linux-kernel - Re: [PATCH v4 2/2] cpufreq: CPPC: Change FIE default

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <638e0a6e-10d2-8552-a61f-c4c001a2cbe9@arm.com>
Date:   Mon, 22 Aug 2022 13:08:51 +0100
From:   Lukasz Luba <lukasz.luba@....com>
To:     Jeremy Linton <jeremy.linton@....com>
Cc:     rafael@...nel.org, lenb@...nel.org, viresh.kumar@...aro.org,
        robert.moore@...el.com, punit.agrawal@...edance.com,
        ionela.voinescu@....com, pierre.gondois@....com,
        linux-kernel@...r.kernel.org, devel@...ica.org,
        linux-pm@...r.kernel.org, linux-acpi@...r.kernel.org
Subject: Re: [PATCH v4 2/2] cpufreq: CPPC: Change FIE default



On 8/19/22 17:25, 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@....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.

LGTM

Reviewed-by: Lukasz Luba <lukasz.luba@....com>