RE: [PATCH v4 09/11] cpufreq: amd-pstate: implement heterogeneous core topology for highest performance initialization

[Yuan, Perry]

[AMD Official Use Only - AMD Internal Distribution Only]

Hi Boris,

> -----Original Message-----
> From: Borislav Petkov <bp@xxxxxxxxx>
> Sent: Wednesday, June 19, 2024 5:24 AM
> To: Yuan, Perry <Perry.Yuan@xxxxxxx>
> Cc: rafael.j.wysocki@xxxxxxxxx; Limonciello, Mario
> <Mario.Limonciello@xxxxxxx>; viresh.kumar@xxxxxxxxxx; Huang, Ray
> <Ray.Huang@xxxxxxx>; Shenoy, Gautham Ranjal
> <gautham.shenoy@xxxxxxx>; Deucher, Alexander
> <Alexander.Deucher@xxxxxxx>; Huang, Shimmer
> <Shimmer.Huang@xxxxxxx>; Du, Xiaojian <Xiaojian.Du@xxxxxxx>; Meng,
> Li (Jassmine) <Li.Meng@xxxxxxx>; linux-pm@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v4 09/11] cpufreq: amd-pstate: implement
> heterogeneous core topology for highest performance initialization
>
> On Mon, Jun 17, 2024 at 02:59:11PM +0800, Perry Yuan wrote:
> > Introduces an optimization to the AMD-Pstate driver by implementing a
> > heterogeneous core topology for the initialization of the highest
> > performance value while driver loading.
> > The two core types supported are "performance" and "efficiency".
> > Each core type has different highest performance and frequency values
> > configured by the platform.  The `amd_pstate` driver needs to identify
> > the type of core to correctly set an appropriate highest perf value.
> >
> > X86_FEATURE_HETERO_CORE_TOPOLOGY is used to identify whether the
> > processor support heterogeneous core type by reading CPUID leaf
> > Fn_0x80000026_EAX and bit 30. if the bit is set as one, then
> > amd_pstate driver will check EBX 30:28 bits to get the core type.
>
> There will be a special ->cpu_type member for that eventually:
>
> https://lore.kernel.org/r/20240617-add-cpu-type-v1-1-
> b88998c01e76@xxxxxxxxxxxxxxx

 Great, I saw your comments in that patchset, hopefully Intel and AMD can have a common design for the core type.
 Feel free to let me know if you want me to try any testing patches.


>
> --
> Regards/Gruss,
>     Boris.
>
> https://people.kernel.org/tglx/notes-about-netiquette