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| author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2015-07-27 23:13:21 +0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2015-07-29 16:51:45 +0300 |
| commit | 58b32c1b538f2d197ce385d6a314e83f8b787021 (patch) | |
| tree | 279b5d0478e1e5e7af9f7f3127be341b81a29048 /tools/perf/python | |
| parent | 84576da2f72e51be63c5b63c0e297028fa7ac59f (diff) | |
| download | linux-58b32c1b538f2d197ce385d6a314e83f8b787021.tar.xz | |
perf python: Make twatch.py use soft dummy event, freq=0
To not sample, what we want are just the PERF_RECORD_ lifetime events
for threads, using the default, PERF_TYPE_HARDWARE +
PERF_COUNT_HW_CYCLES and freq=1 (the default), makes perf reenable
irq_vectors:local_timer_entry, disabling nohz, not good for some use
cases where all we want is to get notifications when threads comes and
goes...
Fix it by using PERF_TYPE_SOFTWARE (no counter rotation) and
PERF_COUNT_SW_DUMMY (created by Adrian so that we could have access to
those PERF_RECORD_ goodies).
Reported-by: Luiz Fernando Capitulino <lcapitulino@redhat.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jaroslav Skarvada <jskarvad@redhat.com>
Cc: Jeremy Eder <jeder@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-kfsijirfrs6xfhkcdxeoen06@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/python')
| -rwxr-xr-x | tools/perf/python/twatch.py | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/tools/perf/python/twatch.py b/tools/perf/python/twatch.py index 2225162ee1fc..b9d508336ae6 100755 --- a/tools/perf/python/twatch.py +++ b/tools/perf/python/twatch.py @@ -18,10 +18,20 @@ import perf def main(): cpus = perf.cpu_map() threads = perf.thread_map() - evsel = perf.evsel(task = 1, comm = 1, mmap = 0, + evsel = perf.evsel(type = perf.TYPE_SOFTWARE, + config = perf.COUNT_SW_DUMMY, + task = 1, comm = 1, mmap = 0, freq = 0, wakeup_events = 1, watermark = 1, sample_id_all = 1, sample_type = perf.SAMPLE_PERIOD | perf.SAMPLE_TID | perf.SAMPLE_CPU) + + """What we want are just the PERF_RECORD_ lifetime events for threads, + using the default, PERF_TYPE_HARDWARE + PERF_COUNT_HW_CYCLES & freq=1 + (the default), makes perf reenable irq_vectors:local_timer_entry, when + disabling nohz, not good for some use cases where all we want is to get + threads comes and goes... So use (perf.TYPE_SOFTWARE, perf_COUNT_SW_DUMMY, + freq=0) instead.""" + evsel.open(cpus = cpus, threads = threads); evlist = perf.evlist(cpus, threads) evlist.add(evsel) |