diff --git a/runtime/starpu/control/runtime_control.c b/runtime/starpu/control/runtime_control.c
index d455238b7e26a5192a57ab69f658d2200d2ffea9..6ee39b52644b48dc36fc8ea4c32e205580d6fe65 100644
--- a/runtime/starpu/control/runtime_control.c
+++ b/runtime/starpu/control/runtime_control.c
@@ -76,7 +76,9 @@ int RUNTIME_init( CHAM_context_t *chamctxt,
         return 0;
     }
 
-    conf->ncpus = ncpus;
+    if (ncpus != -1) {
+        conf->ncpus = ncpus;
+    }
     conf->ncuda = ncudas;
     conf->nopencl = 0;