perf_evlist__toggle_{pause,resume}() are introduced to pause/resume
events in an evlist. Utilize PERF_EVENT_IOC_PAUSE_OUTPUT ioctl.
Following commits use them to ensure overwrite ring buffer is paused
before reading.
Signed-off-by: Wang Nan <wangn...@huawei.com>
Signed-off-by: He Kuang <heku...@huawei.com>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: Jiri Olsa <jo...@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Zefan Li <lize...@huawei.com>
Cc: pi3or...@163.com
---
tools/perf/util/evlist.c | 32 ++++++++++++++++++++++++++++++++
tools/perf/util/evlist.h | 2 ++
2 files changed, 34 insertions(+)
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 1a370db..9303525 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -679,6 +679,38 @@ static struct perf_evsel *perf_evlist__event2evsel(struct
perf_evlist *evlist,
return NULL;
}
+static int perf_evlist__set_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;
+}
+
+int perf_evlist__pause(struct perf_evlist *evlist)
+{
+ return perf_evlist__set_paused(evlist, true);
+}
+
+int perf_evlist__resume(struct perf_evlist *evlist)
+{
+ return perf_evlist__set_paused(evlist, false);
+}
+
/* 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..97090b7 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -136,6 +136,8 @@ 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__pause(struct perf_evlist *evlist);
+int perf_evlist__resume(struct perf_evlist *evlist);
int perf_evlist__open(struct perf_evlist *evlist);
void perf_evlist__close(struct perf_evlist *evlist);
--
1.8.3.4
