Per https://github.com/ofiwg/libfabric/issues/1217#issuecomment-131264316, you really need to specify FI_ORDER_SAS for both transmit and receive if you want to guarantee ordering on FI_EP_RDM endpoints (and you do; the MPI-style tagging interface doesn't make much sense unless the underlying fabric provider guarnatees ordering). Signed-off-by: Jeff Squyres <[email protected]> --- src/mpid/ch3/channels/nemesis/netmod/ofi/ofi_init.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/src/mpid/ch3/channels/nemesis/netmod/ofi/ofi_init.c b/src/mpid/ch3/channels/nemesis/netmod/ofi/ofi_init.c index 5de47b7..7c445ac 100644 --- a/src/mpid/ch3/channels/nemesis/netmod/ofi/ofi_init.c +++ b/src/mpid/ch3/channels/nemesis/netmod/ofi/ofi_init.c @@ -81,6 +81,8 @@ int MPID_nem_ofi_init(MPIDI_PG_t * pg_p, int pg_rank, char **bc_val_p, int *val_ hints->mode = FI_CONTEXT; hints->ep_attr->type = FI_EP_RDM; /* Reliable datagram */ hints->caps = FI_TAGGED; /* Tag matching interface */ + hints->tx_attr->msg_order = FI_ORDER_SAS; + hints->rx_attr->msg_order = FI_ORDER_SAS; hints->ep_attr->mem_tag_format = MEM_TAG_FORMAT; MPIU_Assert(pg_p->size < ((1 << MPID_RANK_BITS) - 1)); -- 2.4.3