topology/sysfs, cpufreq/intel_pstate: Populate cpu_capacity

[PATCH 0/2] topology/sysfs, cpufreq/intel_pstate: Populate cpu_capacity

Posted by Ricardo Neri 7 months, 4 weeks ago

Hi,

Capacity-aware scheduling is now supported on Intel hybrid processors. It
makes sense now to populate the interface /sys/devices/system/cpu/cpuN/
cpu_capacity. User space entities can use this information to implement
policy such as utilization clamps.

This interface currently lives in arch_topology.c. Rather than implementing
the interface again for x86, we can move it to a common location in
topology.c from which other architectures can also benefit and populate
using their own mechanisms.

I tested this patchset on Intel Alder Lake and DragonBoard 845c. The
interfaces are populated correctly.

I'd appreciate any feedback!

Thanks and BR,
Ricardo
Ricardo Neri (2):
  arch_topology: Relocate cpu_scale to topology.[h|c]
  cpufreq: intel_pstate: Populate the cpu_capacity sysfs entries

 drivers/base/arch_topology.c   | 52 ----------------------------------
 drivers/base/topology.c        | 52 ++++++++++++++++++++++++++++++++++
 drivers/cpufreq/intel_pstate.c |  2 ++
 include/linux/arch_topology.h  |  8 ------
 include/linux/topology.h       |  9 ++++++
 5 files changed, 63 insertions(+), 60 deletions(-)

-- 
2.43.0

Re: [PATCH 0/2] topology/sysfs, cpufreq/intel_pstate: Populate cpu_capacity

Posted by Rafael J. Wysocki 7 months, 1 week ago

On Sat, Apr 19, 2025 at 4:49 AM Ricardo Neri
<ricardo.neri-calderon@linux.intel.com> wrote:
>
> Hi,
>
> Capacity-aware scheduling is now supported on Intel hybrid processors. It
> makes sense now to populate the interface /sys/devices/system/cpu/cpuN/
> cpu_capacity. User space entities can use this information to implement
> policy such as utilization clamps.
>
> This interface currently lives in arch_topology.c. Rather than implementing
> the interface again for x86, we can move it to a common location in
> topology.c from which other architectures can also benefit and populate
> using their own mechanisms.
>
> I tested this patchset on Intel Alder Lake and DragonBoard 845c. The
> interfaces are populated correctly.
>
> I'd appreciate any feedback!
>
> Thanks and BR,
> Ricardo
> Ricardo Neri (2):
>   arch_topology: Relocate cpu_scale to topology.[h|c]
>   cpufreq: intel_pstate: Populate the cpu_capacity sysfs entries
>
>  drivers/base/arch_topology.c   | 52 ----------------------------------
>  drivers/base/topology.c        | 52 ++++++++++++++++++++++++++++++++++
>  drivers/cpufreq/intel_pstate.c |  2 ++
>  include/linux/arch_topology.h  |  8 ------
>  include/linux/topology.h       |  9 ++++++
>  5 files changed, 63 insertions(+), 60 deletions(-)
>
> --

Both patches applied as 6.16 material, thanks!