From: Peter Zijlstra <peterz@infradead.org>
To: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Paul Mackerras <paulus@samba.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Carl Love <carll@us.ibm.com>, Maynard Johnson <mpjohn@us.ibm.com>,
stephane eranian <eranian@googlemail.com>
Subject: Re: [BUG] perf_events: PERF_FORMAT_GROUP not working correctly when monitoring another task
Date: Thu, 06 May 2010 22:22:40 +0200 [thread overview]
Message-ID: <1273177360.1642.280.camel@laptop> (raw)
In-Reply-To: <4BE321F8.1050309@linux.vnet.ibm.com>
On Thu, 2010-05-06 at 13:09 -0700, Corey Ashford wrote:
> The patch works with the test case I provided, but for some reason it
> breaks the normal operation of the libpfm4 "task" utility. If I put
> more than one event in a group, I get zero counts on all but the first
> event. That's even if I don't use the PERF_FORMAT_GROUP option.
Bugger,.. weird though, I can't see how it would affect the state before
the counters get detached from their context (exit() / close()).
> So something appears to be messed up. I will see if I can construct an
> arch-independent test case which demonstrates the problem.
That would be awesome, thanks!
next prev parent reply other threads:[~2010-05-06 20:22 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-04 2:06 [BUG] perf_events: PERF_FORMAT_GROUP not working correctly when monitoring another task Corey Ashford
2010-05-06 15:42 ` Peter Zijlstra
2010-05-06 20:09 ` Corey Ashford
2010-05-06 20:22 ` Peter Zijlstra [this message]
2010-05-07 2:40 ` Corey Ashford
2010-05-07 18:41 ` [tip:perf/core] perf: Fix exit() vs PERF_FORMAT_GROUP tip-bot for Peter Zijlstra
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