linux-kernel - Re: [PATCH v8 1/4] cpufreq: Introduce an optional cpuinfo_avg

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Message-ID: <20241217042726.isllh5bulpnwql7i@vireshk-i7>
Date: Tue, 17 Dec 2024 09:57:26 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Beata Michalska <beata.michalska@....com>
Cc: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-pm@...r.kernel.org, ionela.voinescu@....com,
	sudeep.holla@....com, will@...nel.org, catalin.marinas@....com,
	rafael@...nel.org, sumitg@...dia.com, yang@...amperecomputing.com,
	vanshikonda@...amperecomputing.com, lihuisong@...wei.com,
	zhanjie9@...ilicon.com, Jonathan Corbet <corbet@....net>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H . Peter Anvin" <hpa@...or.com>, Phil Auld <pauld@...hat.com>,
	x86@...nel.org, linux-doc@...r.kernel.org
Subject: Re: [PATCH v8 1/4] cpufreq: Introduce an optional cpuinfo_avg_freq
 sysfs entry

On 16-12-24, 23:15, Beata Michalska wrote:
> My bad as I must have misinterpreted that message. Although I am not entirely
> sure why this might be unacceptable as it is not such uncommon approach to use
> signed int space to cover both: expected positive value as well as potential
> error code case failure.

This part is fine. The problem is with handling frequency here. Signed int can
capture up to 2 GHz of freq, where as unsigned int can capture up to 4 GHz and
so we would really like to keep it at 4 GHz..

Maybe we need to move to 64 bits for frequency at some point of time, but at
least we should try to not break it for now.

> Enabling the new attribute for all is an option, tough not entirely compelling
> one as exposing a feature that is known not to be supported seems bit
> counterintuitive. On the other hand using cpufreq driver flags won't help much
> as the support for the new attrib is platform-specific, not driver-specific.

-- 
viresh