linux-kernel - Re: [PATCH v2 2/3] x86, sched: Bail out of frequency invariance if turbo frequency is unknown

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Message-ID: <20200601233418.GA15416@ranerica-svr.sc.intel.com>
Date:   Mon, 1 Jun 2020 16:34:18 -0700
From:   Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
To:     Giovanni Gherdovich <ggherdovich@...e.cz>
Cc:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Borislav Petkov <bp@...e.de>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>, x86@...nel.org,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/3] x86, sched: Bail out of frequency invariance if
 turbo frequency is unknown

On Sun, May 31, 2020 at 08:24:52PM +0200, Giovanni Gherdovich wrote:
> There may be CPUs that support turbo boost but don't declare any turbo
> ratio, i.e. their MSR_TURBO_RATIO_LIMIT is all zeroes. In that condition
> scale-invariant calculations can't be performed.
> 
> Signed-off-by: Giovanni Gherdovich <ggherdovich@...e.cz>
> Suggested-by: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>

FWIW,

Tested-by: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>