Re: [BUG] perf_event: when events are grouped, the time enabled /running values are incorrect

From: Peter Zijlstra
Date: Wed May 12 2010 - 13:50:54 EST


On Wed, 2010-05-12 at 10:25 -0700, Corey Ashford wrote:

> Thanks for looking into this problem! Unfortunately, I've been unable
> to test your patch. It doesn't apply to 2.6.33.3

Strange the code looks very similar, the below is a diff against a
virgin v2.6.33.3.

---
kernel/perf_event.c | 26 +++++++++++++-------------
1 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 32d0ae2..e8ae0c2 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -290,6 +290,18 @@ static void update_event_times(struct perf_event *event)
}

/*
+ * Update total_time_enabled and total_time_running for all events in a group.
+ */
+static void update_group_times(struct perf_event *leader)
+{
+ struct perf_event *event;
+
+ update_event_times(leader);
+ list_for_each_entry(event, &leader->sibling_list, group_entry)
+ update_event_times(event);
+}
+
+/*
* Add a event from the lists for its context.
* Must be called with ctx->mutex and ctx->lock held.
*/
@@ -337,7 +349,7 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx)
if (event->group_leader != event)
event->group_leader->nr_siblings--;

- update_event_times(event);
+ update_group_times(event);

/*
* If event was in error state, then keep it
@@ -508,18 +520,6 @@ retry:
}

/*
- * Update total_time_enabled and total_time_running for all events in a group.
- */
-static void update_group_times(struct perf_event *leader)
-{
- struct perf_event *event;
-
- update_event_times(leader);
- list_for_each_entry(event, &leader->sibling_list, group_entry)
- update_event_times(event);
-}
-
-/*
* Cross CPU call to disable a performance event
*/
static void __perf_event_disable(void *info)


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/