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authorNamhyung Kim <namhyung@kernel.org>2020-11-27 14:43:56 +0900
committerArnaldo Carvalho de Melo <acme@redhat.com>2020-11-27 14:26:33 -0300
commitaa50d953c169e876413bf237319e728dd41d9fdd (patch)
treefa9c4a13d6afe0e912ecc6226005398c01044da4 /tools/perf/util/synthetic-events.c
parent9713070028b9ab317f395ee130fa2c4ea741bab4 (diff)
downloadlinux-stericsson-aa50d953c169e876413bf237319e728dd41d9fdd.tar.gz
perf record: Synthesize cgroup events only if needed
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@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Jiri Olsa <jolsa@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lore.kernel.org/lkml/20201127054356.405481-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/synthetic-events.c')
-rw-r--r--tools/perf/util/synthetic-events.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
index 8a23391558cf..d9c624377da7 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;