diff -up linux-2.6.32-22.planetlab.i686/tools/perf/Makefile.orig linux-2.6.32-22.planetlab.i686/tools/perf/Makefile
--- linux-2.6.32-22.planetlab.i686/tools/perf/Makefile.orig	2011-07-21 10:27:04.816021371 -0400
+++ linux-2.6.32-22.planetlab.i686/tools/perf/Makefile	2011-07-21 10:27:16.325140524 -0400
@@ -219,7 +219,7 @@ EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wde
 #
 
 LESS_WARNINGS := -Wno-system-headers
-LESS_WARNINGS := $(LESS_WARNINGS) -Wno-unused-but-set-variable
+LESS_WARNINGS := $(LESS_WARNINGS) #-Wno-unused-but-set-variable
 
 ifeq ("$(origin DEBUG)", "command line")
   PERF_DEBUG = $(DEBUG)