linux-kernel - Re: [PATCH v2 7/7] cpufreq: make schedutil the default for arm and arm64

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Date:   Thu, 30 Jul 2020 10:24:08 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Ionela Voinescu <ionela.voinescu@....com>
Cc:     rjw@...ysocki.net, dietmar.eggemann@....com,
        catalin.marinas@....com, sudeep.holla@....com, will@...nel.org,
        linux@...linux.org.uk, mingo@...hat.com, peterz@...radead.org,
        linux-pm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org,
        Valentin Schneider <valentin.schneider@....com>
Subject: Re: [PATCH v2 7/7] cpufreq: make schedutil the default for arm and
 arm64

On 22-07-20, 10:37, Ionela Voinescu wrote:
> From: Valentin Schneider <valentin.schneider@....com>
> 
> schedutil is already a hard-requirement for EAS, which has lead to making
> it default on arm (when CONFIG_BIG_LITTLE), see:
> 
>   commit 8fdcca8e254a ("cpufreq: Select schedutil when using big.LITTLE")
> 
> One thing worth pointing out is that schedutil isn't only relevant for
> asymmetric CPU capacity systems; for instance, schedutil is the only
> governor that honours util-clamp performance requests. Another good example
> of this is x86 switching to using it by default in:
> 
>   commit a00ec3874e7d ("cpufreq: intel_pstate: Select schedutil as the default governor")
> 
> Arguably it should be made the default for all architectures, but it seems
> better to wait for them to also gain frequency invariance powers. Make it
> the default for arm && arm64 for now.
> 
> Signed-off-by: Valentin Schneider <valentin.schneider@....com>
> Signed-off-by: Ionela Voinescu <ionela.voinescu@....com>
> Cc: Catalin Marinas <catalin.marinas@....com>
> Cc: Will Deacon <will@...nel.org>
> Cc: Russell King <linux@...linux.org.uk>
> Cc: Rafael J. Wysocki <rjw@...ysocki.net>
> Cc: Viresh Kumar <viresh.kumar@...aro.org>
> ---
>  drivers/cpufreq/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
> index e91750132552..2c7171e0b001 100644
> --- a/drivers/cpufreq/Kconfig
> +++ b/drivers/cpufreq/Kconfig
> @@ -37,7 +37,7 @@ config CPU_FREQ_STAT
>  choice
>  	prompt "Default CPUFreq governor"
>  	default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1100_CPUFREQ || ARM_SA1110_CPUFREQ
> -	default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if BIG_LITTLE
> +	default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if ARM64 || ARM
>  	default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if X86_INTEL_PSTATE && SMP
>  	default CPU_FREQ_DEFAULT_GOV_PERFORMANCE
>  	help

Applied. Thanks.

-- 
viresh