diff --git a/Documentation/lockstat.txt b/Documentation/lockstat.txt
index 4ba4664..02f36f5c 100644
--- a/Documentation/lockstat.txt
+++ b/Documentation/lockstat.txt
@@ -100,6 +100,7 @@
 short separator. The contention points don't match the column descriptors,
 they have two: contentions and [<IP>] symbol.
 
+The integer part of the time values is in us.
 
 View the top contending locks: