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

Yuan, Perry
2024-06-19T03:25:39Z

[AMD Official Use Only - AMD Internal Distribution Only]

Hi Boris,

> -----Original Message-----
> From: Borislav Petkov <bp@alien8.de>
> Sent: Wednesday, June 19, 2024 5:24 AM
> To: Yuan, Perry <Perry.Yuan@amd.com>
> Cc: rafael.j.wysocki@intel.com; Limonciello, Mario
> <Mario.Limonciello@amd.com>; viresh.kumar@linaro.org; Huang, Ray
> <Ray.Huang@amd.com>; Shenoy, Gautham Ranjal
> <gautham.shenoy@amd.com>; Deucher, Alexander
> <Alexander.Deucher@amd.com>; Huang, Shimmer
> <Shimmer.Huang@amd.com>; Du, Xiaojian <Xiaojian.Du@amd.com>; Meng,
> Li (Jassmine) <Li.Meng@amd.com>; linux-pm@vger.kernel.org; linux-
> kernel@vger.kernel.org
> 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@linux.intel.com

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