From: Namhyung Kim <namhyung@kernel.org>
Date: Thu, 27 May 2021 18:28:35 +0000 (-0700)
Subject: perf record: Move probing cgroup sampling support
X-Git-Tag: v5.15~1019^2~6
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4f2abe91922ba02bb419d91d92a518e4c805220b;p=platform%2Fkernel%2Flinux-starfive.git

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: Namhyung 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: Arnaldo Carvalho de Melo <acme@redhat.com>
---

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 3337b5f..84803ab 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -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;
 
diff --git a/tools/perf/util/perf_api_probe.c b/tools/perf/util/perf_api_probe.c
index 829af17..0204116 100644
--- a/tools/perf/util/perf_api_probe.c
+++ b/tools/perf/util/perf_api_probe.c
@@ -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);
+}
diff --git a/tools/perf/util/perf_api_probe.h b/tools/perf/util/perf_api_probe.h
index f12ca55..b104168 100644
--- a/tools/perf/util/perf_api_probe.h
+++ b/tools/perf/util/perf_api_probe.h
@@ -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