diff --git a/common.mk b/common.mk
index 36174c3ac4..ce7434f0fb 100644
--- a/common.mk
+++ b/common.mk
@@ -834,6 +834,7 @@ help: PHONY
 	@echo "  test-all:        all ruby tests"
 	@echo "  test-rubyspec    run RubySpec test suite"
 	@echo "  update-rubyspec  update local copy of RubySpec"
+	@echo "  benchmark        benchmark this ruby and COMPARE_RUBY"
 	@echo "  install:         install all ruby distributions"
 	@echo "  install-nodoc:   install without rdoc"
 	@echo "  clean:           clean built objects"