+receivers="127.0.0.1:4000 127.0.0.1:4001 127.0.0.1:4002 127.0.0.1:4003 127.0.0.1:4004"
+$exenv ./all2all_sender $receivers 512&
+$exenv ./all2all_sender $receivers 512&
+$exenv ./all2all_sender $receivers 512&
+$exenv ./all2all_sender $receivers 512&
+$exenv ./all2all_sender $receivers 512&
+