Re: [PATCH v2] x86/cpu: Enable SD_ASYM_PACKING for PKG domain on systems with AMD preferred cores

[Peter Jung]

This does fix the preferred core behavior now and it works now as it should.
Tested with a 9950X on several games, and the scheduler now picks the 
correct cores, which results into a heavy performance improvement, due 
not migrating through the second ccd.

Thanks!

Tested-by: Peter Jung <ptr1337@xxxxxxxxxxx>


On 03.12.24 21:11, Mario Limonciello wrote:
> For the scheduler to use and prefer AMD preferred core rankings set
> SD_ASYM_PACKING for x86_die_flags().
>
> Signed-off-by: Mario Limonciello<mario.limonciello@xxxxxxx>
> ---
> v2:
>   * Fix c23 compatibility issue reported by LKP
> ---
>   arch/x86/kernel/smpboot.c | 11 +++++++++++
>   1 file changed, 11 insertions(+)
>
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index b5a8f0891135b..6a38cf3feb1a9 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -62,6 +62,8 @@
>   #include <linux/mc146818rtc.h>
>   #include <linux/acpi.h>
>   
> +#include <acpi/cppc_acpi.h>
> +
>   #include <asm/acpi.h>
>   #include <asm/cacheinfo.h>
>   #include <asm/desc.h>
> @@ -501,6 +503,15 @@ static int x86_die_flags(void)
>   	    cpu_feature_enabled(X86_FEATURE_AMD_HETEROGENEOUS_CORES))
>   		return x86_sched_itmt_flags();
>   
> +	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
> +	    boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
> +		bool prefcore = false;
> +
> +		amd_detect_prefcore(&prefcore);
> +		if (prefcore)
> +			return x86_sched_itmt_flags();
> +	}
> +
>   	return 0;
>   }
>   
>
> base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37
> -- 2.43.0