linux-kernel - Re: [PATCH v4 04/10] perf/x86/intel: Use topology_hw_cpu

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Message-ID: <e7de0a73-23de-4b79-95e2-8a6dd9addfe7@linux.intel.com>
Date: Mon, 21 Oct 2024 09:54:57 -0400
From: "Liang, Kan" <kan.liang@...ux.intel.com>
To: Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
 Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
 Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>,
 x86@...nel.org
Cc: daniel.sneddon@...ux.intel.com, tony.luck@...el.com,
 linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
 linux-perf-users@...r.kernel.org, Josh Poimboeuf <jpoimboe@...nel.org>,
 Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
 "Rafael J. Wysocki" <rafael@...nel.org>,
 Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>,
 Andrew Cooper <andrew.cooper3@...rix.com>,
 Brice Goglin <brice.goglin@...il.com>,
 Mario Limonciello <mario.limonciello@....com>,
 Perry Yuan <Perry.Yuan@....com>, Dapeng Mi <dapeng1.mi@...ux.intel.com>
Subject: Re: [PATCH v4 04/10] perf/x86/intel: Use topology_hw_cpu_type()

Hi Pawan,

On 2024-09-30 10:47 a.m., Pawan Gupta wrote:
> get_this_hybrid_cpu_type() misses a case when cpu-type is populated
> regardless of X86_FEATURE_HYBRID_CPU. This is particularly true for hybrid
> variants that have P or E cores fused off.
> 
> Instead use topology_hw_cpu_type() as it does not rely on hybrid feature to
> enumerate cpu-type. This can also help avoid the model-specific fixup
> get_hybrid_cpu_type().
> 
> Suggested-by: Dave Hansen <dave.hansen@...ux.intel.com>
> Signed-off-by: Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>
> ---
>  arch/x86/events/intel/core.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
> index d879478db3f5..80a2a307e678 100644
> --- a/arch/x86/events/intel/core.c
> +++ b/arch/x86/events/intel/core.c
> @@ -4906,7 +4906,8 @@ static void intel_pmu_check_hybrid_pmus(struct x86_hybrid_pmu *pmu)
>  
>  static struct x86_hybrid_pmu *find_hybrid_pmu_for_cpu(void)
>  {
> -	u8 cpu_type = get_this_hybrid_cpu_type();
> +	struct cpuinfo_x86 *c = &cpu_data(smp_processor_id());
> +	u8 cpu_type = topology_hw_cpu_type(c);
>  	int i;
>  
>  	/*
> 

Dapeng's patch to utilize the native model ID in perf has been merged.
Please replace the get_this_hybrid_cpu_native_id() as well when you spin
a new version.
https://lore.kernel.org/all/20240820073853.1974746-4-dapeng1.mi@linux.intel.com/

Thanks,
Kan