CPPC/amd-pstate: Fixes to limit actions to online CPUs

[PATCH v2 0/5] CPPC/amd-pstate: Fixes to limit actions to online CPUs

Posted by Gautham R. Shenoy 1 month, 1 week ago

Hello,

This is the v2 of the patchset to restrict certain actions to only
online CPUs instead of present CPUs.

The v1 of this patchset can be found here:
https://lore.kernel.org/lkml/20251105143851.4251-1-gautham.shenoy@amd.com/

Changes between v1 --> v2:

 * Picked up the Reviewed-by tags from Mario for the first four
   patches
 
 * Picked up the Tested-by tags from Chris for the first two patches
 
 * Added a fifth patch to fix calling of cppc_set_auto_sel() for only
   online CPUs in the amd-pstate driver code (Mario)


Gautham R. Shenoy (5):
  ACPI: CPPC: Detect preferred core availability on online CPUs
  ACPI: CPPC: Check _CPC validity for only the online CPUs
  ACPI: CPPC: Perform fast check switch only for online CPUs
  ACPI: CPPC: Limit perf ctrs in PCC check only to online CPUs
  cpufreq/amd-pstate: Call cppc_set_auto_sel() only for online CPUs

 arch/x86/kernel/acpi/cppc.c  | 2 +-
 drivers/acpi/cppc_acpi.c     | 6 +++---
 drivers/cpufreq/amd-pstate.c | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

-- 
2.34.1

Re: [PATCH v2 0/5] CPPC/amd-pstate: Fixes to limit actions to online CPUs

Posted by Rafael J. Wysocki 1 month, 1 week ago

Hi,

On Fri, Nov 7, 2025 at 8:42 AM Gautham R. Shenoy <gautham.shenoy@amd.com> wrote:
>
> Hello,
>
> This is the v2 of the patchset to restrict certain actions to only
> online CPUs instead of present CPUs.
>
> The v1 of this patchset can be found here:
> https://lore.kernel.org/lkml/20251105143851.4251-1-gautham.shenoy@amd.com/
>
> Changes between v1 --> v2:
>
>  * Picked up the Reviewed-by tags from Mario for the first four
>    patches
>
>  * Picked up the Tested-by tags from Chris for the first two patches
>
>  * Added a fifth patch to fix calling of cppc_set_auto_sel() for only
>    online CPUs in the amd-pstate driver code (Mario)
>
>
> Gautham R. Shenoy (5):
>   ACPI: CPPC: Detect preferred core availability on online CPUs
>   ACPI: CPPC: Check _CPC validity for only the online CPUs
>   ACPI: CPPC: Perform fast check switch only for online CPUs
>   ACPI: CPPC: Limit perf ctrs in PCC check only to online CPUs

The above 4 patches applied as 6.18-rc material.

>   cpufreq/amd-pstate: Call cppc_set_auto_sel() only for online CPUs

And I'm leaving this one to Mario.

Thanks!

Re: [PATCH v2 0/5] CPPC/amd-pstate: Fixes to limit actions to online CPUs

Posted by Chris Harris 1 month, 1 week ago

Hi, I've tested all five v2 patches and have observed no issues in the
use case the bug report was based upon.  I continue to successfully
receive the desired amd-pstate scaling driver when 'nosmt=force' and
'amd_pstate=passive' are set.  I've not tested other cases/scenarios
for which the additional hardening/patches may have been intended.

Thank you again for the rapid efforts that went into this solution.

Chris Harris

On Fri, Nov 7, 2025 at 9:41 AM Rafael J. Wysocki <rafael@kernel.org> wrote:
>
> Hi,
>
> On Fri, Nov 7, 2025 at 8:42 AM Gautham R. Shenoy <gautham.shenoy@amd.com> wrote:
> >
> > Hello,
> >
> > This is the v2 of the patchset to restrict certain actions to only
> > online CPUs instead of present CPUs.
> >
> > The v1 of this patchset can be found here:
> > https://lore.kernel.org/lkml/20251105143851.4251-1-gautham.shenoy@amd.com/
> >
> > Changes between v1 --> v2:
> >
> >  * Picked up the Reviewed-by tags from Mario for the first four
> >    patches
> >
> >  * Picked up the Tested-by tags from Chris for the first two patches
> >
> >  * Added a fifth patch to fix calling of cppc_set_auto_sel() for only
> >    online CPUs in the amd-pstate driver code (Mario)
> >
> >
> > Gautham R. Shenoy (5):
> >   ACPI: CPPC: Detect preferred core availability on online CPUs
> >   ACPI: CPPC: Check _CPC validity for only the online CPUs
> >   ACPI: CPPC: Perform fast check switch only for online CPUs
> >   ACPI: CPPC: Limit perf ctrs in PCC check only to online CPUs
>
> The above 4 patches applied as 6.18-rc material.
>
> >   cpufreq/amd-pstate: Call cppc_set_auto_sel() only for online CPUs
>
> And I'm leaving this one to Mario.
>
> Thanks!