From: Namhyung Kim <namhyung@xxxxxxxxxx>
[ Upstream commit aa50d953c169e876413bf237319e728dd41d9fdd ]
It didn't check the tool->cgroup_events bit which is set when the
--all-cgroups option is given. Without it, samples will not have cgroup
info so no reason to synthesize.
We can check the PERF_RECORD_CGROUP records after running perf record
*WITHOUT* the --all-cgroups option:
Before:
$ perf report -D | grep CGROUP
0 0 0x8430 [0x38]: PERF_RECORD_CGROUP cgroup: 1 /
CGROUP events: 1
CGROUP events: 0
CGROUP events: 0
After:
$ perf report -D | grep CGROUP
CGROUP events: 0
CGROUP events: 0
CGROUP events: 0
Committer testing:
Before:
# perf record -a sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 2.208 MB perf.data (10003 samples) ]
# perf report -D | grep "CGROUP events"
CGROUP events: 146
CGROUP events: 0
CGROUP events: 0
#
After:
# perf record -a sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 2.208 MB perf.data (10448 samples) ]
# perf report -D | grep "CGROUP events"
CGROUP events: 0
CGROUP events: 0
CGROUP events: 0
#
With all-cgroups:
# perf record --all-cgroups -a sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 2.374 MB perf.data (11526 samples) ]
# perf report -D | grep "CGROUP events"
CGROUP events: 146
CGROUP events: 0
CGROUP events: 0
#
Fixes: 8fb4b67939e16 ("perf record: Add --all-cgroups option")
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Link: http://lore.kernel.org/lkml/20201127054356.405481-1-namhyung@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
tools/perf/util/synthetic-events.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
index 89b390623b63d..54ca751a2b3b3 100644
--- a/tools/perf/util/synthetic-events.c
+++ b/tools/perf/util/synthetic-events.c
@@ -563,6 +563,9 @@ int perf_event__synthesize_cgroups(struct perf_tool *tool,
char cgrp_root[PATH_MAX];
size_t mount_len; /* length of mount point in the path */
+ if (!tool || !tool->cgroup_events)
+ return 0;
+
if (cgroupfs_find_mountpoint(cgrp_root, PATH_MAX, "perf_event") < 0) {
pr_debug("cannot find cgroup mount point\n");
return -1;
--
2.27.0
