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| author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2018-03-01 13:46:23 -0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2018-03-05 09:58:43 -0300 |
| commit | 67230479b2304be99e9451ee171aa288a112ea16 (patch) | |
| tree | ef8566f22145f433806f62fc7eaf7817cea486a5 /tools/perf/perf.h | |
| parent | 4f67336870f641daa485ea504777486e24a9aece (diff) | |
perf record: Allow asking for the maximum allowed sample rate
Add the handy '-F max' shortcut to reading and using the
kernel.perf_event_max_sample_rate value as the user supplied
sampling frequency:
# perf record -F max sleep 1
info: Using a maximum frequency rate of 15,000 Hz
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.019 MB perf.data (14 samples) ]
# sysctl kernel.perf_event_max_sample_rate
kernel.perf_event_max_sample_rate = 15000
# perf evlist -v
cycles:ppp: size: 112, { sample_period, sample_freq }: 15000, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1
# perf record -F 10 sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.019 MB perf.data (4 samples) ]
# perf evlist -v
cycles:ppp: size: 112, { sample_period, sample_freq }: 10, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1
#
Suggested-by: Ingo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-4y0tiuws62c64gp4cf0hme0m@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/perf.h')
| -rw-r--r-- | tools/perf/perf.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/tools/perf/perf.h b/tools/perf/perf.h index cfe46236a5e5..a5df8bf73a68 100644 --- a/tools/perf/perf.h +++ b/tools/perf/perf.h @@ -82,4 +82,6 @@ struct record_opts { struct option; extern const char * const *record_usage; extern struct option *record_options; + +int record__parse_freq(const struct option *opt, const char *str, int unset); #endif |