perf record: Create events initially disabled and enable after init (764e16a3) · Commits · 戴 / test

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>

tools/perf/builtin-record.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -161,6 +161,7 @@ static void config_attr(struct perf_evsel evsel, struct perf_evlist evlist)
		struct perf_event_attr *attr = &evsel->attr;
		int track = !evsel->idx; /* only the first counter needs these */

		attr->disabled = 1;
		attr->inherit = !no_inherit;
		attr->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED \|
		PERF_FORMAT_TOTAL_TIME_RUNNING \|
		@@ -671,6 +672,8 @@ static int __cmd_record(int argc, const char **argv)
		}
		}

		perf_evlist__enable(evsel_list);

		/*
		* Let the child rip
		*/

tools/perf/util/evlist.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -113,6 +113,19 @@ void perf_evlist__disable(struct perf_evlist *evlist)
		}
		}

		void perf_evlist__enable(struct perf_evlist *evlist)
		{
		int cpu, thread;
		struct perf_evsel *pos;

		for (cpu = 0; cpu < evlist->cpus->nr; cpu++) {
		list_for_each_entry(pos, &evlist->entries, node) {
		for (thread = 0; thread < evlist->threads->nr; thread++)
		ioctl(FD(pos, cpu, thread), PERF_EVENT_IOC_ENABLE);
		}
		}
		}

		int perf_evlist__alloc_pollfd(struct perf_evlist *evlist)
		{
		int nfds = evlist->cpus->nr * evlist->threads->nr * evlist->nr_entries;

tools/perf/util/evlist.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -54,6 +54,7 @@ int perf_evlist__mmap(struct perf_evlist *evlist, int pages, bool overwrite);
		void perf_evlist__munmap(struct perf_evlist *evlist);

		void perf_evlist__disable(struct perf_evlist *evlist);
		void perf_evlist__enable(struct perf_evlist *evlist);

		static inline void perf_evlist__set_maps(struct perf_evlist *evlist,
		struct cpu_map *cpus,

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