Suggested-by: Gautham R. Shenoy <[email protected]>
> Signed-off-by: Wyes Karny <[email protected]>
> ---
> v1 -> v2:
> - Made CPPC enable read/write per-socket
>
> drivers/cpufreq/amd-pstate.c | 28 +++++++++++++++++++++++++++-
> 1 file changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 5a3d4aa0f45a..45b9e359f638 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -63,6 +63,7 @@ static struct cpufreq_driver *current_pstate_driver;
> static struct cpufreq_driver amd_pstate_driver;
> static struct cpufreq_driver amd_pstate_epp_driver;
> static int cppc_state = AMD_PSTATE_DISABLE;
> +static bool cppc_enabled;
>
> /*
> * AMD Energy Preference Performance (EPP)
> @@ -228,7 +229,28 @@ static int amd_pstate_set_energy_pref_index(struct amd_cpudata *cpudata,
>
> static inline int pstate_enable(bool enable)
> {
> - return wrmsrl_safe(MSR_AMD_CPPC_ENABLE, enable);
> + int ret, cpu;
> + unsigned long logical_proc_id_mask = 0;
> +
> + if (enable == cppc_enabled)
> + return 0;
> +
> + for_each_present_cpu(cpu) {
> + unsigned long logical_id = topology_logical_die_id(cpu);
> +
> + if (test_bit(logical_id, &logical_proc_id_mask))
> + continue;
> +
> + set_bit(logical_id, &logical_proc_id_mask);
> +
> + ret = wrmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_ENABLE,
> + enable);
Thanks Wyes, that makes a lot more sense to me. The MSR is per package on
design. We should only write once per package.
Patch is
Acked-by: Huang Rui <[email protected]>
> + if (ret)
> + return ret;
> + }
> +
> + cppc_enabled = enable;
> + return 0;
> }
>
> static int cppc_enable(bool enable)
> @@ -236,6 +258,9 @@ static int cppc_enable(bool enable)
> int cpu, ret = 0;
> struct cppc_perf_ctrls perf_ctrls;
>
> + if (enable == cppc_enabled)
> + return 0;
> +
> for_each_present_cpu(cpu) {
> ret = cppc_set_enable(cpu, enable);
> if (ret)
> @@ -251,6 +276,7 @@ static int cppc_enable(bool enable)
> }
> }
>
> + cppc_enabled = enable;
> return ret;
> }
>
> --
> 2.34.1
>
On Fri, Jun 16, 2023 at 9:03 AM Huang Rui <[email protected]> wrote:
>
> On Tue, May 30, 2023 at 09:13:48PM +0800, Karny, Wyes wrote:
> > Currently amd_pstate sets CPPC enable bit in MSR_AMD_CPPC_ENABLE only
> > for the CPU where the module_init happened. But MSR_AMD_CPPC_ENABLE is
> > per-socket. This causes CPPC enable bit to set for only one socket for
> > servers with more than one physical packages. To fix this write
> > MSR_AMD_CPPC_ENABLE per-socket.
> >
> > Also, handle duplicate calls for cppc_enable, because it's called from
> > per-policy/per-core callbacks and can result in duplicate MSR writes.
> >
> > Before the fix:
> > amd@amd:~$ sudo rdmsr -a 0xc00102b1 | uniq --count
> > 192 0
> > 192 1
> >
> > After the fix:
> > amd@amd:~$ sudo rdmsr -a 0xc00102b1 | uniq --count
> > 384 1
> >
> > Suggested-by: Gautham R. Shenoy <[email protected]>
> > Signed-off-by: Wyes Karny <[email protected]>
> > ---
> > v1 -> v2:
> > - Made CPPC enable read/write per-socket
> >
> > drivers/cpufreq/amd-pstate.c | 28 +++++++++++++++++++++++++++-
> > 1 file changed, 27 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> > index 5a3d4aa0f45a..45b9e359f638 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -63,6 +63,7 @@ static struct cpufreq_driver *current_pstate_driver;
> > static struct cpufreq_driver amd_pstate_driver;
> > static struct cpufreq_driver amd_pstate_epp_driver;
> > static int cppc_state = AMD_PSTATE_DISABLE;
> > +static bool cppc_enabled;
> >
> > /*
> > * AMD Energy Preference Performance (EPP)
> > @@ -228,7 +229,28 @@ static int amd_pstate_set_energy_pref_index(struct amd_cpudata *cpudata,
> >
> > static inline int pstate_enable(bool enable)
> > {
> > - return wrmsrl_safe(MSR_AMD_CPPC_ENABLE, enable);
> > + int ret, cpu;
> > + unsigned long logical_proc_id_mask = 0;
> > +
> > + if (enable == cppc_enabled)
> > + return 0;
> > +
> > + for_each_present_cpu(cpu) {
> > + unsigned long logical_id = topology_logical_die_id(cpu);
> > +
> > + if (test_bit(logical_id, &logical_proc_id_mask))
> > + continue;
> > +
> > + set_bit(logical_id, &logical_proc_id_mask);
> > +
> > + ret = wrmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_ENABLE,
> > + enable);
>
> Thanks Wyes, that makes a lot more sense to me. The MSR is per package on
> design. We should only write once per package.
>
> Patch is
>
> Acked-by: Huang Rui <[email protected]>
Applied as 6.5 material, thanks!