diff --git a/init.c b/init.c
index b4b4abe..911ee32 100644
--- a/init.c
+++ b/init.c
@@ -171,8 +171,8 @@
 {
 	struct thread_options *o = &td->o;
 
-	if (!o->rwmixread && o->rwmixwrite)
-		o->rwmixread = 100 - o->rwmixwrite;
+	if (o->rwmix[DDIR_READ] + o->rwmix[DDIR_WRITE] > 100)
+		o->rwmix[DDIR_WRITE] = 100 - o->rwmix[DDIR_READ];
 
 	if (o->write_iolog_file && o->read_iolog_file) {
 		log_err("fio: read iolog overrides write_iolog\n");