[PATCH 9/9] perf stat: Display user and system time

[Jiri Olsa <jolsa@kernel.org>]

Adding the support to read rusage data once the
workload is finished and display the system/user
time values:

  $ perf stat --null ./perf bench sched pipe
  ...

   Performance counter stats for './perf bench sched pipe':

       5.342599256 seconds time elapsed

       2.544434000 seconds user
       4.549691000 seconds sys

It works only in non -r mode.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/n/tip-t8k6d3gs8sz8zqnz3aslk5ro@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/builtin-stat.c | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 2137c7d11767..9c987617c8e7 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -80,6 +80,9 @@
 #include <sys/stat.h>
 #include <sys/wait.h>
 #include <unistd.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/wait.h>
 
 #include "sane_ctype.h"
 
@@ -174,6 +177,8 @@ static const char		*output_name;
 static int			output_fd;
 static int			print_free_counters_hint;
 static u64			*walltime_run;
+static bool			ru_display			= false;
+static struct rusage		ru_data;
 
 struct perf_stat {
 	bool			 record;
@@ -725,7 +730,7 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx)
 					break;
 			}
 		}
-		waitpid(child_pid, &status, 0);
+		wait4(child_pid, &status, 0, &ru_data);
 
 		if (workload_exec_errno) {
 			const char *emsg = str_error_r(workload_exec_errno, msg, sizeof(msg));
@@ -1773,6 +1778,11 @@ static void print_table(FILE *output, int precision, double avg)
 	fprintf(output, "\n%*s# Final result:\n", indent, "");
 }
 
+static double timeval2double(struct timeval *t)
+{
+	return t->tv_sec + (double) t->tv_usec/USEC_PER_SEC;
+}
+
 static void print_footer(void)
 {
 	double avg = avg_stats(&walltime_nsecs_stats) / NSEC_PER_SEC;
@@ -1784,6 +1794,15 @@ static void print_footer(void)
 
 	if (run_count == 1) {
 		fprintf(output, " %17.9f seconds time elapsed", avg);
+
+		if (ru_display) {
+			double utime = timeval2double(&ru_data.ru_utime);
+			double stime = timeval2double(&ru_data.ru_stime);
+
+			fprintf(output, "\n\n");
+			fprintf(output, " %17.9f seconds user\n", utime);
+			fprintf(output, " %17.9f seconds sys\n", stime);
+		}
 	} else {
 		double sd = stddev_stats(&walltime_nsecs_stats) / NSEC_PER_SEC;
 		/*
@@ -2869,6 +2888,13 @@ int cmd_stat(int argc, const char **argv)
 		goto out;
 	}
 
+	/*
+	 * Display user/system times only for single
+	 * run and when there's specified tracee.
+	 */
+	if ((run_count == 1) && target__none(&target))
+		ru_display = true;
+
 	if (output_fd < 0) {
 		fprintf(stderr, "argument to --log-fd must be a > 0\n");
 		parse_options_usage(stat_usage, stat_options, "log-fd", 0);
-- 
2.13.6