From: Corey Ashford <cjashfor@linux.vnet.ibm.com>
To: Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Frederic Weisbecker <fweisbec@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
Stephane Eranian <eranian@google.com>
Subject: [BUG(?)] perf_events: combining multiple tracepoint events into a group produces no counts on member events
Date: Tue, 30 Nov 2010 17:00:16 -0800 [thread overview]
Message-ID: <4CF59E20.1040301@linux.vnet.ibm.com> (raw)
Hi,
I'm not sure that what I'm seeing is a bug, or was something intentional.
If I place multiple tracepoint events into a group and measure counts of
these events on a process, I get no counts for the tracepoint events
other than the group leader.
Is this expected behavior?
It's not clear to me why this should be the case; grouping shouldn't
have any ill effects on tracepoint events, from my understanding.
I noticed this because my private version of the perf tool has the event
group patch https://lkml.org/lkml/2010/11/24/584 as well as the patch
which fixes the parsing of multiple tracepoint events in the same -e
switch: https://lkml.org/lkml/2010/11/30/460
When I dig into the code a bit, I find that each event opens
successfully, so that's not the problem. If I disable the grouping,
then I get counts for all of the tracepoint events.
- Corey
next reply other threads:[~2010-12-01 1:00 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-01 1:00 Corey Ashford [this message]
2010-12-01 11:46 ` [BUG(?)] perf_events: combining multiple tracepoint events into a group produces no counts on member events Peter Zijlstra
2010-12-01 12:04 ` Peter Zijlstra
2010-12-01 18:02 ` Frederic Weisbecker
2010-12-01 18:52 ` Peter Zijlstra
2010-12-02 17:56 ` Frederic Weisbecker
2010-12-01 18:29 ` Frederic Weisbecker
2010-12-01 18:37 ` Peter Zijlstra
2010-12-01 19:22 ` Corey Ashford
2010-12-01 19:30 ` Peter Zijlstra
2010-12-02 8:58 ` Corey Ashford
2010-12-09 19:56 ` Peter Zijlstra
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