Correct size of tiobench profile

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/init.c b/init.c
index 26c7d1d..4bb9172 100644
--- a/init.c
+++ b/init.c
@@ -137,7 +137,7 @@
 };
 
 static const char *tiobench_opts[] = {
-	"buffered=0", "size=256*$mb_memory", "bs=4k", "timeout=600",
+	"buffered=0", "size=4*1024*$mb_memory", "bs=4k", "timeout=600",
 	"numjobs=4", "group_reporting", "thread", "overwrite=1",
 	"filename=.fio.tio.1:.fio.tio.2:.fio.tio.3:.fio.tio.4",
 	"name=seqwrite", "rw=write", "end_fsync=1",