linux-kernel - Re: [PATCH V2 3/4] intel_pstate: Ignore scheduler cpufreq callbacks on remote CPUs

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Message-ID: <20170630032741.GT29665@vireshk-i7>
Date:   Fri, 30 Jun 2017 08:57:41 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Cc:     Rafael Wysocki <rjw@...ysocki.net>, Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Len Brown <lenb@...nel.org>, linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        linux-kernel@...r.kernel.org, smuckle.linux@...il.com,
        juri.lelli@....com, Morten.Rasmussen@....com,
        patrick.bellasi@....com, eas-dev@...ts.linaro.org
Subject: Re: [PATCH V2 3/4] intel_pstate: Ignore scheduler cpufreq callbacks
 on remote CPUs

On 29-06-17, 14:23, Srinivas Pandruvada wrote:
> On Thu, 2017-06-29 at 10:56 +0530, Viresh Kumar wrote:
> > From: Steve Muckle <smuckle.linux@...il.com>
> > 
> > In preparation for the scheduler cpufreq callback happening on remote
> > CPUs, check for this case in intel_pstate which currently requires
> > the
> > callback run on the local CPU. Such callbacks are ignored for now.
> Is it possible that we miss a chance to calculate load periodically at
> a predefined interval (10ms default), because the callback happened on
> a different CPU?

We aren't updating cpu->sample.time for remote callbacks here, so no
we shouldn't miss anything.

-- 
viresh