perf: Fix event scaling for inherited counters

Properly account the full hierarchy of counters for both the
count (we already did so) and the scale times (new).

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091120212509.153379276@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 28 insertions, 23 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index a430ac3074af..36fe89f72641 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -782,7 +782,8 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr,
 				int cpu,
 				pid_t pid,
 				perf_callback_t callback);
-extern u64 perf_event_read_value(struct perf_event *event);
+extern u64 perf_event_read_value(struct perf_event *event,
+				 u64 *enabled, u64 *running);
 
 struct perf_sample_data {
 	u64				type;
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index fdfae888a67c..80f40da9a01e 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -1774,14 +1774,25 @@ static int perf_event_read_size(struct perf_event *event)
 	return size;
 }
 
-u64 perf_event_read_value(struct perf_event *event)
+u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
 {
 	struct perf_event *child;
 	u64 total = 0;
 
+	*enabled = 0;
+	*running = 0;
+
 	total += perf_event_read(event);
-	list_for_each_entry(child, &event->child_list, child_list)
+	*enabled += event->total_time_enabled +
+			atomic64_read(&event->child_total_time_enabled);
+	*running += event->total_time_running +
+			atomic64_read(&event->child_total_time_running);
+
+	list_for_each_entry(child, &event->child_list, child_list) {
 		total += perf_event_read(child);
+		*enabled += child->total_time_enabled;
+		*running += child->total_time_running;
+	}
 
 	return total;
 }
@@ -1793,19 +1804,15 @@ static int perf_event_read_group(struct perf_event *event,
 	struct perf_event *leader = event->group_leader, *sub;
 	int n = 0, size = 0, ret = 0;
 	u64 values[5];
-	u64 count;
+	u64 count, enabled, running;
 
-	count = perf_event_read_value(leader);
+	count = perf_event_read_value(leader, &enabled, &running);
 
 	values[n++] = 1 + leader->nr_siblings;
-	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
-		values[n++] = leader->total_time_enabled +
-			atomic64_read(&leader->child_total_time_enabled);
-	}
-	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
-		values[n++] = leader->total_time_running +
-			atomic64_read(&leader->child_total_time_running);
-	}
+	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+		values[n++] = enabled;
+	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+		values[n++] = running;
 	values[n++] = count;
 	if (read_format & PERF_FORMAT_ID)
 		values[n++] = primary_event_id(leader);
@@ -1820,7 +1827,7 @@ static int perf_event_read_group(struct perf_event *event,
 	list_for_each_entry(sub, &leader->sibling_list, group_entry) {
 		n = 0;
 
-		values[n++] = perf_event_read_value(sub);
+		values[n++] = perf_event_read_value(sub, &enabled, &running);
 		if (read_format & PERF_FORMAT_ID)
 			values[n++] = primary_event_id(sub);
 
@@ -1838,18 +1845,15 @@ static int perf_event_read_group(struct perf_event *event,
 static int perf_event_read_one(struct perf_event *event,
 				 u64 read_format, char __user *buf)
 {
+	u64 enabled, running;
 	u64 values[4];
 	int n = 0;
 
-	values[n++] = perf_event_read_value(event);
-	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
-		values[n++] = event->total_time_enabled +
-			atomic64_read(&event->child_total_time_enabled);
-	}
-	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
-		values[n++] = event->total_time_running +
-			atomic64_read(&event->child_total_time_running);
-	}
+	values[n++] = perf_event_read_value(event, &enabled, &running);
+	if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
+		values[n++] = enabled;
+	if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
+		values[n++] = running;
 	if (read_format & PERF_FORMAT_ID)
 		values[n++] = primary_event_id(event);