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| author | Adrian Hunter <adrian.hunter@intel.com> | 2020-05-28 15:08:58 +0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2020-05-28 11:33:36 -0300 |
| commit | 16b4b4e1a0038365a6734a4f50aba77e57865c8e (patch) | |
| tree | ac8d31c9239d8441cbb7193a6f7e711f6f89e6d9 /tools/perf/builtin-record.c | |
| parent | b51640854df12c361719ea1d8bdcf026009bd89d (diff) | |
| download | linux-16b4b4e1a0038365a6734a4f50aba77e57865c8e.tar.bz2 | |
perf record: Respect --no-switch-events
Context switch events are added automatically by Intel PT and Coresight.
Make it possible to suppress them. That is useful for tracing the
scheduler without the disturbance that the switch event processing
creates.
Example:
Prerequisites:
$ which perf
~/bin/perf
$ sudo setcap "cap_sys_rawio,cap_sys_admin,cap_sys_ptrace,cap_syslog,cap_ipc_lock=ep" ~/bin/perf
$ sudo chmod +r /proc/kcore
Before:
$ perf record --no-switch-events --kcore -a -e intel_pt//k -- sleep 0.001
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.938 MB perf.data ]
$ perf script -D | grep PERF_RECORD_SWITCH | wc -l
572
After:
$ perf record --no-switch-events --kcore -a -e intel_pt//k -- sleep 0.001
Warning:
Intel Processor Trace decoding will not be possible except for kernel tracing!
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.838 MB perf.data ]
$ perf script -D | grep PERF_RECORD_SWITCH | wc -l
0
$ sudo chmod go-r /proc/kcore
$ sudo setcap -r ~/bin/perf
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: http://lore.kernel.org/lkml/20200528120859.21604-1-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/builtin-record.c')
| -rw-r--r-- | tools/perf/builtin-record.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index c69f16361958..ecd478a22c64 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -2501,8 +2501,9 @@ static struct option __record_options[] = { "Record namespaces events"), OPT_BOOLEAN(0, "all-cgroups", &record.opts.record_cgroup, "Record cgroup events"), - OPT_BOOLEAN(0, "switch-events", &record.opts.record_switch_events, - "Record context switch events"), + OPT_BOOLEAN_SET(0, "switch-events", &record.opts.record_switch_events, + &record.opts.record_switch_events_set, + "Record context switch events"), OPT_BOOLEAN_FLAG(0, "all-kernel", &record.opts.all_kernel, "Configure all used events to run in kernel space.", PARSE_OPT_EXCLUSIVE), |