Commit 00093b31 authored Jan 19, 2026 by Swapnil Sapkal Committed by Arnaldo Carvalho de Melo Jan 22, 2026

perf sched stats: Add support for live mode



The live mode works similar to simple `perf stat` command, by profiling
the target and printing results on the terminal as soon as the target
finishes.

Example usage:

  # perf sched stats -- true
  Description
  ----------------------------------------------------------------------------------------------------
  DESC                          -> Description of the field
  COUNT                         -> Value of the field
  PCT_CHANGE                    -> Percent change with corresponding base value
  AVG_JIFFIES                   -> Avg time in jiffies between two consecutive occurrence of event
  ----------------------------------------------------------------------------------------------------

  Time elapsed (in jiffies)                                        :           1
  ----------------------------------------------------------------------------------------------------
  CPU: <ALL CPUS SUMMARY>
  ----------------------------------------------------------------------------------------------------
  DESC                                                                     COUNT   PCT_CHANGE
  ----------------------------------------------------------------------------------------------------
  yld_count                                                        :           0
  array_exp                                                        :           0
  sched_count                                                      :           0
  sched_goidle                                                     :           0  (     0.00% )
  ttwu_count                                                       :           0
  ttwu_local                                                       :           0  (     0.00% )
  rq_cpu_time                                                      :       27875
  run_delay                                                        :           0  (     0.00% )
  pcount                                                           :           0
  ----------------------------------------------------------------------------------------------------
  CPU: <ALL CPUS SUMMARY> | DOMAIN: SMT
  ----------------------------------------------------------------------------------------------------
  DESC                                                                     COUNT    AVG_JIFFIES
  ----------------------------------------- <Category busy> ------------------------------------------
  busy_lb_count                                                    :           0  $        0.00 $
  busy_lb_balanced                                                 :           0  $        0.00 $
  busy_lb_failed                                                   :           0  $        0.00 $
  busy_lb_imbalance_load                                           :           0
  busy_lb_imbalance_util                                           :           0
  busy_lb_imbalance_task                                           :           0
  busy_lb_imbalance_misfit                                         :           0
  busy_lb_gained                                                   :           0
  busy_lb_hot_gained                                               :           0
  busy_lb_nobusyq                                                  :           0  $        0.00 $
  busy_lb_nobusyg                                                  :           0  $        0.00 $
  *busy_lb_success_count                                           :           0
  *busy_lb_avg_pulled                                              :        0.00

  ... and so on. Output will show similar data for all the cpus in the
system.

Co-developed-by: Ravi Bangoria <ravi.bangoria@amd.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Signed-off-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Tested-by: James Clark <james.clark@linaro.org>
Acked-by: Ian Rogers <irogers@google.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Anubhav Shelat <ashelat@redhat.com>
Cc: Ben Gainey <ben.gainey@arm.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Chun-Tse Shao <ctshao@google.com>
Cc: David Vernet <void@manifault.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Dr. David Alan Gilbert <linux@treblig.org>
Cc: Gautham Shenoy <gautham.shenoy@amd.com>
Cc: Graham Woodward <graham.woodward@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Madadi Vineeth Reddy <vineethr@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Santosh Shukla <santosh.shukla@amd.com>
Cc: Shrikanth Hegde <sshegde@linux.ibm.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Falcon <thomas.falcon@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Yang Jihong <yangjihong@bytedance.com>
Cc: Yujie Liu <yujie.liu@intel.com>
Cc: Zhongqiu Han <quic_zhonhan@quicinc.com>
[ Avoid potentially using 'sv' uninitialized by calling free_cpu_domain_info() only when build_cpu_domain_map() is called ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 5a357ae6

tools/perf/builtin-sched.c

+98 −1

Original line number	Diff line number	Diff line
		@@ -4426,6 +4426,103 @@ static int perf_sched__schedstat_report(struct perf_sched *sched)
		return err;
		}

		static int process_synthesized_event_live(const struct perf_tool *tool __maybe_unused,
		union perf_event *event,
		struct perf_sample *sample __maybe_unused,
		struct machine *machine __maybe_unused)
		{
		return perf_sched__process_schedstat(tool, NULL, event);
		}

		static int perf_sched__schedstat_live(struct perf_sched *sched,
		int argc, const char **argv)
		{
		struct cpu_domain_map **cd_map = NULL;
		struct target target = {};
		u32 __maybe_unused md;
		struct evlist *evlist;
		u32 nr = 0, sv;
		int reset = 0;
		int err = 0;

		signal(SIGINT, sighandler);
		signal(SIGCHLD, sighandler);
		signal(SIGTERM, sighandler);

		evlist = evlist__new();
		if (!evlist)
		return -ENOMEM;

		/*
		* `perf sched schedstat` does not support workload profiling (-p pid)
		* since /proc/schedstat file contains cpu specific data only. Hence, a
		* profile target is either set of cpus or systemwide, never a process.
		* Note that, although `-- <workload>` is supported, profile data are
		* still cpu/systemwide.
		*/
		if (cpu_list)
		target.cpu_list = cpu_list;
		else
		target.system_wide = true;

		if (argc) {
		err = evlist__prepare_workload(evlist, &target, argv, false, NULL);
		if (err)
		goto out;
		}

		err = evlist__create_maps(evlist, &target);
		if (err < 0)
		goto out;

		user_requested_cpus = evlist->core.user_requested_cpus;

		err = perf_event__synthesize_schedstat(&(sched->tool),
		process_synthesized_event_live,
		user_requested_cpus);
		if (err < 0)
		goto out;

		err = enable_sched_schedstats(&reset);
		if (err < 0)
		goto out;

		if (argc)
		evlist__start_workload(evlist);

		/* wait for signal */
		pause();

		if (reset) {
		err = disable_sched_schedstat();
		if (err < 0)
		goto out;
		}

		err = perf_event__synthesize_schedstat(&(sched->tool),
		process_synthesized_event_live,
		user_requested_cpus);
		if (err)
		goto out;

		setup_pager();

		if (list_empty(&cpu_head)) {
		pr_err("Data is not available\n");
		err = -1;
		goto out;
		}

		nr = cpu__max_present_cpu().cpu;
		cd_map = build_cpu_domain_map(&sv, &md, nr);
		show_schedstat_data(&cpu_head, cd_map);
		free_cpu_domain_info(cd_map, sv, nr);
		out:
		free_schedstat(&cpu_head);
		evlist__delete(evlist);
		return err;
		}

		static bool schedstat_events_exposed(void)
		{
		/*
		@@ -4751,7 +4848,7 @@ int cmd_sched(int argc, const char **argv)
		stats_usage, 0);
		return perf_sched__schedstat_report(&sched);
		}
		usage_with_options(stats_usage, stats_options);
		return perf_sched__schedstat_live(&sched, argc, argv);
		} else {
		usage_with_options(sched_usage, sched_options);
		}

tools/perf/util/header.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -1614,8 +1614,7 @@ static int write_pmu_caps(struct feat_fd *ff,
		return 0;
		}

		static struct cpu_domain_map *build_cpu_domain_map(u32 schedstat_version, u32 *max_sched_domains,
		u32 nr)
		struct cpu_domain_map *build_cpu_domain_map(u32 schedstat_version, u32 *max_sched_domains, u32 nr)
		{
		struct domain_info *domain_info;
		struct cpu_domain_map **cd_map;

tools/perf/util/header.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -211,4 +211,7 @@ char *get_cpuid_str(struct perf_cpu cpu);
		char *get_cpuid_allow_env_override(struct perf_cpu cpu);

		int strcmp_cpuid_str(const char s1, const char s2);

		struct cpu_domain_map *build_cpu_domain_map(u32 schedstat_version, u32 *max_sched_domains,
		u32 nr);
		#endif /* __PERF_HEADER_H */