Messages in this thread |  | | Date | Fri, 27 Nov 2020 16:45:57 +0100 | From | Jiri Olsa <> | Subject | Re: [PATCH] perf record: Synthesize cgroup events only if needed |
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On Fri, Nov 27, 2020 at 02:43:56PM +0900, Namhyung Kim wrote: > 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 > > Fixes: 8fb4b67939e16 ("perf record: Add --all-cgroups option") > Signed-off-by: Namhyung Kim <namhyung@kernel.org> > --- > 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 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;
can !tool actually happen here? or it's just being extra cautious
Acked-by: Jiri Olsa <jolsa@redhat.com>
thanks, jirka
> + > if (cgroupfs_find_mountpoint(cgrp_root, PATH_MAX, "perf_event") < 0) { > pr_debug("cannot find cgroup mount point\n"); > return -1; > -- > 2.29.2.454.gaff20da3a2-goog >
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