From f1f8ad52f8bf1239282737a2a5c3bd450300cc78 Mon Sep 17 00:00:00 2001 From: yuzhoujian Date: Mon, 29 Jan 2018 10:25:23 +0100 Subject: [PATCH] perf stat: Add support to print counts after a period of time Introduce a new option to print counts after N milliseconds and update 'perf stat' documentation accordingly. Show below is the output of the new option for perf stat. $ perf stat --time 2000 -e cycles -a Performance counter stats for 'system wide': 157,260,423 cycles 2.003060766 seconds time elapsed We can print the count deltas after N milliseconds with this new introduced option. This option is not supported with "-I" option. In addition, according to Kangliang's patch(19afd10410957), the monitoring overhead for system-wide core event could be very high if the interval-print parameter was below 100ms, and the limitation value is 10ms. So the same warning will be displayed when the time is set between 10ms to 100ms, and the minimal time is limited to 10ms. Users can make a decision according to their spcific cases. Committer notes: This actually stops the workload after the specified time, then prints the counts. So I renamed the option to --timeout and updated the documentation to state that it will not just print the counts after the specified time, but will really stop the 'perf stat' session and print the counts. The rename from 'time' to 'timeout' also fixes the build in systems where 'time' is used by glibc and can't be used as a name of a variable, such as centos:5 and centos:6. Changes since v3: - none. Changes since v2: - modify the time check in __run_perf_stat func to keep some consistency with the workload case. - add the warning when the time is set between 10ms to 100ms. - add the pr_err when the time is set below 10ms. Changes since v1: - none. Signed-off-by: yuzhoujian Acked-by: Jiri Olsa Cc: Adrian Hunter Cc: Alexander Shishkin Cc: David Ahern Cc: Kan Liang Cc: Milian Wolff Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Wang Nan Link: http://lkml.kernel.org/r/1517217923-8302-3-git-send-email-ufo19890607@gmail.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/Documentation/perf-stat.txt | 5 ++++ tools/perf/builtin-stat.c | 33 ++++++++++++++++++++++++-- tools/perf/util/stat.h | 1 + 3 files changed, 37 insertions(+), 2 deletions(-) diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt index 47a21645f60c..2bbe79a50d3c 100644 --- a/tools/perf/Documentation/perf-stat.txt +++ b/tools/perf/Documentation/perf-stat.txt @@ -151,6 +151,11 @@ 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' +--timeout msecs:: +Stop the 'perf stat' session and print count deltas after N milliseconds (minimum: 10 ms). +This option is not supported with the "-I" option. + example: 'perf stat --time 2000 -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 7d1d7613bf56..2d49eccf98f2 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -573,6 +573,7 @@ static int __run_perf_stat(int argc, const char **argv) { int interval = stat_config.interval; int times = stat_config.times; + int timeout = stat_config.timeout; char msg[BUFSIZ]; unsigned long long t0, t1; struct perf_evsel *counter; @@ -586,6 +587,9 @@ static int __run_perf_stat(int argc, const char **argv) if (interval) { ts.tv_sec = interval / USEC_PER_MSEC; ts.tv_nsec = (interval % USEC_PER_MSEC) * NSEC_PER_MSEC; + } else if (timeout) { + ts.tv_sec = timeout / USEC_PER_MSEC; + ts.tv_nsec = (timeout % USEC_PER_MSEC) * NSEC_PER_MSEC; } else { ts.tv_sec = 1; ts.tv_nsec = 0; @@ -698,9 +702,11 @@ try_again: perf_evlist__start_workload(evsel_list); enable_counters(); - if (interval) { + if (interval || timeout) { while (!waitpid(child_pid, &status, WNOHANG)) { nanosleep(&ts, NULL); + if (timeout) + break; process_interval(); if (interval_count && !(--times)) break; @@ -720,6 +726,8 @@ try_again: enable_counters(); while (!done) { nanosleep(&ts, NULL); + if (timeout) + break; if (interval) { process_interval(); if (interval_count && !(--times)) @@ -1900,6 +1908,8 @@ static const struct option stat_options[] = { "print counts at regular interval in ms (>= 10)"), OPT_INTEGER(0, "interval-count", &stat_config.times, "print counts for fixed number of times"), + OPT_UINTEGER(0, "timeout", &stat_config.timeout, + "stop workload and print counts after a timeout period in ms (>= 10ms)"), 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, @@ -2697,7 +2707,7 @@ int cmd_stat(int argc, const char **argv) int status = -EINVAL, run_idx; const char *mode; FILE *output = stderr; - unsigned int interval; + unsigned int interval, timeout; const char * const stat_subcommands[] = { "record", "report" }; setlocale(LC_ALL, ""); @@ -2728,6 +2738,7 @@ int cmd_stat(int argc, const char **argv) return __cmd_report(argc, argv); interval = stat_config.interval; + timeout = stat_config.timeout; /* * For record command the -o is already taken care of. @@ -2879,6 +2890,7 @@ 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) { @@ -2889,6 +2901,23 @@ int cmd_stat(int argc, const char **argv) goto out; } + if (timeout && timeout < 100) { + if (timeout < 10) { + pr_err("timeout must be >= 10ms.\n"); + parse_options_usage(stat_usage, stat_options, "timeout", 0); + goto out; + } else + pr_warning("timeout < 100ms. " + "The overhead percentage could be high in some cases. " + "Please proceed with caution.\n"); + } + if (timeout && interval) { + pr_err("timeout option is not supported with interval-print.\n"); + parse_options_usage(stat_usage, stat_options, "timeout", 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 540fbb350e53..2f44e386a0e8 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; + unsigned int timeout; int times; struct runtime_stat *stats; int stats_num;