[PATCH 17/25] perf stat: Introduce perf_evsel__read function

[Jiri Olsa <jolsa@kernel.org>]

Adding simple read function that reads/store data
into given struct perf_counts_values *count object.

Link: http://lkml.kernel.org/n/tip-9r2zmzq0vkw8l300usq824sg@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/util/evsel.c | 14 ++++++++++++++
 tools/perf/util/evsel.h |  3 +++
 2 files changed, 17 insertions(+)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 1608e29ab83d..c1d210f8e799 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1060,6 +1060,20 @@ int perf_evsel__read_cb(struct perf_evsel *evsel, int cpu, int thread,
 	return cb(evsel, cpu, thread, &count);
 }
 
+int perf_evsel__read(struct perf_evsel *evsel, int cpu, int thread,
+		     struct perf_counts_values *count)
+{
+	memset(count, 0, sizeof(*count));
+
+	if (FD(evsel, cpu, thread) < 0)
+		return -EINVAL;
+
+	if (readn(FD(evsel, cpu, thread), count, sizeof(*count)) < 0)
+		return -errno;
+
+	return 0;
+}
+
 int __perf_evsel__read_on_cpu(struct perf_evsel *evsel,
 			      int cpu, int thread, bool scale)
 {
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 80929965f0f5..9609df91abc1 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -275,6 +275,9 @@ typedef int (perf_evsel__read_cb_t)(struct perf_evsel *evsel,
 int perf_evsel__read_cb(struct perf_evsel *evsel, int cpu, int thread,
 			perf_evsel__read_cb_t cb);
 
+int perf_evsel__read(struct perf_evsel *evsel, int cpu, int thread,
+		     struct perf_counts_values *count);
+
 int __perf_evsel__read_on_cpu(struct perf_evsel *evsel,
 			      int cpu, int thread, bool scale);
 
-- 
1.9.3