perf tools: Implement counter output multiplexing

Finish the -M/--multiplex option implementation:

 - separate it out from group_fd

 - correctly set it via the ioctl and dont mmap counters that
   are multiplexed

 - modify the perf record event loop to deal with buffer-less
   counters.

 - remove the -g option from perf sched record

 - account for unordered events in perf sched latency

 - (add -f to perf sched record to ease measurements)

 - skip idle threads (pid==0) in latency output

The result is better latency output by 'perf sched latency':

 -----------------------------------------------------------------------------------
  Task              |  Runtime ms | Switches | Average delay ms | Maximum delay ms |
 -----------------------------------------------------------------------------------
  ksoftirqd/8       |    0.071 ms |        2 | avg:    0.458 ms | max:    0.913 ms |
  at-spi-registry   |    0.609 ms |       19 | avg:    0.013 ms | max:    0.023 ms |
  perf              |    3.316 ms |       16 | avg:    0.013 ms | max:    0.054 ms |
  Xorg              |    0.392 ms |       19 | avg:    0.011 ms | max:    0.018 ms |
  sleep             |    0.537 ms |        2 | avg:    0.009 ms | max:    0.009 ms |
 -----------------------------------------------------------------------------------
  TOTAL:            |    4.925 ms |       58 |
 ---------------------------------------------

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 22 insertions, 3 deletions

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 3e003237c42..2ce87ef5a3e 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -116,6 +116,8 @@ static u64			sum_fluct;
 static u64			run_avg;
 
 static unsigned long		replay_repeat = 10;
+static unsigned long		nr_timestamps;
+static unsigned long		unordered_timestamps;
 
 #define TASK_STATE_TO_CHAR_STR "RSDTtZX"
 
@@ -1109,8 +1111,11 @@ latency_wakeup_event(struct trace_wakeup_event *wakeup_event,
 	if (atom->state != THREAD_SLEEPING)
 		return;
 
-	if (atom->sched_out_time > timestamp)
+	nr_timestamps++;
+	if (atom->sched_out_time > timestamp) {
+		unordered_timestamps++;
 		return;
+	}
 
 	atom->state = THREAD_WAIT_CPU;
 	atom->wake_up_time = timestamp;
@@ -1130,6 +1135,11 @@ static void output_lat_thread(struct task_atoms *atom_list)
 
 	if (!atom_list->nb_atoms)
 		return;
+	/*
+	 * Ignore idle threads:
+	 */
+	if (!atom_list->thread->pid)
+		return;
 
 	all_runtime += atom_list->total_runtime;
 	all_count += atom_list->nb_atoms;
@@ -1301,8 +1311,16 @@ static void __cmd_lat(void)
 	}
 
 	printf("-----------------------------------------------------------------------------------\n");
-	printf(" TOTAL:            |%9.3f ms |%9Ld |\n",
+	printf(" TOTAL:            |%9.3f ms |%9Ld |",
 		(double)all_runtime/1e6, all_count);
+
+	if (unordered_timestamps && nr_timestamps) {
+		printf(" INFO: %.2f%% unordered events.\n",
+			(double)unordered_timestamps/(double)nr_timestamps*100.0);
+	} else {
+		printf("\n");
+	}
+
 	printf("---------------------------------------------\n");
 }
 
@@ -1667,12 +1685,13 @@ static const char *record_args[] = {
 	"-a",
 	"-R",
 	"-M",
-	"-g",
+	"-f",
 	"-c", "1",
 	"-e", "sched:sched_switch:r",
 	"-e", "sched:sched_stat_wait:r",
 	"-e", "sched:sched_stat_sleep:r",
 	"-e", "sched:sched_stat_iowait:r",
+	"-e", "sched:sched_stat_runtime:r",
 	"-e", "sched:sched_process_exit:r",
 	"-e", "sched:sched_process_fork:r",
 	"-e", "sched:sched_wakeup:r",