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SubjectRe: [PATCH 3/8] cpupower: Add CPUPOWER_CAP_AMD_HW_PSTATE cpuid caps flag
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On 1/22/21 10:38 AM, Nathan Fontenot wrote:
> Add a check in get_cpu_info() for the ability to read frequencies
> from hardware and set the CPUPOWER_CAP_AMD_HW_PSTATE cpuid flag.
> The cpuid flag is set when CPUID_80000007_EDX[7] is set,
> which is all families >= 10h. The check excludes family 14h
> because HW pstate reporting was not implemented on family 14h.
>
> This is intended to reduce family checks in the main code paths.
>
> Signed-off-by: Nathan Fontenot <nathan.fontenot@amd.com>
> ---
> tools/power/cpupower/utils/helpers/amd.c | 6 +-----
> tools/power/cpupower/utils/helpers/cpuid.c | 12 +++++++++---
> tools/power/cpupower/utils/helpers/helpers.h | 1 +
> 3 files changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/tools/power/cpupower/utils/helpers/amd.c b/tools/power/cpupower/utils/helpers/amd.c
> index 34368436bbd6..496844a20fe2 100644
> --- a/tools/power/cpupower/utils/helpers/amd.c
> +++ b/tools/power/cpupower/utils/helpers/amd.c
> @@ -94,11 +94,7 @@ int decode_pstates(unsigned int cpu, unsigned int cpu_family,
> union core_pstate pstate;
> unsigned long long val;
>
> - /* Only read out frequencies from HW when CPU might be boostable
> - to keep the code as short and clean as possible.
> - Otherwise frequencies are exported via ACPI tables.
> - */

Please update comment instead of deleting it.

> - if (cpu_family < 0x10 || cpu_family == 0x14)
> + if (!(cpupower_cpu_info.caps & CPUPOWER_CAP_AMD_HW_PSTATE))
> return -1;
>
> if (read_msr(cpu, MSR_AMD_PSTATE_LIMIT, &val))
> diff --git a/tools/power/cpupower/utils/helpers/cpuid.c b/tools/power/cpupower/utils/helpers/cpuid.c
> index f9a66a430b72..d577220a193b 100644
> --- a/tools/power/cpupower/utils/helpers/cpuid.c
> +++ b/tools/power/cpupower/utils/helpers/cpuid.c
> @@ -128,9 +128,15 @@ int get_cpu_info(struct cpupower_cpu_info *cpu_info)
> /* AMD or Hygon Boost state enable/disable register */
> if (cpu_info->vendor == X86_VENDOR_AMD ||
> cpu_info->vendor == X86_VENDOR_HYGON) {
> - if (ext_cpuid_level >= 0x80000007 &&
> - (cpuid_edx(0x80000007) & (1 << 9)))
> - cpu_info->caps |= CPUPOWER_CAP_AMD_CPB;
> + if (ext_cpuid_level >= 0x80000007) {
> + if (cpuid_edx(0x80000007) & (1 << 9))
> + cpu_info->caps |= CPUPOWER_CAP_AMD_CPB;
> +
> + if ((cpuid_edx(0x80000007) & (1 << 7)) &&
> + cpu_info->family != 0x14)
> + /* HW pstate was not implemented in family 0x14 */
> + cpu_info->caps |= CPUPOWER_CAP_AMD_HW_PSTATE;
> + }
>
> if (ext_cpuid_level >= 0x80000008 &&
> cpuid_ebx(0x80000008) & (1 << 4))
> diff --git a/tools/power/cpupower/utils/helpers/helpers.h b/tools/power/cpupower/utils/helpers/helpers.h
> index a84f85a9dbd2..5f61eefff5b2 100644
> --- a/tools/power/cpupower/utils/helpers/helpers.h
> +++ b/tools/power/cpupower/utils/helpers/helpers.h
> @@ -70,6 +70,7 @@ enum cpupower_cpu_vendor {X86_VENDOR_UNKNOWN = 0, X86_VENDOR_INTEL,
> #define CPUPOWER_CAP_IS_SNB 0x00000020
> #define CPUPOWER_CAP_INTEL_IDA 0x00000040
> #define CPUPOWER_CAP_AMD_RDPRU 0x00000080
> +#define CPUPOWER_CAP_AMD_HW_PSTATE 0x00000100
>
> #define CPUPOWER_AMD_CPBDIS 0x02000000
>
>
>

thanks,
-- Shuah

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