From: Peter Zijlstra <peterz@infradead.org>
To: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org, fweisbec@gmail.com,
Dave Wootton <dwootton@us.ibm.com>
Subject: Re: Why is PERF_FORMAT_GROUP incompatible with inherited events?
Date: Sun, 14 Feb 2010 13:38:27 +0100 [thread overview]
Message-ID: <1266151107.5273.629.camel@laptop> (raw)
In-Reply-To: <20100214113314.GG13769@brick.ozlabs.ibm.com>
On Sun, 2010-02-14 at 22:33 +1100, Paul Mackerras wrote:
>
> But we don't go and collect the count delta from children without
> PERF_FORMAT_GROUP, so why would we with it?
Yes we do, see perf_event_read_value().
But now that I look at it we don't seem to do so in
perf_output_read_one()... I guess we should fix that.
There is of course the lock inversion in the .read() code reported by
stephane, but other than that is seems to actually support inherited &&
group just fine.
So I think if we fix that lock inversion and make the PERF_SAMPLE_READ
code look like the .read() code it should all work out.
next prev parent reply other threads:[~2010-02-14 12:38 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-12 3:02 Paul Mackerras
2010-02-14 10:12 ` Peter Zijlstra
2010-02-14 11:33 ` Paul Mackerras
2010-02-14 12:38 ` Peter Zijlstra [this message]
2010-02-15 4:56 ` Paul Mackerras
2010-02-15 9:29 ` Peter Zijlstra
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