linux-kernel - Re: [PATCH] perf tools: Exit recording if events have non matching sample type

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Message-ID: <20111003191543.GA2017@jolsa.Belkin>
Date:	Mon, 3 Oct 2011 21:15:43 +0200
From:	Jiri Olsa <jolsa@...hat.com>
To:	Arnaldo Carvalho de Melo <acme@...hat.com>
Cc:	a.p.zijlstra@...llo.nl, mingo@...e.hu, paulus@...ba.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] perf tools: Exit recording if events have non matching
 sample type

On Mon, Oct 03, 2011 at 01:27:04PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Mon, Oct 03, 2011 at 12:22:35PM +0200, Jiri Olsa escreveu:
> > On Thu, Sep 29, 2011 at 07:05:48PM -0300, Arnaldo Carvalho de Melo wrote:
> > > Em Thu, Sep 29, 2011 at 06:01:08PM +0200, Jiri Olsa escreveu:
> > > > The event processing relies on all events having the same sample_type.
> > > > 
> > > > This is being checked when the session is being opened read only.
> > > > It also needs to be checked when we do record, since events could be
> > > > read during processing build IDs at the end of the record command.
> > > > 
> > > > If we process events with different sample_type the processing might
> > > > skip some events or hang.
> > > > 
> > > > Following command hangs on my setup:
> > > >   ./perf record -o perf.data -e ext4:ext4_mb_new_group_pa \
> > > >    -e LLC-loads -- date '+%F'
> > > > 
> > > > because hardware and tracepoint events have different sample type.
> > > > 
> > > > With the patch applied the record command displays
> > > > "Non matching sample_type" message and exits.
> > > 
> > > That is way too cryptic :-\
> > > 
> > > What is that makes the sample type not match in this case? Can we make
> > > it match instead?
> > > 
> > > This is something to be properly fixed by _allowing_ non matching sample
> > > types, the evsel/evlist abstractions are getting we close but not there
> > > yet, multiple files in a perf.data/ directory are needed.
> > > 
> > > Till then can you check if we can make it match or else just say that
> > > the mix of events is not yet supported, please collect them in different
> > > sessions or something along those lines?
> > > 
> > > - Arnaldo
> > hi,
> > thanks for comments..
> > I just was this got in the tip tree git://tesla.tglx.de/git/linux-2.6-tip
> > 
> > perf tools: Exit record if events have non matching sample type
> > commit 6f9a4869e15de8af2fd715af876bc3e6b00757a7
> > Author: Jiri Olsa <jolsa@...hat.com>
> > Date:   Thu Sep 29 19:49:50 2011 +0200
> > 
> > I've read the email trail.. I'll check the sources and try to come up
> > with something.. ;)
> 
> Couldn't understand, will check if the patch was already applied, if so,
> why bother commenting, right? :-)

I meant solving the 'sample_type issue' some other 'better' way,
probably along the lines you guys suggested.. ;)

jirka
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