Merge pull request openucx#8348 from dmitrygx/topic/uct/dc_fc_hard_req

UCT/IB/DC: Resend FC_HARD_REQ instead of scheduling EP on waitq

Author: yosefe

src/uct/ib/dc/dc_mlx5.inl

@@ -41,16 +41,15 @@ uct_dc_mlx5_get_arbiter_params(uct_dc_mlx5_iface_t *iface, uct_dc_mlx5_ep_t *ep,
 }
 
 static UCS_F_ALWAYS_INLINE void
-uct_dc_mlx5_ep_schedule(uct_dc_mlx5_iface_t *iface, uct_dc_mlx5_ep_t *ep,
-                        int force)
+uct_dc_mlx5_ep_schedule(uct_dc_mlx5_iface_t *iface, uct_dc_mlx5_ep_t *ep)
 {
     if (ep->dci == UCT_DC_MLX5_EP_NO_DCI) {
         /* no dci:
          * Do not grab dci here. Instead put the group on dci allocation
          * arbiter. This way we can assure fairness between all eps waiting for
          * dci allocation. Relevant for dcs and dcs_quota policies.
          */
-        uct_dc_mlx5_iface_schedule_dci_alloc(iface, ep, force);
+        uct_dc_mlx5_iface_schedule_dci_alloc(iface, ep);
     } else {
         uct_dc_mlx5_iface_dci_sched_tx(iface, ep);
     }
@@ -84,5 +83,5 @@ uct_dc_mlx5_ep_pending_common(uct_dc_mlx5_iface_t *iface, uct_dc_mlx5_ep_t *ep,
         return;
     }
 
-    uct_dc_mlx5_ep_schedule(iface, ep, 0);
+    uct_dc_mlx5_ep_schedule(iface, ep);
 }

src/uct/ib/dc/dc_mlx5_ep.c

@@ -1572,17 +1572,12 @@ static unsigned uct_dc_mlx5_ep_fc_hard_req_progress(void *arg)
      * resend FC_HARD_REQ packet to make sure a peer will resend FC_PURE_GRANT
      * packet in case of failure on the remote FC endpoint */
     kh_foreach_key(&iface->tx.fc_hash, ep_key, {
-        ep = (uct_dc_mlx5_ep_t*)ep_key;
-
-        /* Allocate DCI for the endpoint to schedule the endpoint to DCI wait
-         * queue if there is free DCI */
-        status = uct_dc_mlx5_iface_dci_get(iface, ep);
-        ucs_assertv((status == UCS_OK) || (status == UCS_ERR_NO_RESOURCE),
-                    "%s", ucs_status_string(status));
-
-        /* Force DCI scheduling, since FC resources may never become available
-         * unless we send FC_HARD_REQ packet */
-        uct_dc_mlx5_ep_schedule(iface, ep, 1);
+        ep     = (uct_dc_mlx5_ep_t*)ep_key;
+        status = uct_dc_mlx5_ep_check_fc(iface, ep);
+        if ((status == UCS_OK) || (status == UCS_ERR_NO_RESOURCE)) {
+            ucs_warn("ep %p: flow-control check failed: %s", ep,
+                     ucs_status_string(status));
+        }
     })
 
     return 1;
@@ -1702,7 +1697,7 @@ void uct_dc_mlx5_ep_handle_failure(uct_dc_mlx5_ep_t *ep,
             /* Since DCI isn't assigned for the FC endpoint, schedule DCI
              * allocation for progressing possible FC_PURE_GRANT re-sending
              * operation which are scheduled on the pending queue */
-            uct_dc_mlx5_iface_schedule_dci_alloc(iface, ep, 0);
+            uct_dc_mlx5_iface_schedule_dci_alloc(iface, ep);
         }
     }
 

src/uct/ib/dc/dc_mlx5_ep.h

@@ -385,13 +385,12 @@ static inline int uct_dc_mlx5_iface_dci_ep_can_send(uct_dc_mlx5_ep_t *ep)
 
 static UCS_F_ALWAYS_INLINE
 void uct_dc_mlx5_iface_schedule_dci_alloc(uct_dc_mlx5_iface_t *iface,
-                                          uct_dc_mlx5_ep_t *ep, int force)
+                                          uct_dc_mlx5_ep_t *ep)
 {
     ucs_arbiter_t *waitq;
 
-    /* If FC window is empty and force scheduling wasn't requested, the group
-     * will be scheduled when grant is received */
-    if (force || uct_rc_fc_has_resources(&iface->super.super, &ep->fc)) {
+    /* If FC window is empty the group will be scheduled when grant is received */
+    if (uct_rc_fc_has_resources(&iface->super.super, &ep->fc)) {
         waitq = uct_dc_mlx5_iface_dci_waitq(iface, uct_dc_mlx5_ep_pool_index(ep));
         ucs_arbiter_group_schedule(waitq, &ep->arb_group);
     }
@@ -479,7 +478,7 @@ uct_dc_mlx5_iface_dci_put(uct_dc_mlx5_iface_t *iface, uint8_t dci_index)
      * move the group to the 'wait for dci alloc' state
      */
     ucs_arbiter_group_desched(uct_dc_mlx5_iface_tx_waitq(iface), &ep->arb_group);
-    uct_dc_mlx5_iface_schedule_dci_alloc(iface, ep, 0);
+    uct_dc_mlx5_iface_schedule_dci_alloc(iface, ep);
 }
 
 static inline void uct_dc_mlx5_iface_dci_alloc(uct_dc_mlx5_iface_t *iface, uct_dc_mlx5_ep_t *ep)