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Date: Fri, 8 May 2020 09:11:49 +0800
From: "Jin, Yao" <yao.jin@...ux.intel.com>
To: Jiri Olsa <jolsa@...hat.com>
Cc: acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
mingo@...hat.com, alexander.shishkin@...ux.intel.com,
Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v3 4/4] perf stat: Report summary for interval mode
Hi Jiri,
On 5/7/2020 11:18 PM, Jiri Olsa wrote:
> On Thu, May 07, 2020 at 02:58:22PM +0800, Jin Yao wrote:
>> 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@...-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@...-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@...-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@...ux.intel.com>
>> ---
>> 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) {
>
> you'll go through all the affinity setup and do nothing at the end,
> even if you know at the begining that it's the case.. not good
>
> we need to call only the perf_stat_process_counter in summary case
>
> jirka
>
The interval processing and non-interval processing both need to call
read_counters.
I need to prevent calling read_counter_cpu in read_counters for non-interval
otherwise the summary counts will be bigger than the sum of interval counts.
e.g.
interval: read_counter_cpu
interval: read_counter_cpu
interval: read_counter_cpu
interval mode is over,
non-interval: read_counter_cpu /* prevent this time read_counter_cpu */
Since read_counter_cpu is called before perf_stat_process_counter, so I can't do
this in perf_stat_process_counter.
Yes, it's not good to check stat_config.summary in loops, low efficiency.
Maybe we can move the codes of affinity setup and read_counter_cpu to a new
function, such as affinity_read_counters and change the read_counters to:
void read_counters()
{
if (!stat_config.summary)
affinity_read_counters();
evlist__for_each_entry(evsel_list, counter) {
perf_stat_process_counter(&stat_config, counter));
}
}
Thanks
Jin Yao
>> 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
>>
>
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