Commit 4f2abe91 authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
Browse files

perf record: Move probing cgroup sampling support 



I found that checking cgroup sampling support using the missing features
doesn't work on old kernels.  Because it added both attr.cgroup bit and
PERF_SAMPLE_CGROUP bit, it needs to check whichever comes first (usually
the actual event, not dummy).

But it only checks the attr.cgroup bit which is set only in the dummy
event so cannot detect failtures due the sample bits.  Also we don't
ignore the missing feature and retry, it'd be better checking it with
the API probing logic.

Committer notes:

Extracted the minimal part to check using the new cgroup API probe
routine, the part that removes the cgroup member can be left for further
discussion.

Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210527182835.1634339-1-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 3cb17cce

tools/perf/builtin-record.c

+6 −0
Original line number Diff line number Diff line
@@ -2714,6 +2714,12 @@ int cmd_record(int argc, const char **argv) 
		rec->no_buildid = true;

	}



	if (rec->opts.record_cgroup && !perf_can_record_cgroup()) {

		pr_err("Kernel has no cgroup sampling support.\n");

		err = -EINVAL;

		goto out_opts;

	}



	if (rec->opts.kcore)

		rec->data.is_dir = true;

tools/perf/util/perf_api_probe.c

+10 −0
Original line number Diff line number Diff line
@@ -103,6 +103,11 @@ static void perf_probe_build_id(struct evsel *evsel) 
	evsel->core.attr.build_id = 1;

}



static void perf_probe_cgroup(struct evsel *evsel)

{

	evsel->core.attr.cgroup = 1;

}



bool perf_can_sample_identifier(void)

{

	return perf_probe_api(perf_probe_sample_identifier);
@@ -182,3 +187,8 @@ bool perf_can_record_build_id(void) 
{

	return perf_probe_api(perf_probe_build_id);

}



bool perf_can_record_cgroup(void)

{

	return perf_probe_api(perf_probe_cgroup);

}

tools/perf/util/perf_api_probe.h

+1 −0
Original line number Diff line number Diff line
@@ -12,5 +12,6 @@ bool perf_can_record_switch_events(void); 
bool perf_can_record_text_poke_events(void);

bool perf_can_sample_identifier(void);

bool perf_can_record_build_id(void);

bool perf_can_record_cgroup(void);



#endif // __PERF_API_PROBE_H