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| author | Adrian Hunter <adrian.hunter@intel.com> | 2020-05-28 14:08:58 +0200 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2020-05-28 16:33:36 +0200 |
| commit | 16b4b4e1a0038365a6734a4f50aba77e57865c8e (patch) | |
| tree | ac8d31c9239d8441cbb7193a6f7e711f6f89e6d9 /tools/perf/arch | |
| parent | perf script: Fix --call-trace for Intel PT (diff) | |
| download | linux-16b4b4e1a0038365a6734a4f50aba77e57865c8e.tar.xz linux-16b4b4e1a0038365a6734a4f50aba77e57865c8e.zip | |
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/arch')
| -rw-r--r-- | tools/perf/arch/arm/util/cs-etm.c | 3 | ||||
| -rw-r--r-- | tools/perf/arch/x86/util/intel-pt.c | 3 |
2 files changed, 4 insertions, 2 deletions
diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c index 607499b41bea..cea5e33d61d2 100644 --- a/tools/perf/arch/arm/util/cs-etm.c +++ b/tools/perf/arch/arm/util/cs-etm.c @@ -265,7 +265,8 @@ static int cs_etm_recording_options(struct auxtrace_record *itr, ptr->evlist = evlist; ptr->snapshot_mode = opts->auxtrace_snapshot_mode; - if (perf_can_record_switch_events()) + if (!record_opts__no_switch_events(opts) && + perf_can_record_switch_events()) opts->record_switch_events = true; evlist__for_each_entry(evlist, evsel) { diff --git a/tools/perf/arch/x86/util/intel-pt.c b/tools/perf/arch/x86/util/intel-pt.c index 0fe401ad3347..de69c8a34e15 100644 --- a/tools/perf/arch/x86/util/intel-pt.c +++ b/tools/perf/arch/x86/util/intel-pt.c @@ -787,7 +787,8 @@ static int intel_pt_recording_options(struct auxtrace_record *itr, * Per-cpu recording needs sched_switch events to distinguish different * threads. */ - if (have_timing_info && !perf_cpu_map__empty(cpus)) { + if (have_timing_info && !perf_cpu_map__empty(cpus) && + !record_opts__no_switch_events(opts)) { if (perf_can_record_switch_events()) { bool cpu_wide = !target__none(&opts->target) && !target__has_task(&opts->target); |