Messages in this thread Patch in this message | | | From | Arnaldo Carvalho de Melo <> | Subject | [PATCH 10/15] perf tools: Fix broken number of samples for perf report -n | Date | Thu, 6 Oct 2011 14:22:33 -0300 |
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From: Stephane Eranian <eranian@google.com>
The perf report -n option was broken because it was not reporting the correct number of samples depending on the sorting mode. By default, samples are sorted by comm,dso,sym. That means that samples for the same command (binary) get collapsed.
The hists__collapse_insert_entry() had a bug whereby it was aggregating the number of events observed (periods) but not the number of samples. Consequently, the number of samples reported could be below reality. The percentage remained correct because based on the periods.
This patch fixes the problem by also aggregating the number of samples. Here is an example:
$ perf report -n --stdio 12.38% 842 pong [kernel.kallsyms] [k] __lock_acquire
Here pong (a ctxsw stress test), is the only program running and thus it is the only one responsible for the lock_acquire samples.
If we change the sorting mode:
$ perf report -n --stdio --sort=sym 12.38% 1732 [k] __lock_acquire
The actual number of samples is shown.
With the fix:
$ perf report -n --stdio 12.38% 1732 pong [kernel.kallsyms] [k] __lock_acquire
Cc: David Ahern <dsahern@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20111003093815.GA6393@quad Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> --- tools/perf/util/hist.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c index 82138a2..c83e458 100644 --- a/tools/perf/util/hist.c +++ b/tools/perf/util/hist.c @@ -279,6 +279,7 @@ static bool hists__collapse_insert_entry(struct hists *hists, if (!cmp) { iter->period += he->period; + iter->nr_events += he->nr_events; if (symbol_conf.use_callchain) { callchain_cursor_reset(&hists->callchain_cursor); callchain_merge(&hists->callchain_cursor, iter->callchain, -- 1.6.2.5
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