linux-kernel - Re: [PATCH v2 1/3] x86, sched: check for counters overflow in frequency invariant accounting

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Message-ID: <20201022084618.GU2628@hirez.programming.kicks-ass.net>
Date:   Thu, 22 Oct 2020 10:46:18 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Giovanni Gherdovich <ggherdovich@...e.cz>
Cc:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...e.de>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>, x86@...nel.org,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
Subject: Re: [PATCH v2 1/3] x86, sched: check for counters overflow in
 frequency invariant accounting

On Sun, May 31, 2020 at 08:24:51PM +0200, Giovanni Gherdovich wrote:

Hi Giovanni!

> +error:
> +	pr_warn("Scheduler frequency invariance went wobbly, disabling!\n");
> +	schedule_work(&disable_freq_invariance_work);
> +}

I'm getting reports that we trigger this on resume. Would it make sense
to hook into tsc_{save,restore}_sched_clock_state() (or somewhere near
there) to reset the state (basically call init_counter_refs() again to
ensure we're not having to deal with crazy ?