Re: [PATCH v3 2/2] cpufreq: CPPC: Change FIE default

From: Viresh Kumar <viresh.kumar@linaro.org>
To: Jeremy Linton <jeremy.linton@arm.com>
Cc: linux-acpi@vger.kernel.org, rafael@kernel.or, lenb@kernel.org,
	robert.moore@intel.com, punit.agrawal@bytedance.com,
	lukasz.luba@arm.com, ionela.voinescu@arm.com,
	pierre.gondois@arm.com, linux-kernel@vger.kernel.org,
	devel@acpica.org, linux-pm@vger.kernel.org
Subject: Re: [PATCH v3 2/2] cpufreq: CPPC: Change FIE default
Date: Wed, 24 Aug 2022 11:44:30 +0530	[thread overview]
Message-ID: <20220824061430.3aflygc4gno5j47y@vireshk-i7> (raw)
In-Reply-To: <20220818211619.4193362-3-jeremy.linton@arm.com>

On 18-08-22, 16:16, Jeremy Linton wrote:
> FIE is mostly implemented as PCC mailboxes on arm machines.  This was
> enabled by default without any data suggesting that it does anything
> but hurt system performance. Lets change the default to 'n' until
> hardware appears which clearly benefits.
> 
> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
> ---
>  drivers/cpufreq/Kconfig.arm | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> index 954749afb5fe..ad66d8f15db0 100644
> --- a/drivers/cpufreq/Kconfig.arm
> +++ b/drivers/cpufreq/Kconfig.arm
> @@ -22,7 +22,7 @@ config ACPI_CPPC_CPUFREQ
>  config ACPI_CPPC_CPUFREQ_FIE
>  	bool "Frequency Invariance support for CPPC cpufreq driver"
>  	depends on ACPI_CPPC_CPUFREQ && GENERIC_ARCH_TOPOLOGY
> -	default y
> +	default n
>  	help
>  	  This extends frequency invariance support in the CPPC cpufreq driver,
>  	  by using CPPC delivered and reference performance counters.

Why is this required after we have the first patch in ?

-- 
viresh