diff --git a/Documentation/trace/histogram.txt b/Documentation/trace/histogram.txt
index b2145f44b190d..a4143f04a097a 100644
--- a/Documentation/trace/histogram.txt
+++ b/Documentation/trace/histogram.txt
@@ -73,6 +73,7 @@
 	.sym-offset display an address as a symbol and offset
 	.syscall    display a syscall id as a system call name
 	.execname   display a common_pid as a program name
+	.log2       display log2 value rather than raw number
 
   Note that in general the semantics of a given field aren't
   interpreted when applying a modifier to it, but there are some