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>

3 files changed, 102 insertions, 3 deletions

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index c6b054b9b12a..ec9fa29196b2 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -4426,6 +4426,103 @@ out:
 	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);
 	}
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 673d53bb2a2c..9a15dd4b7640 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -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;
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index c62f3275a80f..36cc74e2d14d 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -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 */