diff --git a/usr/mallocator/main.c b/usr/mallocator/main.c
index 3ae49f1..7be0a6a 100644
--- a/usr/mallocator/main.c
+++ b/usr/mallocator/main.c
@@ -17,14 +17,17 @@
 
 #include <aos/aos.h>
 #include <aos/paging.h>
+#include <aos/deferred.h>
 
 #define NUM_SMALL_BUFFERS 128
-#define NUM_THREADS 16
+#define NUM_THREADS 512
 
 static struct thread* threads[NUM_THREADS];
 
 __attribute__((__used__))
 static int test_large_buffer(void * __args) {
+    barrelfish_usleep(rand() % 50 * 100000);
+
     //allocate a 256 MiB buffer
     debug_printf("allocating 256MiB buffer\n");
     char * big_buf = malloc(1<<28);