diff --git a/test/unit/tcache_max.sh b/test/unit/tcache_max.sh
index 4480d733..0de75e4b 100644
--- a/test/unit/tcache_max.sh
+++ b/test/unit/tcache_max.sh
@@ -1,3 +1,3 @@
 #!/bin/sh
 
-export MALLOC_CONF="tcache_max:1024"
+export MALLOC_CONF="tcache_max:1024,tcache_gc_incr_bytes:939524096"