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Date: Wed, 29 Apr 2015 09:42:38 +0200
From: Jiri Olsa <jolsa@...hat.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>,
Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
LKML <linux-kernel@...r.kernel.org>,
David Ahern <dsahern@...il.com>,
Stephane Eranian <eranian@...gle.com>,
Andi Kleen <andi@...stfloor.org>,
Minchan Kim <minchan@...nel.org>
Subject: Re: [RFC/PATCH] perf stat: Show sample events stat for a data file
On Wed, Apr 29, 2015 at 04:27:45PM +0900, Namhyung Kim wrote:
> Add --input option to 'perf stat' so that it can show event stats of the
> file. I would like to use a short '-i' option to be compatible with
> other commands but it was already taken by '--no-inherit' option, so it
> only supports the long option.
>
> The example output looks like below:
>
> $ perf record -a sleep 1
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.635 MB perf.data (1946 samples) ]
>
> $ perf stat --input perf.data
nice, but maybe I'd see this under 'perf data' command, like:
$ perf data --stat
'perf stat' does not deal with sampling.. I think that 'perf data'
is for perf.data related stuff like:
perf data convert ...
perf data ls
perf data --features
perf data --stat
...
thoughts? ;-)
jirka
>
> Total event stats for 'perf.data' file:
>
> TOTAL events: 6837
> MMAP events: 116
> COMM events: 375
> EXIT events: 2
> THROTTLE events: 12
> UNTHROTTLE events: 11
> FORK events: 374
> SAMPLE events: 1946
> MMAP2 events: 3999
> FINISHED_ROUND events: 2
>
> Sample event stats:
>
> 361,255,234 cycles
> 1,946 samples # sampling ratio 12.162% (486/4000)
>
> 0.998581085 second time sampled
>
> The sampling ratio was useful for me to determine how often the event
> was sampled - in this case the cpu cycles event was only sampled at 12%
> of the expected sampling frequency, so the system was mostly idle in
> terms of cpu cycles (or the event was multiplexed in case of recording
> large number of events at once).
>
> The sampling ratio was calulated like below:
>
> expected_freq = evsel->attr.sample_freq
> actual_freq = (nr_samples / nr_cpus) / sample_time
> sampling_ratio = 100 * actual_freq / expected_freq
>
> Cc: Minchan Kim <minchan@...nel.org>
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> ---
> tools/perf/builtin-stat.c | 91 +++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 89 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index fd577f725d23..78ded82df4a9 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -58,6 +58,7 @@
> #include "util/cpumap.h"
> #include "util/thread.h"
> #include "util/thread_map.h"
> +#include "util/hist.h"
>
> #include <stdlib.h>
> #include <sys/prctl.h>
> @@ -1576,6 +1577,87 @@ static int perf_stat_init_aggr_mode(void)
> return 0;
> }
>
> +static u64 first_sample_nsec;
> +static u64 last_sample_nsec;
> +
> +static int process_sample_event(struct perf_tool *tool __maybe_unused,
> + union perf_event *event __maybe_unused,
> + struct perf_sample *sample,
> + struct perf_evsel *evsel,
> + struct machine *machine __maybe_unused)
> +{
> + struct hists *hists = evsel__hists(evsel);
> +
> + if (!first_sample_nsec)
> + first_sample_nsec = sample->time;
> + last_sample_nsec = sample->time;
> +
> + hists->stats.total_period += sample->period;
> + hists->stats.nr_events[PERF_RECORD_SAMPLE]++;
> + return 0;
> +}
> +
> +static int show_sample_stat(void)
> +{
> + struct perf_data_file file = {
> + .mode = PERF_DATA_MODE_READ,
> + .path = input_name,
> + };
> + struct perf_tool tool = {
> + .sample = process_sample_event,
> + };
> + struct perf_session *session;
> + struct perf_evsel *evsel;
> + u64 sample_nsec;
> + int nr_cpus;
> + int ret;
> +
> + session = perf_session__new(&file, false, &tool);
> + if (session == NULL)
> + return -1;
> +
> + ret = perf_session__process_events(session);
> + if (ret < 0)
> + return ret;
> +
> + nr_cpus = session->header.env.nr_cpus_online;
> + sample_nsec = last_sample_nsec - first_sample_nsec;
> +
> + fprintf(output, "\n Total event stats for '%s' file:\n\n", input_name);
> + events_stats__fprintf(&session->evlist->stats, output);
> +
> + fprintf(output, "\n Sample event stats:\n\n");
> + evlist__for_each(session->evlist, evsel) {
> + struct hists *hists = evsel__hists(evsel);
> + struct events_stats *stats = &hists->stats;
> + u64 total_period = stats->total_period;
> + u32 nr_samples = stats->nr_events[PERF_RECORD_SAMPLE];
> +
> + fprintf(output, "%'18"PRIu64" ", total_period);
> + fprintf(output, "%-25s", perf_evsel__name(evsel));
> + fprintf(output, "\n");
> + fprintf(output, "%'18u ", nr_samples);
> + fprintf(output, "%-25s", "samples");
> +
> + if (sample_nsec && evsel->attr.freq && evsel->attr.sample_freq) {
> + int expected_rate = evsel->attr.sample_freq;
> + double sample_rate = 1.0 * nr_samples / nr_cpus;
> +
> + sample_rate *= (double)NSEC_PER_SEC / sample_nsec;
> + fprintf(output, " # sampling ratio %.3f%% (%d/%d)",
> + 100 * sample_rate / expected_rate,
> + (int)sample_rate, expected_rate);
> + }
> + fprintf(output, "\n\n");
> + }
> +
> + fprintf(output, "%18.9f second time sampled\n",
> + (double)sample_nsec / NSEC_PER_SEC);
> +
> + perf_session__delete(session);
> + return 0;
> +}
> +
> static int setup_events(const char * const *attrs, unsigned len)
> {
> unsigned i;
> @@ -1793,6 +1875,7 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
> "print counts with custom separator"),
> OPT_CALLBACK('G', "cgroup", &evsel_list, "name",
> "monitor event in cgroup name only", parse_cgroups),
> + OPT_STRING(0, "input", &input_name, "file", "input file name"),
> OPT_STRING('o', "output", &output_name, "file", "output file name"),
> OPT_BOOLEAN(0, "append", &append_file, "append to the output file"),
> OPT_INTEGER(0, "log-fd", &output_fd,
> @@ -1886,8 +1969,12 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
> } else if (big_num_opt == 0) /* User passed --no-big-num */
> big_num = false;
>
> - if (!argc && target__none(&target))
> - usage_with_options(stat_usage, options);
> + if (!argc && target__none(&target)) {
> + if (!input_name)
> + usage_with_options(stat_usage, options);
> + status = show_sample_stat();
> + goto out;
> + }
>
> if (run_count < 0) {
> pr_err("Run count must be a positive number\n");
> --
> 2.3.5
>
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