linux-kernel - Re: [PATCH] perf/x86/intel: restrict period on Nehalem

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Message-ID: <20190823080706.GA2369@hirez.programming.kicks-ass.net>
Date:   Fri, 23 Aug 2019 10:07:06 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Josh Hunt <johunt@...mai.com>
Cc:     linux-kernel@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
        acme@...nel.org, alexander.shishkin@...ux.intel.com,
        jolsa@...hat.com, namhyung@...nel.org, bpuranda@...mai.com
Subject: Re: [PATCH] perf/x86/intel: restrict period on Nehalem

On Mon, Aug 19, 2019 at 07:13:31PM -0400, Josh Hunt wrote:
> We see our Nehalem machines reporting 'perfevents: irq loop stuck!' in
> some cases when using perf:
> 
> perfevents: irq loop stuck!

> I found that a period limit of 32 was the lowest I could set it to without
> the problem reoccurring. The idea for the patch and approach to find the
> target value were suggested by Ingo and Thomas.
> 
> Signed-off-by: Josh Hunt <johunt@...mai.com>
> Reported-by: Bhupesh Purandare <bpuranda@...mai.com>
> Suggested-by: Thomas Gleixner <tglx@...utronix.de>
> Suggested-by: Ingo Molnar <mingo@...hat.com>
> Link: https://lore.kernel.org/lkml/20150501070226.GB18957@gmail.com/
> Link: https://lore.kernel.org/lkml/alpine.DEB.2.21.1908122133310.7324@nanos.tec.linutronix.de/

Thanks!