From: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
To: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>,
a.p.zijlstra@chello.nl, mingo@elte.hu,
Stephane Eranian <eranian@google.com>,
paulus@samba.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf tools: Exit recording if events have non matching sample type
Date: Thu, 29 Sep 2011 23:21:34 -0300 [thread overview]
Message-ID: <20110930022134.GB9369@ghostprotocols.net> (raw)
In-Reply-To: <4E85142C.101@gmail.com>
Em Thu, Sep 29, 2011 at 06:58:20PM -0600, David Ahern escreveu:
> On 09/29/2011 06:40 PM, Arnaldo Carvalho de Melo wrote:
> > This comes from time to time:
> >
> > http://us.generation-nt.com/answer/bug-perf-event-sampling-buffer-format-cannot-handle-multi-event-sampling-help-202985832.html
> >
> > The whole point of sample_type is to ask for just what is needed for
> > some specific event so that we reduce the per sample footprint.
> >
> > So we allow for multiple types of events to be on the same stream, but
> > not for them to have just what each need, its a limitation, one that we
> > can solve. I see no reason not to solve it :-)
> >
> > The evsel/evlist classes were designed to abstract away such details,
> > i.e. perf_evlist__mmap should notice different sample_types and sort
> > this out transparently.
> >
> > And then perf_evlist__mmap_read(evlist, idx), evlist->nr_mmaps should be
> > enough to process the events :-)
> >
> > - Arnaldo
>
> An ABI change fixes the root cause of the current problem -- put an id
> in perf_event_header. The id maps to the evsel which has the
> sample_type. Right now you have to parse the sample to get the id to get
> the evsel.
This id is not always needed, so it shouldn't go to perf_event_header.
Peter, can you comment here? ;-)
- Arnaldo
next prev parent reply other threads:[~2011-09-30 2:21 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-29 23:06 [PATCH] perf tools: Exit recording if events have non matching sample type Arnaldo Carvalho de Melo
2011-09-29 23:33 ` David Ahern
2011-09-30 0:40 ` Arnaldo Carvalho de Melo
2011-09-30 0:58 ` David Ahern
2011-09-30 2:21 ` Arnaldo Carvalho de Melo [this message]
2011-09-30 2:41 ` David Ahern
2011-09-30 7:39 ` Peter Zijlstra
2011-10-04 4:14 ` David Ahern
2011-10-04 10:00 ` Peter Zijlstra
2011-10-04 13:41 ` Arnaldo Carvalho de Melo
-- strict thread matches above, loose matches on Subject: below --
2011-09-29 16:01 Jiri Olsa
2011-09-29 22:05 ` Arnaldo Carvalho de Melo
2011-09-29 22:55 ` David Ahern
2011-10-03 10:22 ` Jiri Olsa
2011-10-03 16:27 ` Arnaldo Carvalho de Melo
2011-10-03 19:15 ` Jiri Olsa
2011-10-17 12:50 ` Jiri Olsa
2011-10-21 7:18 ` Xu, Anhua
2011-10-21 8:10 ` Jiri Olsa
2011-10-21 14:16 ` David Ahern
2011-10-21 14:29 ` David Ahern
2011-10-21 14:43 ` Jiri Olsa
2011-10-21 14:42 ` Jiri Olsa
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