[PATCH v4 1/2] perf stat: Add support to print counts for fixed times

From: ufo19890607
Date: Mon Jan 29 2018 - 04:25:54 EST


From: yuzhoujian <yuzhoujian@xxxxxxxxxxxxxxx>

Introduce a new option to print counts for fixed number of times
and update perf-stat documentation accordingly.

Show below is the output of the new option for perf stat.

$ perf stat -I 1000 --interval-count 2 -e cycles -a
# time counts unit events
1.002827089 93,884,870 cycles
2.004231506 56,573,446 cycles

We can just print the counts for several times with this newly introduced
option. The usage of it is a little like vmstat, and it should be used
together with "-I" option.

$ vmstat -n 1 2
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
0 0 0 78270544 547484 51732076 0 0 0 20 1 1 1 0 99 0 0
0 0 0 78270512 547484 51732080 0 0 0 16 477 1555 0 0 100 0 0

Changes since v3:
- merge interval_count check and times check to one line.
- fix the wrong indent in stat.h
- use stat_config.times instead of 'times' in cmd_stat function.

Changes since v2:
- none.

Changes since v1:
- change the name of the new option "times-print" to "interval-count".
- keep the new option interval specifically.

Signed-off-by: yuzhoujian <yuzhoujian@xxxxxxxxxxxxxxx>
---
tools/perf/Documentation/perf-stat.txt | 5 +++++
tools/perf/builtin-stat.c | 20 +++++++++++++++++++-
tools/perf/util/stat.h | 1 +
3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
index 823fce7674bb..47a21645f60c 100644
--- a/tools/perf/Documentation/perf-stat.txt
+++ b/tools/perf/Documentation/perf-stat.txt
@@ -146,6 +146,11 @@ Print count deltas every N milliseconds (minimum: 10ms)
The overhead percentage could be high in some cases, for instance with small, sub 100ms intervals. Use with caution.
example: 'perf stat -I 1000 -e cycles -a sleep 5'

+--interval-count times::
+Print count deltas for fixed number of times.
+This option should be used together with "-I" option.
+ example: 'perf stat -I 1000 --interval-count 2 -e cycles -a'
+
--metric-only::
Only print computed metrics. Print them in a single line.
Don't show any raw values. Not supported with --per-thread.
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 98bf9d32f222..7d1d7613bf56 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -168,6 +168,7 @@ static struct timespec ref_time;
static struct cpu_map *aggr_map;
static aggr_get_id_t aggr_get_id;
static bool append_file;
+static bool interval_count;
static const char *output_name;
static int output_fd;
static int print_free_counters_hint;
@@ -571,6 +572,7 @@ static struct perf_evsel *perf_evsel__reset_weak_group(struct perf_evsel *evsel)
static int __run_perf_stat(int argc, const char **argv)
{
int interval = stat_config.interval;
+ int times = stat_config.times;
char msg[BUFSIZ];
unsigned long long t0, t1;
struct perf_evsel *counter;
@@ -700,6 +702,8 @@ static int __run_perf_stat(int argc, const char **argv)
while (!waitpid(child_pid, &status, WNOHANG)) {
nanosleep(&ts, NULL);
process_interval();
+ if (interval_count && !(--times))
+ break;
}
}
waitpid(child_pid, &status, 0);
@@ -716,8 +720,11 @@ static int __run_perf_stat(int argc, const char **argv)
enable_counters();
while (!done) {
nanosleep(&ts, NULL);
- if (interval)
+ if (interval) {
process_interval();
+ if (interval_count && !(--times))
+ break;
+ }
}
}

@@ -1891,6 +1898,8 @@ static const struct option stat_options[] = {
"command to run after to the measured command"),
OPT_UINTEGER('I', "interval-print", &stat_config.interval,
"print counts at regular interval in ms (>= 10)"),
+ OPT_INTEGER(0, "interval-count", &stat_config.times,
+ "print counts for fixed number of times"),
OPT_SET_UINT(0, "per-socket", &stat_config.aggr_mode,
"aggregate counts per processor socket", AGGR_SOCKET),
OPT_SET_UINT(0, "per-core", &stat_config.aggr_mode,
@@ -2870,6 +2879,15 @@ int cmd_stat(int argc, const char **argv)
"The overhead percentage could be high in some cases. "
"Please proceed with caution.\n");
}
+ if (stat_config.times && interval)
+ interval_count = true;
+ else if (stat_config.times && !interval) {
+ pr_err("interval-count option should be used together with "
+ "interval-print.\n");
+ parse_options_usage(stat_usage, stat_options, "interval-count", 0);
+ parse_options_usage(stat_usage, stat_options, "I", 1);
+ goto out;
+ }

if (perf_evlist__alloc_stats(evsel_list, interval))
goto out;
diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
index dbc6f7134f61..540fbb350e53 100644
--- a/tools/perf/util/stat.h
+++ b/tools/perf/util/stat.h
@@ -90,6 +90,7 @@ struct perf_stat_config {
bool scale;
FILE *output;
unsigned int interval;
+ int times;
struct runtime_stat *stats;
int stats_num;
};
--
2.14.1