Index: uspace/lib/c/include/perf.h
===================================================================
--- uspace/lib/c/include/perf.h	(revision 5fbc1f953112da8e25c6e6c8da0736cdea4af484)
+++ uspace/lib/c/include/perf.h	(revision 94d52d53a4608577d762072e1163d6e80af5bb39)
@@ -74,4 +74,6 @@
 /** Start the stopwatch.
  *
+ * Note that repeated starts/stops do NOT aggregate the elapsed time.
+ *
  * @param stopwatch Stopwatch to start.
  */
@@ -82,4 +84,6 @@
 
 /** Stop the stopwatch.
+ *
+ * Note that repeated starts/stops do NOT aggregate the elapsed time.
  *
  * @param stopwatch Stopwatch to stop.