Profiler only works with absolute URLs and paths

doc/development/profiling.md

@@ -10,6 +10,10 @@ There is a `Gitlab::Profiler.profile` method, and corresponding
 `bin/profile-url` script, that enable profiling a GET or POST request to a
 specific URL, either as an anonymous user (the default) or as a specific user.
 
+NOTE: **Note:** The first argument to the profiler is either a full URL
+(including the instance hostname) or an absolute path, including the
+leading slash.
+
 When using the script, command-line documentation is available by passing no
 arguments.