diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt
index e4aa268d2e38..c599623a1f3d 100644
--- a/tools/perf/Documentation/perf-config.txt
+++ b/tools/perf/Documentation/perf-config.txt
@@ -40,6 +40,10 @@ The '$HOME/.perfconfig' file is used to store a per-user configuration.
 The file '$(sysconfdir)/perfconfig' can be used to
 store a system-wide default configuration.
 
+One an disable reading config files by setting the PERF_CONFIG environment
+variable to /dev/null, or provide an alternate config file by setting that
+variable.
+
 When reading or writing, the values are read from the system and user
 configuration files by default, and options '--system' and '--user'
 can be used to tell the command to read from or write to only that location.