perf record: Create events initially disabled and enable after init
perf-record currently creates events enabled. When doing a system wide collection (-a arg) this causes data collection for perf's initialization activities -- eg., perf_event__synthesize_threads(). For some events (e.g., context switch S/W event or tracepoints like syscalls) perf's initialization causes a lot of events to be captured frequently generating "Check IO/CPU overload!" warnings on larger systems (e.g., 2 socket, quad core, hyperthreading). perf's initialization phase can be skipped by creating events disabled and then enabling them once the initialization is done. Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1314289075-14706-1-git-send-email-dsahern@gmail.com Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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committed by
Arnaldo Carvalho de Melo
parent
694bf407b0
commit
764e16a30a
@@ -161,6 +161,7 @@ static void config_attr(struct perf_evsel *evsel, struct perf_evlist *evlist)
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struct perf_event_attr *attr = &evsel->attr;
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int track = !evsel->idx; /* only the first counter needs these */
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attr->disabled = 1;
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attr->inherit = !no_inherit;
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attr->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED |
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PERF_FORMAT_TOTAL_TIME_RUNNING |
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@@ -671,6 +672,8 @@ static int __cmd_record(int argc, const char **argv)
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}
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}
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perf_evlist__enable(evsel_list);
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/*
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* Let the child rip
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*/
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