linux-kernel - Re: [RESEND PATCH 2/2] perf/x86: improve the event scheduling to avoid unnecessary pmu

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Message-ID: <Yi8fELo+k9gmkJIa@hirez.programming.kicks-ass.net>
Date:   Mon, 14 Mar 2022 11:55:12 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Wen Yang <wenyang@...ux.alibaba.com>
Cc:     Stephane Eranian <eranian@...gle.com>,
        Wen Yang <simon.wy@...baba-inc.com>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        mark rutland <mark.rutland@....com>,
        jiri olsa <jolsa@...hat.com>,
        namhyung kim <namhyung@...nel.org>,
        borislav petkov <bp@...en8.de>, x86@...nel.org,
        "h. peter anvin" <hpa@...or.com>, linux-perf-users@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [RESEND PATCH 2/2] perf/x86: improve the event scheduling to
 avoid unnecessary pmu_stop/start

On Thu, Mar 10, 2022 at 11:50:33AM +0800, Wen Yang wrote:

> As you pointed out, some non-compliant rdpmc can cause problems. But you
> also know that linux is the foundation of cloud servers, and many
> third-party programs run on it (we don't have any code for it), and we can
> only observe that the monitoring data will jitter abnormally (the
> probability of this issue is not high, about dozens of tens of thousands of
> machines).

This might be a novel insight, but I *really* don't give a crap about
any of that. If they're not using it right, they get to keep the pieces.

I'd almost make it reschedule more to force them to fix their stuff.