Messages in this thread |  | | From | Namhyung Kim <> | Date | Mon, 30 Nov 2020 22:26:58 +0900 | Subject | Re: [PATCH] perf record: Synthesize cgroup events only if needed |
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Hi Jiri,
On Sat, Nov 28, 2020 at 12:46 AM Jiri Olsa <jolsa@redhat.com> wrote: > > 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
Actually I just copied the namespace code. :). It's only called from perf record and top, and neither of them pass NULL.
> > Acked-by: Jiri Olsa <jolsa@redhat.com>
Thanks, Namhyung
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