diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 2eedae8498d3..23ddd29730f8 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -260,6 +260,7 @@ enum perf_event_type {
 	/*
 	 * struct {
 	 * 	struct perf_event_header	header;
+	 * 	u64				time;
 	 * 	u64				irq_period;
 	 * };
 	 */
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index c10055416dea..2f410ea2cb39 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -2559,7 +2559,8 @@ void perf_counter_munmap(unsigned long addr, unsigned long len,
 }
 
 /*
- *
+ * Log irq_period changes so that analyzing tools can re-normalize the
+ * event flow.
  */
 
 static void perf_log_period(struct perf_counter *counter, u64 period)
diff --git a/kernel/sched.c b/kernel/sched.c
index 4c0d58bce6b2..ad079f07c9c8 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4875,9 +4875,10 @@ void scheduler_tick(void)
 	update_rq_clock(rq);
 	update_cpu_load(rq);
 	curr->sched_class->task_tick(rq, curr, 0);
-	perf_counter_task_tick(curr, cpu);
 	spin_unlock(&rq->lock);
 
+	perf_counter_task_tick(curr, cpu);
+
 #ifdef CONFIG_SMP
 	rq->idle_at_tick = idle_cpu(cpu);
 	trigger_load_balance(rq, cpu);