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 16:55:32 -0200 [thread overview]
Message-ID: <20120130185532.GC15935@infradead.org> (raw)
In-Reply-To: <1327827356-8786-1-git-send-email-namhyung@gmail.com>
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?
Do you see any problem with not checking the header type?
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
> Signed-off-by: Namhyung Kim <namhyung@gmail.com>
> ---
> tools/perf/builtin-top.c | 8 ++++++++
> 1 files changed, 8 insertions(+), 0 deletions(-)
>
> diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
> index e8b033c074f9..f68fba52c8d8 100644
> --- a/tools/perf/builtin-top.c
> +++ b/tools/perf/builtin-top.c
> @@ -771,6 +771,14 @@ static void perf_top__mmap_read_idx(struct perf_top *top, int idx)
> }
>
> evsel = perf_evlist__id2evsel(session->evlist, sample.id);
> + if (evsel == NULL && !session->sample_id_all &&
> + event->header.type != PERF_RECORD_SAMPLE) {
> + /*
> + * Old kernel, no sample_id_all field.
> + * Just use active evsel.
> + */
> + evsel = top->sym_evsel;
> + }
> assert(evsel != NULL);
>
> origin = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
> --
> 1.7.8.2
next prev parent reply other threads:[~2012-01-30 18:55 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 ` Arnaldo Carvalho de Melo [this message]
2012-01-31 0:31 ` [PATCH 1/5] perf top: Use active evsel for non-sample events on old kernel Namhyung Kim
2012-01-31 0:34 ` Arnaldo Carvalho de Melo
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