diff --git a/src/racket/src/jit.c b/src/racket/src/jit.c
index 5da28e65a9..de92d895b6 100644
--- a/src/racket/src/jit.c
+++ b/src/racket/src/jit.c
@@ -13577,7 +13577,7 @@ typedef void *(*Get_Stack_Proc)();
 # define RETURN_ADDRESS_OFFSET 1
 #endif
 
-#define CACHE_STACK_MIN_TRIGGER 1024
+#define CACHE_STACK_MIN_TRIGGER 128
 
 #define USE_STACK_CHECK 0
 
diff --git a/src/racket/src/schmach.h b/src/racket/src/schmach.h
index d66b24431b..1e058a85bb 100644
--- a/src/racket/src/schmach.h
+++ b/src/racket/src/schmach.h
@@ -39,10 +39,10 @@
 
 #ifdef STACK_GROWS_UP
 # define STK_COMP(a,b) ((a) > (b))
-# define STK_DIFF(a, b) ((a) - (b))
+# define STK_DIFF(a, b) ((b) - (a))
 #else
 # define STK_COMP(a,b) ((a) < (b))
-# define STK_DIFF(a, b) ((b) - (a))
+# define STK_DIFF(a, b) ((a) - (b))
 #endif
 
 #ifdef SHORT_ALIGN