linux-kernel - Re: [PATCH PATCH 2/9] cpufreq: intel_pstate: Use topology_cpu

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Date: Mon, 17 Jun 2024 02:27:02 -0700
From: srinivas pandruvada <srinivas.pandruvada@...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>, 
 "Rafael J. Wysocki" <rafael@...nel.org>, Ricardo Neri
 <ricardo.neri-calderon@...ux.intel.com>,  "Liang, Kan"
 <kan.liang@...ux.intel.com>, Andrew Cooper <andrew.cooper3@...rix.com>
Subject: Re: [PATCH PATCH 2/9] cpufreq: intel_pstate: Use
 topology_cpu_type() to get cpu-type

On Mon, 2024-06-17 at 02:11 -0700, Pawan Gupta wrote:
> Intel pstate driver uses hybrid_get_type() to get the cpu-type of a
> given
> CPU. It uses smp_call_function_single() which is sub-optimal and can
> be
> avoided as cpu-type is also available in the per-cpu topology
> structure.
> 
> Use topology_cpu_type() to get the cpu-type.
> 
> Signed-off-by: Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>

> ---
>  drivers/cpufreq/intel_pstate.c | 14 +++-----------
>  1 file changed, 3 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/cpufreq/intel_pstate.c
> b/drivers/cpufreq/intel_pstate.c
> index 65d3f79104bd..40f5e5b0b45e 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -1951,24 +1951,16 @@ static int knl_get_turbo_pstate(int cpu)
>  	return ret;
>  }
>  
> -static void hybrid_get_type(void *data)
> -{
> -	u8 *cpu_type = data;
> -
> -	*cpu_type = get_this_hybrid_cpu_type();
> -}
> -
>  static int hwp_get_cpu_scaling(int cpu)
>  {
> -	u8 cpu_type = 0;
> +	u8 cpu_type = topology_cpu_type(cpu);
>  
> -	smp_call_function_single(cpu, hybrid_get_type, &cpu_type,
> 1);
>  	/* P-cores have a smaller perf level-to-freqency scaling
> factor. */
> -	if (cpu_type == 0x40)
> +	if (cpu_type == X86_CPU_TYPE_INTEL_CORE)
>  		return hybrid_scaling_factor;
>  
>  	/* Use default core scaling for E-cores */
> -	if (cpu_type == 0x20)
> +	if (cpu_type == X86_CPU_TYPE_INTEL_ATOM)
>  		return core_get_scaling();
>  
>  	/*
>