linux-kernel - Re: [PATCH v5 1/7] topology: Add a new arch_scale_freq

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Message-ID: <20231107114521.GD954129@bogus>
Date:   Tue, 7 Nov 2023 11:45:21 +0000
From:   Sudeep Holla <sudeep.holla@....com>
To:     Vincent Guittot <vincent.guittot@...aro.org>
Cc:     linux@...linux.org.uk, catalin.marinas@....com, will@...nel.org,
        Sudeep Holla <sudeep.holla@....com>, paul.walmsley@...ive.com,
        palmer@...belt.com, aou@...s.berkeley.edu,
        gregkh@...uxfoundation.org, rafael@...nel.org, mingo@...hat.com,
        peterz@...radead.org, juri.lelli@...hat.com,
        dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
        mgorman@...e.de, bristot@...hat.com, vschneid@...hat.com,
        viresh.kumar@...aro.org, lenb@...nel.org, robert.moore@...el.com,
        lukasz.luba@....com, ionela.voinescu@....com,
        pierre.gondois@....com, beata.michalska@....com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-riscv@...ts.infradead.org, linux-pm@...r.kernel.org,
        linux-acpi@...r.kernel.org, conor.dooley@...rochip.com,
        suagrfillet@...il.com, ajones@...tanamicro.com, lftan@...nel.org
Subject: Re: [PATCH v5 1/7] topology: Add a new arch_scale_freq_reference

On Sat, Nov 04, 2023 at 11:59:01AM +0100, Vincent Guittot wrote:
> Create a new method to get a unique and fixed max frequency. Currently
> cpuinfo.max_freq or the highest (or last) state of performance domain are
> used as the max frequency when computing the frequency for a level of
> utilization but:
> - cpuinfo_max_freq can change at runtime. boost is one example of
>   such change.
> - cpuinfo.max_freq and last item of the PD can be different leading to
>   different results between cpufreq and energy model.
> 
> We need to save the reference frequency that has been used when computing
> the CPUs capacity and use this fixed and coherent value to convert between
> frequency and CPU's capacity.
> 
> In fact, we already save the frequency that has been used when computing
> the capacity of each CPU. We extend the precision to save kHz instead of
> MHz currently and we modify the type to be aligned with other variables
> used when converting frequency to capacity and the other way.
> 

For all the topology related changes here and patch 6/7 and 7/7:

Acked-by: Sudeep Holla <sudeep.holla@....com>

-- 
Regards,
Sudeep