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Commit de63403b authored by Jiri Olsa's avatar Jiri Olsa Committed by Arnaldo Carvalho de Melo
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perf tools: Add perf_evsel__read_size function 



Currently we use the size of struct perf_counts_values to read the
event, which prevents us to put any new member to the struct.

Adding perf_evsel__read_size to return size of the buffer needed for
event read.

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20170726120206.9099-2-jolsa@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent ee438ec8

tools/perf/util/evsel.c

+28 −1
Original line number Diff line number Diff line
@@ -1261,15 +1261,42 @@ void perf_counts_values__scale(struct perf_counts_values *count, 
		*pscaled = scaled;

}



static int perf_evsel__read_size(struct perf_evsel *evsel)

{

	u64 read_format = evsel->attr.read_format;

	int entry = sizeof(u64); /* value */

	int size = 0;

	int nr = 1;



	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)

		size += sizeof(u64);



	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)

		size += sizeof(u64);



	if (read_format & PERF_FORMAT_ID)

		entry += sizeof(u64);



	if (read_format & PERF_FORMAT_GROUP) {

		nr = evsel->nr_members;

		size += sizeof(u64);

	}



	size += entry * nr;

	return size;

}



int perf_evsel__read(struct perf_evsel *evsel, int cpu, int thread,

		     struct perf_counts_values *count)

{

	size_t size = perf_evsel__read_size(evsel);



	memset(count, 0, sizeof(*count));



	if (FD(evsel, cpu, thread) < 0)

		return -EINVAL;



	if (readn(FD(evsel, cpu, thread), count, sizeof(*count)) <= 0)

	if (readn(FD(evsel, cpu, thread), count->values, size) <= 0)

		return -errno;



	return 0;