On Tue, Oct 15, 2024 at 04:36:34PM -0500, Mario Limonciello wrote:
> From: Perry Yuan <perry.yuan@xxxxxxx>
>
> Add new feature bit that indicates support for workload based
> heuristic feedback to OS for scheduling decisions.
> When the bit set, threads are classified during runtime into
> enumerated classes. The classes represent thread performance/power
> characteristics that may benefit from special scheduling behaviors.
>
> Signed-off-by: Perry Yuan <perry.yuan@xxxxxxx>
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@xxxxxxx>
> ---
> arch/x86/include/asm/cpufeatures.h | 1 +
> arch/x86/kernel/cpu/scattered.c | 1 +
> 2 files changed, 2 insertions(+)
>
> diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
> index cea1ed82aeb4..3e8e67b8ec7a 100644
> --- a/arch/x86/include/asm/cpufeatures.h
> +++ b/arch/x86/include/asm/cpufeatures.h
> @@ -474,6 +474,7 @@
> #define X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT (21*32+ 4) /* Clear branch history at vmexit using SW loop */
> #define X86_FEATURE_FAST_CPPC (21*32 + 5) /* AMD Fast CPPC */
> #define X86_FEATURE_HETERO_CORE_TOPOLOGY (21*32 + 6) /* Heterogeneous Core Topology */
> +#define X86_FEATURE_WORKLOAD_CLASS (21*32 + 7) /* Workload Classification */
>
> /*
> * BUG word(s)
> diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
> index 3bba55323163..b6547bab9e23 100644
> --- a/arch/x86/kernel/cpu/scattered.c
> +++ b/arch/x86/kernel/cpu/scattered.c
> @@ -49,6 +49,7 @@ static const struct cpuid_bit cpuid_bits[] = {
> { X86_FEATURE_MBA, CPUID_EBX, 6, 0x80000008, 0 },
> { X86_FEATURE_SMBA, CPUID_EBX, 2, 0x80000020, 0 },
> { X86_FEATURE_BMEC, CPUID_EBX, 3, 0x80000020, 0 },
> + { X86_FEATURE_WORKLOAD_CLASS, CPUID_EAX, 22, 0x80000021, 0 },
> { X86_FEATURE_PERFMON_V2, CPUID_EAX, 0, 0x80000022, 0 },
> { X86_FEATURE_AMD_LBR_V2, CPUID_EAX, 1, 0x80000022, 0 },
> { X86_FEATURE_AMD_LBR_PMC_FREEZE, CPUID_EAX, 2, 0x80000022, 0 },
> --
> 2.43.0
>
