1 files changed, 7 insertions, 0 deletions
diff --git a/NOTES.txt b/NOTES.txt
index 0759acf355..6fc312c0c3 100644
--- a/NOTES.txt
+++ b/NOTES.txt
@@ -11,6 +11,13 @@ To time GCC preprocessing speed without output, use:
    "time gcc -MM file"
 This is similar to -Eonly.
 
+//===---------------------------------------------------------------------===//
+
+Creating and using a PTH file for performance measurement (use a release-asserts
+build).
+
+$ clang -x objective-c-header INPUTS/Cocoa_h.m -o /tmp/tokencache
+$ clang -token-cache /tmp/tokencache INPUTS/Cocoa_h.m
 
 //===---------------------------------------------------------------------===//