From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Stephane Eranian <eranian@google.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
Ingo Molnar <mingo@elte.hu>,
Markus Trippelsdorf <markus@trippelsdorf.de>,
linux-kernel@vger.kernel.org, Paul Mackerras <paulus@samba.org>
Subject: Re: WARNING: at arch/x86/kernel/cpu/perf_event.c:989
Date: Mon, 06 Feb 2012 15:29:28 +0100 [thread overview]
Message-ID: <1328538568.2482.5.camel@laptop> (raw)
In-Reply-To: <CABPqkBQnDToQczbgW4dCXiu3x2ZTXjAuKS_q_hJ=28Pu_2HexQ@mail.gmail.com>
On Mon, 2012-02-06 at 15:13 +0100, Stephane Eranian wrote:
> Ok, I found the problem!
>
> it comes from perf_adjust_freq_unthr_context() vs perf_adjust_period().
> The latter can under certain condition stop and restart the event. So we
> had:
>
> stop()
> if (delta > 0) {
> perf_adjust_period() {
> if (period > 8*...) {
> stop()
> ...
> start()
> }
> }
> }
> start()
>
> Could have a double stop() and double start(), thus triggering the warning in
> x86_pmu_start().
>
> Will post a patch shortly to fix this.
Nice, thanks for looking at this!
next prev parent reply other threads:[~2012-02-06 14:29 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-02 21:17 Markus Trippelsdorf
2012-02-02 21:32 ` Markus Trippelsdorf
2012-02-02 22:22 ` Stephane Eranian
2012-02-04 13:51 ` Ingo Molnar
2012-02-04 18:09 ` Stephane Eranian
2012-02-06 9:54 ` Stephane Eranian
2012-02-06 10:12 ` Eric Dumazet
2012-02-06 10:40 ` Stephane Eranian
2012-02-06 11:11 ` Eric Dumazet
2012-02-06 14:13 ` Stephane Eranian
2012-02-06 14:29 ` Peter Zijlstra [this message]
2012-02-06 14:32 ` Stephane Eranian
2012-02-06 15:02 ` Peter Zijlstra
2012-02-06 14:38 ` Ingo Molnar
2012-02-06 14:41 ` Stephane Eranian
2012-02-06 15:47 ` Ingo Molnar
2012-02-06 20:44 ` Stephane Eranian
2012-02-06 20:58 ` Peter Zijlstra
2012-02-06 21:25 ` Stephane Eranian
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