synclink_gt fix module reference

[linux-2.6-omap-h63xx.git] / Documentation / hrtimer / timer_stats.txt

diff --git a/Documentation/hrtimer/timer_stats.txt b/Documentation/hrtimer/timer_stats.txt
index 27f782e3593f2f86047fbc2e74e387710f3a0f9a..20d368c59814206d82dfa2236bdf6764fd5bee85 100644 (file)
--- a/Documentation/hrtimer/timer_stats.txt
+++ b/Documentation/hrtimer/timer_stats.txt
@@ -2,9 +2,10 @@ timer_stats - timer usage statistics
 ------------------------------------
 
 timer_stats is a debugging facility to make the timer (ab)usage in a Linux
-system visible to kernel and userspace developers. It is not intended for
-production usage as it adds significant overhead to the (hr)timer code and the
-(hr)timer data structures.
+system visible to kernel and userspace developers. If enabled in the config
+but not used it has almost zero runtime overhead, and a relatively small
+data structure overhead. Even if collection is enabled runtime all the
+locking is per-CPU and lookup is hashed.
 
 timer_stats should be used by kernel and userspace developers to verify that
 their code does not make unduly use of timers. This helps to avoid unnecessary
@@ -66,3 +67,7 @@ executed on expiry.
 
     Thomas, Ingo
 
+Added flag to indicate 'deferrable timer' in /proc/timer_stats. A deferrable
+timer will appear as follows
+  10D,     1 swapper          queue_delayed_work_on (delayed_work_timer_fn)
+