Add support for specific clock sources

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/README b/README
index d5235de..e64853e 100644
--- a/README
+++ b/README
@@ -127,6 +127,8 @@
 	diskutil	Dump info related to disk utilization updates
 	job:x		Dump info only related to job number x
 	mutex		Dump info only related to mutex up/down ops
+	profile		Dump info related to profile extensions
+	time		Dump info related to internal time keeping
 	? or help	Show available debug options.
 
 You can specify as many as you want, eg --debug=file,mem will enable