Changing the way we retrieve the event ID. Instead of parsing out
the ID out of the read data, using the PERF_EVENT_IOC_ID ioctl.
Keeping the old way in place to support kernels without
PERF_EVENT_IOC_ID ioctl support.
This will be useful for retrieving the event ID for events
with PERF_FORMAT_GROUP read format set, where it's impossible
to get correct event id out of the read call data.
Signed-off-by: Jiri Olsa <jo...@redhat.com>
Cc: Arnaldo Carvalho de Melo <a...@ghostprotocols.net>
Cc: Peter Zijlstra <a.p.zijls...@chello.nl>
Cc: Ingo Molnar <mi...@elte.hu>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Corey Ashford <cjash...@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: Namhyung Kim <namhy...@kernel.org>
---
tools/perf/util/evlist.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index eddd5eb..51e21f9 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -298,6 +298,17 @@ static int perf_evlist__id_add_fd(struct perf_evlist
*evlist,
{
u64 read_data[4] = { 0, };
int id_idx = 1; /* The first entry is the counter value */
+ u64 id;
+ int ret;
+
+ ret = ioctl(fd, PERF_EVENT_IOC_ID, &id);
+ if (!ret)
+ goto add;
+
+ if (errno != ENOTTY)
+ return -1;
+
+ /* Legacy way to get event id.. All hail to old kernels! */
if (!(evsel->attr.read_format & PERF_FORMAT_ID) ||
read(fd, &read_data, sizeof(read_data)) == -1)
@@ -308,7 +319,10 @@ static int perf_evlist__id_add_fd(struct perf_evlist
*evlist,
if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
++id_idx;
- perf_evlist__id_add(evlist, evsel, cpu, thread, read_data[id_idx]);
+ id = read_data[id_idx];
+
+ add:
+ perf_evlist__id_add(evlist, evsel, cpu, thread, id);
return 0;
}
--
1.7.11.7
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