add slot randomization to configuration header

config.h

@@ -3,5 +3,6 @@
 
 #define GUARD_SLABS true
 #define WRITE_AFTER_FREE_CHECK true
+#define SLOT_RANDOMIZE true
 
 #endif

malloc.c

@@ -204,6 +204,7 @@ static size_t get_free_slot(struct random_state *rng, size_t slots, struct slab_
         fatal_error("no zero bits");
     }
 
+    if (SLOT_RANDOMIZE) {
         // randomize start location for linear search (uniform random choice is too slow)
         uint64_t random_split = ~(~0UL << get_random_u16_uniform(rng, slots));
 
@@ -211,6 +212,8 @@ static size_t get_free_slot(struct random_state *rng, size_t slots, struct slab_
         if (slot) {
             return slot - 1;
         }
+    }
+
     return ffzl(masked) - 1;
 }