From 764e16a30a77a9c8346fbae6615e7c818ce9d00f Mon Sep 17 00:00:00 2001 From: David Ahern Date: Thu, 25 Aug 2011 10:17:55 -0600 Subject: 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 Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1314289075-14706-1-git-send-email-dsahern@gmail.com Signed-off-by: David Ahern Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evlist.c | 13 +++++++++++++ tools/perf/util/evlist.h | 1 + 2 files changed, 14 insertions(+) (limited to 'tools/perf/util') diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index c12bd476c6f..72e9f4886b6 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -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; diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h index ce85ae9ae57..f3491500274 100644 --- a/tools/perf/util/evlist.h +++ b/tools/perf/util/evlist.h @@ -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, -- cgit v1.2.3-70-g09d2