perf: Add sysfs entry to adjust multiplexing interval per PMU

This patch adds /sys/device/xxx/perf_event_mux_interval_ms to ajust
the multiplexing interval per PMU. The unit is milliseconds. Value has
to be >= 1.

In the 4th version, we renamed the sysfs file to be more consistent
with the other /proc/sys/kernel entries for perf_events.

In the 5th version, we handle the reprogramming of the hrtimer using
hrtimer_forward_now(). That way, we sync up to new timer value quickly
(suggested by Jiri Olsa).

Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/r/1364991694-5876-3-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 72138d75a60a..6fddac1b27cb 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -194,6 +194,7 @@ struct pmu {
         int * __percpu                  pmu_disable_count;
         struct perf_cpu_context * __percpu pmu_cpu_context;
         int                             task_ctx_nr;
+        int                             hrtimer_interval_ms;
 
         /*
          * Fully disable/enable this PMU, can be used to protect from the PMI