diff --git a/docs/html/tools/help/hprof-conv.jd b/docs/html/tools/help/hprof-conv.jd
index f96def205fb12..982f3379e4685 100644
--- a/docs/html/tools/help/hprof-conv.jd
+++ b/docs/html/tools/help/hprof-conv.jd
@@ -8,9 +8,13 @@ The <code>hprof-conv</code> tool converts the HPROF file that is
 generated by the Android SDK tools to a standard format so you
 can view the file in a profiling tool of your choice. </p>
 
-<pre> hprof-conv &lt;infile&gt; &lt;outfile&gt;</pre>
+<pre> hprof-conv [-z] &lt;infile&gt; &lt;outfile&gt;</pre>
 
 <p>
 You can use "-" for <code>&lt;infile&gt;</code> or <code>&lt;outfile&gt;</code>
 to specify stdin or stdout.
 </p>
+
+<p>
+You can use "-z" to filter out zygote allocations shared by all applications.
+</p>