From: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
To: Namhyung Kim <namhyung@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/5] perf top: Use active evsel for non-sample events on old kernel
Date: Mon, 30 Jan 2012 22:34:23 -0200 [thread overview]
Message-ID: <20120131003423.GA25293@infradead.org> (raw)
In-Reply-To: <4F273651.2020908@gmail.com>
Em Tue, Jan 31, 2012 at 09:31:13AM +0900, Namhyung Kim escreveu:
> 2012-01-31 3:55 AM, Arnaldo Carvalho de Melo wrote:
> >Em Sun, Jan 29, 2012 at 05:55:52PM +0900, Namhyung Kim escreveu:
> >>If multiple events are specified on old kernel,
> >>perf_evlist__id2evsel() returns NULL for non-sampling events
> >>since the sample.id doesn't contain valid value, and it triggers
> >>assert below. If only one event is given, the function returns
> >>the evsel regardless of sample.id, this is why most case cause
> >>no problem on old kernel.
> >>
> >>Fix it by using active evsel.
> >
> >How about this one instead:
> >
> >diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> >index a6d50e3..3ffb320 100644
> >--- a/tools/perf/util/evlist.c
> >+++ b/tools/perf/util/evlist.c
> >@@ -349,6 +349,10 @@ struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id)
> > hlist_for_each_entry(sid, pos, head, node)
> > if (sid->id == id)
> > return sid->evsel;
> >+
> >+ if (!perf_evlist__sample_id_all(evlist))
> >+ return list_entry(evlist->entries.next, struct perf_evsel, node);
> >+
> > return NULL;
> > }
> >
> >That way we won't have to patch other tools that would get the same
> >problem in such new tool/old kernel combos, right?
> >
>
> Right, looks good to me.
Please resend that way and I'll apply, or lemme know if you prefer for
me to do it and just stick your 'Acked-by: ' or 'Tested-by:' on it.
>
> >Do you see any problem with not checking the header type?
> >
>
> No, I don't, at least for now :)
>
>
> >Also please try to avoid using perf_session fields, prefer to use
> >perf_{evlist,evsel} when possible, in this case you could use
> >perf_evlist__sample_id_all(evlist), for instance.
> >
> >- Arnaldo
> >
>
> OK, will do that later.
>
> Thanks,
> Namhyung
prev parent reply other threads:[~2012-01-31 0:34 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-29 8:55 [PATCH 1/5] perf top: Use active evsel for non-sample events on old kernel Namhyung Kim
2012-01-29 8:55 ` [PATCH 2/5] perf record: Add error message for EMFILE Namhyung Kim
2012-01-29 15:28 ` David Ahern
2012-01-30 1:09 ` Namhyung Kim
[not found] ` <CAKYOsXxxmG8xQfPcn9xW+Dzd_-Qo8jUv8071UHdC18RBatq=uw@mail.gmail.com>
2012-01-30 18:56 ` Arnaldo Carvalho de Melo
2012-01-29 8:55 ` [PATCH 3/5] perf stat: " Namhyung Kim
2012-01-29 8:55 ` [PATCH 4/5] perf tools: Remove unnecessary ctype.h inclusion Namhyung Kim
2012-01-31 13:22 ` [tip:perf/core] " tip-bot for Namhyung Kim
2012-01-29 8:55 ` [PATCH 5/5] perf lock: Document lock info subcommand Namhyung Kim
2012-01-31 13:21 ` [tip:perf/core] " tip-bot for Namhyung Kim
2012-01-30 18:55 ` [PATCH 1/5] perf top: Use active evsel for non-sample events on old kernel Arnaldo Carvalho de Melo
2012-01-31 0:31 ` Namhyung Kim
2012-01-31 0:34 ` Arnaldo Carvalho de Melo [this message]
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