From: Peter Zijlstra <peterz@infradead.org>
To: Stephane Eranian <eranian@google.com>
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu
Subject: Re: [PATCH] perf_event: fix loss of notification with multi-event
Date: Mon, 28 Nov 2011 11:11:00 +0100 [thread overview]
Message-ID: <1322475060.2921.95.camel@twins> (raw)
In-Reply-To: <20111126014731.GA7030@quad>
On Sat, 2011-11-26 at 02:47 +0100, Stephane Eranian wrote:
> Here is a fixed version of Peter's patch.
> I fixed the compilation errors + added the missing
> linked list + spinlock initializations.
>
> I also added the mmap_mutex in perf_poll() to avoid the
> race with perf_set_output(). It's not pretty but it solves
> the problem of a process getting stuck on a sampling buffer
> which is never going to get any samples. This was an unlikely
> scenario but we should take care of it anyway.
>
> This patch solves the issue with loss of buffer notifications
> when sampling on multiple events at the same time. In that
> case fewer than expected samples would be captured.
Hehe, so it actually works eh.. amazing stuff ;-)
OK, I'll stick it in perf/urgent.. Thanks Stephane!
If anybody happens upon a prettier solution, don't be shy and please do
tell us ;-)
next prev parent reply other threads:[~2011-11-28 10:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-26 1:47 [PATCH] perf_event: fix loss of notification with multi-event Stephane Eranian
2011-11-28 10:11 ` Peter Zijlstra [this message]
2011-11-28 10:51 ` Peter Zijlstra
2011-11-28 10:56 ` Peter Zijlstra
2011-12-05 13:16 ` [tip:perf/urgent] perf: Fix " tip-bot for Peter Zijlstra
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