linux-kernel - Re: [PATCH] cpufreq: intel_pstate: Update Balance performance EPP for Emerald Rapids

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Message-ID: <c15a8a105308262856ee14bab558d34df8bdf92a.camel@linux.intel.com>
Date: Thu, 01 Aug 2024 12:42:21 -0700
From: srinivas pandruvada <srinivas.pandruvada@...ux.intel.com>
To: Pedro Henrique Kopper <pedro.kopper@...onical.com>, rafael@...nel.org, 
	lenb@...nel.org, viresh.kumar@...aro.org
Cc: linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cpufreq: intel_pstate: Update Balance performance EPP
 for Emerald Rapids

On Thu, 2024-08-01 at 13:41 -0300, Pedro Henrique Kopper wrote:
> On Intel Emerald Rapids machines, we ship the Energy Performance
> Preference
> (EPP) default for balance_performance as 128. However, during an
> internal
> investigation together with Intel, we have determined that 32 is a
> more
> suitable value. This leads to significant improvements in both
> performance
> and energy:
> 
> POV-Ray: 32% faster | 12% less energy
> OpenSSL: 12% faster | energy within 1%
> Build Linux Kernel: 29% faster | 18% less energy
> 
> Therefore, we should move the default EPP for balance_performance to
> 32.
> This is in line with what has already been done for Sapphire Rapids.
> 
> Signed-off-by: Pedro Henrique Kopper <pedro.kopper@...onical.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>

> ---
>  drivers/cpufreq/intel_pstate.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/cpufreq/intel_pstate.c
> b/drivers/cpufreq/intel_pstate.c
> index 392a8000b238..c0278d023cfc 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -3405,6 +3405,7 @@ static const struct x86_cpu_id
> intel_epp_default[] = {
>  	 */
>  	X86_MATCH_VFM(INTEL_ALDERLAKE_L,
> HWP_SET_DEF_BALANCE_PERF_EPP(102)),
>  	X86_MATCH_VFM(INTEL_SAPPHIRERAPIDS_X,
> HWP_SET_DEF_BALANCE_PERF_EPP(32)),
> +	X86_MATCH_VFM(INTEL_EMERALDRAPIDS_X,
> HWP_SET_DEF_BALANCE_PERF_EPP(32)),
>  	X86_MATCH_VFM(INTEL_METEORLAKE_L,
> HWP_SET_EPP_VALUES(HWP_EPP_POWERSAVE,
>  		      179, 64, 16)),
>  	X86_MATCH_VFM(INTEL_ARROWLAKE,
> HWP_SET_EPP_VALUES(HWP_EPP_POWERSAVE,