linux-kernel - Re: [patch 9/9] pref: session: Break event ordering when timestamps are missing

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Message-ID: <20101209173247.GB15579@ghostprotocols.net>
Date:	Thu, 9 Dec 2010 15:32:47 -0200
From:	Arnaldo Carvalho de Melo <acme@...hat.com>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	Ian Munsie <imunsie@....ibm.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ingo Molnar <mingo@...e.hu>
Subject: Re: [patch 9/9] pref: session: Break event ordering when
	timestamps are missing

Em Thu, Dec 09, 2010 at 02:58:10PM +0100, Thomas Gleixner escreveu:
> On Thu, 9 Dec 2010, Ian Munsie wrote:
> > Excerpts from Thomas Gleixner's message of Tue Dec 07 12:49:04 UTC 2010:
> > > Allow the session client to specify that event ordering should be
> > > stopped when not all events have time stamps.
> > 
> > >  	/* These events are processed right away */
> > >  	switch (event->header.type) {
> > >  	case PERF_RECORD_HEADER_ATTR:
> > > -		return ops->attr(event, session);
> > > +		/* This updates session->sample_id_all */
> > > +		ret = ops->attr(event, session);
> > > +		/* Break ordering if sample_id_all is false */
> > > +		if (ops->ordering_requires_timestamps &&
> > > +		    ops->ordered_samples && !session->sample_id_all) {
> > > +			session->ordered_samples.next_flush = ULLONG_MAX;
> > > +			flush_sample_queue(session, ops);
> > > +			ops->ordered_samples = false;
> > > +		}
> > > +		return ret;
> > Since the fall back isn't triggered, not only are COMM and MMAP events
> > processed first (from patch 2 in this series), but EXIT will as well,
> > which causes no userspace events to be attributed.
> 
> So we need to check this in every event processing path? Or do we have
> for this kind of processing some other method which allows us to
> disable the ordered_samples bit once ?

FYI: I merged everything up to 8/9 and will push to Ingo soon, holler
if you disagree.

- Arnaldo
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