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 3e003237c42f..2ce87ef5a3e6 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",