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| author | Waiman Long <Waiman.Long@hp.com> | 2013-10-18 16:38:48 +0200 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2013-10-21 22:36:25 +0200 |
| commit | 91e95617429cb272fd908b1928a1915b37b9655f (patch) | |
| tree | 630cd19ff34cf210a03924e92c711d6c51076e2d /tools/perf/util/machine.h | |
| parent | perf session: Separating data file properties from session (diff) | |
| download | linux-91e95617429cb272fd908b1928a1915b37b9655f.tar.xz linux-91e95617429cb272fd908b1928a1915b37b9655f.zip | |
perf report: Add --max-stack option to limit callchain stack scan
When callgraph data was included in the perf data file, it may take a
long time to scan all those data and merge them together especially if
the stored callchains are long and the perf data file itself is large,
like a Gbyte or so.
The callchain stack is currently limited to PERF_MAX_STACK_DEPTH (127).
This is a large value. Usually the callgraph data that developers are
most interested in are the first few levels, the rests are usually not
looked at.
This patch adds a new --max-stack option to perf-report to limit the
depth of callchain stack data to look at to reduce the time it takes for
perf-report to finish its processing. It trades the presence of trailing
stack information with faster speed.
The following table shows the elapsed time of doing perf-report on a
perf.data file of size 985,531,828 bytes.
--max_stack Elapsed Time Output data size
----------- ------------ ----------------
not set 88.0s 124,422,651
64 87.5s 116,303,213
32 87.2s 112,023,804
16 86.6s 94,326,380
8 59.9s 33,697,248
4 40.7s 10,116,637
-g none 27.1s 2,555,810
Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1382107129-2010-4-git-send-email-Waiman.Long@hp.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/machine.h')
| -rw-r--r-- | tools/perf/util/machine.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h index d44c09bdc45e..4c1f5d567f54 100644 --- a/tools/perf/util/machine.h +++ b/tools/perf/util/machine.h @@ -92,7 +92,8 @@ int machine__resolve_callchain(struct machine *machine, struct thread *thread, struct perf_sample *sample, struct symbol **parent, - struct addr_location *root_al); + struct addr_location *root_al, + int max_stack); /* * Default guest kernel is defined by parameter --guestkallsyms |