[PATCH 37/46] perf stat: Display user and system time

Arnaldo Carvalho de Melo
2018-06-05T17:57:47Z

From: 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 and only for workload target.

So as of now, for workload targets, we display 3 types of timings. The
time we meassure in perf stat from enable to disable+period:

5.342599256 seconds time elapsed

The time spent in user and system lands, displayed only for workload
session/target:

2.544434000 seconds user
4.549691000 seconds sys

Those times are the very same displayed by 'time' tool. They are
returned by wait4 call via the getrusage struct interface.

Committer notes:

Had to rename some variables to avoid this on older systems such as
centos:6:

builtin-stat.c: In function 'print_footer':
builtin-stat.c:1831: warning: declaration of 'stime' shadows a global declaration
/usr/include/time.h:297: warning: shadowed declaration is here

Committer testing:

# perf stat --null time perf bench sched pipe
# Running 'sched/pipe' benchmark:
# Executed 1000000 pipe operations between two processes

Total time: 5.526 [sec]

5.526534 usecs/op
180945 ops/sec
1.00user 6.25system 0:05.52elapsed 131%CPU (0avgtext+0avgdata 8056maxresident)k
0inputs+0outputs (0major+606minor)pagefaults 0swaps

Performance counter stats for 'time perf bench sched pipe':

5.530978744 seconds time elapsed

1.004037000 seconds user
6.259937000 seconds sys

#

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180605121313.31337-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/Documentation/perf-stat.txt | 40 ++++++++++++++++++++++++----------
tools/perf/builtin-stat.c | 28 +++++++++++++++++++++++-
2 files changed, 56 insertions(+), 12 deletions(-)

diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index 3a822f308e6d..5dfe102fb5b5 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -310,20 +310,38 @@ Users who wants to get the actual value can apply --no-metric-only.
EXAMPLES
--------

-$ perf stat -- make -j
+$ perf stat -- make

- Performance counter stats for 'make -j':
+ Performance counter stats for 'make':

- 8117.370256 task clock ticks # 11.281 CPU utilization factor
- 678 context switches # 0.000 M/sec
- 133 CPU migrations # 0.000 M/sec
- 235724 pagefaults # 0.029 M/sec
- 24821162526 CPU cycles # 3057.784 M/sec
- 18687303457 instructions # 2302.138 M/sec
- 172158895 cache references # 21.209 M/sec
- 27075259 cache misses # 3.335 M/sec
+ 83723.452481 task-clock:u (msec) # 1.004 CPUs utilized
+ 0 context-switches:u # 0.000 K/sec
+ 0 cpu-migrations:u # 0.000 K/sec
+ 3,228,188 page-faults:u # 0.039 M/sec
+ 229,570,665,834 cycles:u # 2.742 GHz
+ 313,163,853,778 instructions:u # 1.36 insn per cycle
+ 69,704,684,856 branches:u # 832.559 M/sec
+ 2,078,861,393 branch-misses:u # 2.98% of all branches

- Wall-clock time elapsed: 719.554352 msecs
+ 83.409183620 seconds time elapsed
+
+ 74.684747000 seconds user
+ 8.739217000 seconds sys
+
+TIMINGS
+-------
+As displayed in the example above we can display 3 types of timings.
+We always display the time the counters were enabled/alive:
+
+ 83.409183620 seconds time elapsed
+
+For workload sessions we also display time the workloads spent in
+user/system lands:
+
+ 74.684747000 seconds user
+ 8.739217000 seconds sys
+
+Those times are the very same as displayed by the 'time' tool.

CSV FORMAT
----------
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index a4f662a462c6..096ccb25c11f 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"

@@ -175,6 +178,8 @@ static int output_fd;
static int print_free_counters_hint;
static int print_mixed_hw_group_error;
static u64 *walltime_run;
+static bool ru_display = false;
+static struct rusage ru_data;

struct perf_stat {
bool record;
@@ -726,7 +731,7 @@ 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));
@@ -1804,6 +1809,11 @@ 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;
@@ -1815,6 +1825,15 @@ static void print_footer(void)

if (run_count == 1) {
fprintf(output, " %17.9f seconds time elapsed", avg);
+
+ if (ru_display) {
+ double ru_utime = timeval2double(&ru_data.ru_utime);
+ double ru_stime = timeval2double(&ru_data.ru_stime);
+
+ fprintf(output, "\n\n");
+ fprintf(output, " %17.9f seconds user\n", ru_utime);
+ fprintf(output, " %17.9f seconds sys\n", ru_stime);
+ }
} else {
double sd = stddev_stats(&walltime_nsecs_stats) / NSEC_PER_SEC;
/*
@@ -2950,6 +2969,13 @@ int cmd_stat(int argc, const char **argv)

setup_system_wide(argc);

+ /*
+ * 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 (run_count < 0) {
pr_err("Run count must be a positive number\n");
parse_options_usage(stat_usage, stat_options, "r", 1);
--
2.14.3