[PATCH v6 4/5] perf stat: Save aggr value to first member of prev_raw_counts

Jin Yao
2020-05-20T04:29:57Z

To collect the overall statistics for interval mode, we copy the
counts from evsel->prev_raw_counts to evsel->counts.

For AGGR_GLOBAL mode, because the perf_stat_process_counter creates
aggr values from per cpu values, but the per cpu values are 0,
so the calculated aggr values will be always 0.

This patch uses a trick that saves the previous aggr value to
the first member of perf_counts, then aggr calculation in
process_counter_values can work correctly for AGGR_GLOBAL.

v6:
---
Add comments in perf_evlist__save_aggr_prev_raw_counts.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
---
tools/perf/util/stat.c | 20 ++++++++++++++++++++
tools/perf/util/stat.h | 1 +
2 files changed, 21 insertions(+)

diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
index aadc723ce871..d23109c9bee9 100644
--- a/tools/perf/util/stat.c
+++ b/tools/perf/util/stat.c
@@ -249,6 +249,26 @@ void perf_evlist__copy_prev_raw_counts(struct evlist *evlist)
perf_evsel__copy_prev_raw_counts(evsel);
}

+void perf_evlist__save_aggr_prev_raw_counts(struct evlist *evlist)
+{
+ struct evsel *evsel;
+
+ /*
+ * To collect the overall statistics for interval mode,
+ * we copy the counts from evsel->prev_raw_counts to
+ * evsel->counts. The perf_stat_process_counter creates
+ * aggr values from per cpu values, but the per cpu values
+ * are 0 for AGGR_GLOBAL. So we use a trick that saves the
+ * previous aggr value to the first member of perf_counts,
+ * then aggr calculation in process_counter_values can work
+ * correctly.
+ */
+ evlist__for_each_entry(evlist, evsel) {
+ *perf_counts(evsel->prev_raw_counts, 0, 0) =
+ evsel->prev_raw_counts->aggr;
+ }
+}
+
static void zero_per_pkg(struct evsel *counter)
{
if (counter->per_pkg_mask)
diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
index 62cf72c71869..18ead55756cc 100644
--- a/tools/perf/util/stat.h
+++ b/tools/perf/util/stat.h
@@ -199,6 +199,7 @@ void perf_evlist__free_stats(struct evlist *evlist);
void perf_evlist__reset_stats(struct evlist *evlist);
void perf_evlist__reset_prev_raw_counts(struct evlist *evlist);
void perf_evlist__copy_prev_raw_counts(struct evlist *evlist);
+void perf_evlist__save_aggr_prev_raw_counts(struct evlist *evlist);

int perf_stat_process_counter(struct perf_stat_config *config,
struct evsel *counter);
--
2.17.1