diff --git a/regressions/ck_ht/benchmark/Makefile b/regressions/ck_ht/benchmark/Makefile
index 536e08e..c02aa68 100644
--- a/regressions/ck_ht/benchmark/Makefile
+++ b/regressions/ck_ht/benchmark/Makefile
@@ -17,4 +17,4 @@ clean:
 	rm -rf *~ *.o $(OBJECTS) *.dSYM
 
 include ../../../build/regressions.build
-CFLAGS+=-D_GNU_SOURCE -DCK_MD_RDTSCP
+CFLAGS+=-D_GNU_SOURCE