[PATCH v3 4/4] perf stat: Report summary for interval mode

[Jin Yao]

Currently perf-stat supports to print counts at regular interval (-I),
but it's not very easy for user to get the overall statistics.

The patch uses 'evsel->prev_raw_counts' to get counts for summary.
Copy the counts to 'evsel->counts' after printing the interval results.
Next, we just follow the non-interval processing.

Let's see some examples,

 root@kbl-ppc:~# perf stat -e cycles -I1000 --interval-count 2
 #           time             counts unit events
      1.000412064          2,281,114      cycles
      2.001383658          2,547,880      cycles

  Performance counter stats for 'system wide':

          4,828,994      cycles

        2.002860349 seconds time elapsed

 root@kbl-ppc:~# perf stat -e cycles,instructions -I1000 --interval-count 2
 #           time             counts unit events
      1.000389902          1,536,093      cycles
      1.000389902            420,226      instructions              #    0.27  insn per cycle
      2.001433453          2,213,952      cycles
      2.001433453            735,465      instructions              #    0.33  insn per cycle

  Performance counter stats for 'system wide':

          3,750,045      cycles
          1,155,691      instructions              #    0.31  insn per cycle

        2.003023361 seconds time elapsed

 root@kbl-ppc:~# perf stat -M CPI,IPC -I1000 --interval-count 2
 #           time             counts unit events
      1.000435121            905,303      inst_retired.any          #      2.9 CPI
      1.000435121          2,663,333      cycles
      1.000435121            914,702      inst_retired.any          #      0.3 IPC
      1.000435121          2,676,559      cpu_clk_unhalted.thread
      2.001615941          1,951,092      inst_retired.any          #      1.8 CPI
      2.001615941          3,551,357      cycles
      2.001615941          1,950,837      inst_retired.any          #      0.5 IPC
      2.001615941          3,551,044      cpu_clk_unhalted.thread

  Performance counter stats for 'system wide':

          2,856,395      inst_retired.any          #      2.2 CPI
          6,214,690      cycles
          2,865,539      inst_retired.any          #      0.5 IPC
          6,227,603      cpu_clk_unhalted.thread

        2.003403078 seconds time elapsed

 v3:
 ---
 Use evsel->prev_raw_counts for summary counts

 v2:
 ---
 Rebase to perf/core branch

Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
---
 tools/perf/builtin-stat.c | 16 ++++++++++++++--
 tools/perf/util/stat.c    |  2 +-
 tools/perf/util/stat.h    |  1 +
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 97ee941649e6..f67d6a50274e 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -334,7 +334,7 @@ static void read_counters(struct timespec *rs)
 		evlist__for_each_entry(evsel_list, counter) {
 			if (evsel__cpu_iter_skip(counter, cpu))
 				continue;
-			if (!counter->err) {
+			if (!counter->err && !stat_config.summary) {
 				counter->err = read_counter_cpu(counter, rs,
 								counter->cpu_iter - 1);
 			}
@@ -364,6 +364,7 @@ static void thread_stats_reset(struct perf_stat_config *config)
 static void process_interval(void)
 {
 	struct timespec ts, rs;
+	struct stats walltime_nsecs_stats_bak;
 
 	clock_gettime(CLOCK_MONOTONIC, &ts);
 	diff_timespec(&rs, &ts, &ref_time);
@@ -377,9 +378,11 @@ static void process_interval(void)
 			pr_err("failed to write stat round event\n");
 	}
 
+	walltime_nsecs_stats_bak = walltime_nsecs_stats;
 	init_stats(&walltime_nsecs_stats);
 	update_stats(&walltime_nsecs_stats, stat_config.interval * 1000000);
 	print_counters(&rs, 0, NULL);
+	walltime_nsecs_stats = walltime_nsecs_stats_bak;
 }
 
 static void enable_counters(void)
@@ -735,6 +738,15 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
 
 	update_stats(&walltime_nsecs_stats, t1 - t0);
 
+	if (interval) {
+		stat_config.interval = 0;
+		stat_config.summary = true;
+		perf_evlist__copy_prev_raw_counts(evsel_list);
+		perf_evlist__reset_prev_raw_counts(evsel_list);
+		thread_stats_reset(&stat_config);
+		perf_stat__reset_shadow_per_stat(&rt_stat);
+	}
+
 	/*
 	 * Closing a group leader splits the group, and as we only disable
 	 * group leaders, results in remaining events becoming enabled. To
@@ -2158,7 +2170,7 @@ int cmd_stat(int argc, const char **argv)
 		}
 	}
 
-	if (!forever && status != -1 && !interval)
+	if (!forever && status != -1 && (!interval || stat_config.summary))
 		print_counters(NULL, argc, argv);
 
 	if (STAT_RECORD) {
diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
index ede113805ecd..47b26c024830 100644
--- a/tools/perf/util/stat.c
+++ b/tools/perf/util/stat.c
@@ -393,7 +393,7 @@ int perf_stat_process_counter(struct perf_stat_config *config,
 	 * interval mode, otherwise overall avg running
 	 * averages will be shown for each interval.
 	 */
-	if (config->interval) {
+	if (config->interval || config->summary) {
 		for (i = 0; i < 3; i++)
 			init_stats(&ps->res_stats[i]);
 	}
diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
index 62cf72c71869..c60e9e5d6474 100644
--- a/tools/perf/util/stat.h
+++ b/tools/perf/util/stat.h
@@ -110,6 +110,7 @@ struct perf_stat_config {
 	bool			 all_kernel;
 	bool			 all_user;
 	bool			 percore_show_thread;
+	bool			 summary;
 	FILE			*output;
 	unsigned int		 interval;
 	unsigned int		 timeout;
-- 
2.17.1