perf_evlist__toggle_paused() is introduced to pause/resume events in an evlist. Utilize PERF_EVENT_IOC_PAUSE_OUTPUT ioctl. Following commits use perf_evlist__toggle_paused() to ensure overwrite ring buffer is paused before reading.
Signed-off-by: Wang Nan <[email protected]> Signed-off-by: He Kuang <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Zefan Li <[email protected]> Cc: [email protected] --- tools/perf/util/evlist.c | 22 ++++++++++++++++++++++ tools/perf/util/evlist.h | 1 + 2 files changed, 23 insertions(+) diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index 1a370db..f4bb8be 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -679,6 +679,28 @@ static struct perf_evsel *perf_evlist__event2evsel(struct perf_evlist *evlist, return NULL; } +int perf_evlist__toggle_paused(struct perf_evlist *evlist, bool pause) +{ + int i; + + for (i = 0; i < evlist->nr_mmaps; i++) { + int fd = evlist->mmap[i].fd; + int err; + + if (fd < 0) + continue; + err = ioctl(fd, PERF_EVENT_IOC_PAUSE_OUTPUT, + pause ? 1 : 0); + if (err) { + err = (errno == 0 ? -EINVAL : -errno); + pr_err("Unable to pause output on %d: %s\n", + fd, strerror(-err)); + return err; + } + } + return 0; +} + /* When check_messup is true, 'end' must points to a good entry */ static union perf_event * perf_mmap__read(struct perf_mmap *md, bool check_messup, u64 start, diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h index 0d165b1..13234dc 100644 --- a/tools/perf/util/evlist.h +++ b/tools/perf/util/evlist.h @@ -136,6 +136,7 @@ void perf_evlist__mmap_read_catchup(struct perf_evlist *evlist, int idx); void perf_evlist__mmap_consume(struct perf_evlist *evlist, int idx); +int perf_evlist__toggle_paused(struct perf_evlist *evlist, bool pause); int perf_evlist__open(struct perf_evlist *evlist); void perf_evlist__close(struct perf_evlist *evlist); -- 1.8.3.4
