diff options
author | Jin Yao <yao.jin@linux.intel.com> | 2020-05-20 12:27:33 +0800 |
---|---|---|
committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2020-05-28 10:03:27 -0300 |
commit | 72f02a947e89223b1b4a7825b68b2ba8fd2852c8 (patch) | |
tree | 424a0de774511c9946f905b851cdadec53e73be6 | |
parent | a45badc7392b4613708748f6a2cc0c6f63a1c8d6 (diff) |
perf stat: Fix wrong per-thread runtime stat for interval mode
root@kbl-ppc:~# perf stat --per-thread -e cycles,instructions -I1000 --interval-count 2
1.004171683 perf-3696 8,747,311 cycles
...
1.004171683 perf-3696 691,730 instructions # 0.08 insn per cycle
...
2.006490373 perf-3696 1,749,936 cycles
...
2.006490373 perf-3696 1,484,582 instructions # 0.28 insn per cycle
...
Let's see interval 2.006490373
perf-3696 1,749,936 cycles
perf-3696 1,484,582 instructions # 0.28 insn per cycle
insn per cycle = 1,484,582 / 1,749,936 = 0.85.
But now it's 0.28, that's not correct.
stat_config.stats[] records the per-thread runtime stat. But for
interval mode, it should be reset for each interval.
So now, with this patch,
root@kbl-ppc:~# perf stat --per-thread -e cycles,instructions -I1000 --interval-count 2
1.005818121 perf-8633 9,898,045 cycles
...
1.005818121 perf-8633 693,298 instructions # 0.07 insn per cycle
...
2.007863743 perf-8633 1,551,619 cycles
...
2.007863743 perf-8633 1,317,514 instructions # 0.85 insn per cycle
...
Let's check interval 2.007863743.
insn per cycle = 1,317,514 / 1,551,619 = 0.85. It's correct.
This patch creates runtime_stat_reset, places it next to
untime_stat_new/runtime_stat_delete and moves all runtime_stat
functions before process_interval.
Committer testing:
After the patch:
# perf stat --per-thread -e cycles,instructions -I1000 --interval-count 2 |& grep sssd_nss-1130
2.011309774 sssd_nss-1130 56,585 cycles
2.011309774 sssd_nss-1130 13,121 instructions # 0.23 insn per cycle
# python
>>> 13121.0 / 56585
0.23188124061146947
>>>
Fixes: commit 14e72a21c783 ("perf stat: Update or print per-thread stats")
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200520042737.24160-2-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
-rw-r--r-- | tools/perf/builtin-stat.c | 70 |
1 files changed, 41 insertions, 29 deletions
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 4deb2d46a343..b03f06b541f9 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -351,6 +351,46 @@ static void read_counters(struct timespec *rs) } } +static int runtime_stat_new(struct perf_stat_config *config, int nthreads) +{ + int i; + + config->stats = calloc(nthreads, sizeof(struct runtime_stat)); + if (!config->stats) + return -1; + + config->stats_num = nthreads; + + for (i = 0; i < nthreads; i++) + runtime_stat__init(&config->stats[i]); + + return 0; +} + +static void runtime_stat_delete(struct perf_stat_config *config) +{ + int i; + + if (!config->stats) + return; + + for (i = 0; i < config->stats_num; i++) + runtime_stat__exit(&config->stats[i]); + + zfree(&config->stats); +} + +static void runtime_stat_reset(struct perf_stat_config *config) +{ + int i; + + if (!config->stats) + return; + + for (i = 0; i < config->stats_num; i++) + perf_stat__reset_shadow_per_stat(&config->stats[i]); +} + static void process_interval(void) { struct timespec ts, rs; @@ -359,6 +399,7 @@ static void process_interval(void) diff_timespec(&rs, &ts, &ref_time); perf_stat__reset_shadow_per_stat(&rt_stat); + runtime_stat_reset(&stat_config); read_counters(&rs); if (STAT_RECORD) { @@ -1737,35 +1778,6 @@ int process_cpu_map_event(struct perf_session *session, return set_maps(st); } -static int runtime_stat_new(struct perf_stat_config *config, int nthreads) -{ - int i; - - config->stats = calloc(nthreads, sizeof(struct runtime_stat)); - if (!config->stats) - return -1; - - config->stats_num = nthreads; - - for (i = 0; i < nthreads; i++) - runtime_stat__init(&config->stats[i]); - - return 0; -} - -static void runtime_stat_delete(struct perf_stat_config *config) -{ - int i; - - if (!config->stats) - return; - - for (i = 0; i < config->stats_num; i++) - runtime_stat__exit(&config->stats[i]); - - zfree(&config->stats); -} - static const char * const stat_report_usage[] = { "perf stat report [<options>]", NULL, |