mlx5: use fast verbs interface for scattered Rx

This commit updates mlx5_rx_burst_sp() to use the fast verbs interface for
posting RX buffers just like mlx5_rx_burst(). Doing so avoids a loop in
libmlx5 and an indirect function call through libibverbs.

Note: recv_sg_list() is not implemented in the QP burst API, this commit is
only to prepare transition to the WQ-based API.

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>

diff --git a/drivers/net/mlx5/Makefile b/drivers/net/mlx5/Makefile
index 8b1e32b..2969045 100644 (file)
--- a/drivers/net/mlx5/Makefile
+++ b/drivers/net/mlx5/Makefile
@@ -119,6 +119,10 @@ mlx5_autoconf.h: $(RTE_SDK)/scripts/auto-config-h.sh
                HAVE_EXP_QUERY_DEVICE \
                infiniband/verbs.h \
                type 'struct ibv_exp_device_attr' $(AUTOCONF_OUTPUT)
+       $Q sh -- '$<' '$@' \
+               HAVE_EXP_QP_BURST_RECV_SG_LIST \
+               infiniband/verbs.h \
+               field 'struct ibv_exp_qp_burst_family.recv_sg_list' $(AUTOCONF_OUTPUT)
 
 mlx5.o: mlx5_autoconf.h
 

diff --git a/drivers/net/mlx5/mlx5_rxtx.c b/drivers/net/mlx5/mlx5_rxtx.c
index 623219d..8872f19 100644 (file)
--- a/drivers/net/mlx5/mlx5_rxtx.c
+++ b/drivers/net/mlx5/mlx5_rxtx.c
@@ -35,6 +35,7 @@
 #include <stdint.h>
 #include <string.h>
 #include <stdlib.h>
+#include <errno.h>
 
 /* Verbs header. */
 /* ISO C doesn't support unnamed structs/unions, disabling -pedantic. */
@@ -60,6 +61,7 @@
 #endif
 
 #include "mlx5.h"
+#include "mlx5_autoconf.h"
 #include "mlx5_utils.h"
 #include "mlx5_rxtx.h"
 #include "mlx5_defs.h"
@@ -600,9 +602,6 @@ mlx5_rx_burst_sp(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
        struct rxq_elt_sp (*elts)[rxq->elts_n] = rxq->elts.sp;
        const unsigned int elts_n = rxq->elts_n;
        unsigned int elts_head = rxq->elts_head;
-       struct ibv_recv_wr head;
-       struct ibv_recv_wr **next = &head.next;
-       struct ibv_recv_wr *bad_wr;
        unsigned int i;
        unsigned int pkts_ret = 0;
        int ret;
@@ -660,9 +659,6 @@ mlx5_rx_burst_sp(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
                                /* Increment dropped packets counter. */
                                ++rxq->stats.idropped;
 #endif
-                               /* Link completed WRs together for repost. */
-                               *next = wr;
-                               next = &wr->next;
                                goto repost;
                        }
                        ret = wc.byte_len;
@@ -671,9 +667,6 @@ mlx5_rx_burst_sp(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
                        break;
                len = ret;
                pkt_buf_len = len;
-               /* Link completed WRs together for repost. */
-               *next = wr;
-               next = &wr->next;
                /*
                 * Replace spent segments with new ones, concatenate and
                 * return them as pkt_buf.
@@ -770,26 +763,27 @@ mlx5_rx_burst_sp(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
                rxq->stats.ibytes += pkt_buf_len;
 #endif
 repost:
+#ifdef HAVE_EXP_QP_BURST_RECV_SG_LIST
+               ret = rxq->if_qp->recv_sg_list(rxq->qp,
+                                              elt->sges,
+                                              RTE_DIM(elt->sges));
+#else /* HAVE_EXP_QP_BURST_RECV_SG_LIST */
+               errno = ENOSYS;
+               ret = -1;
+#endif /* HAVE_EXP_QP_BURST_RECV_SG_LIST */
+               if (unlikely(ret)) {
+                       /* Inability to repost WRs is fatal. */
+                       DEBUG("%p: recv_sg_list(): failed (ret=%d)",
+                             (void *)rxq->priv,
+                             ret);
+                       abort();
+               }
                if (++elts_head >= elts_n)
                        elts_head = 0;
                continue;
        }
        if (unlikely(i == 0))
                return 0;
-       *next = NULL;
-       /* Repost WRs. */
-#ifdef DEBUG_RECV
-       DEBUG("%p: reposting %d WRs", (void *)rxq, i);
-#endif
-       ret = ibv_post_recv(rxq->qp, head.next, &bad_wr);
-       if (unlikely(ret)) {
-               /* Inability to repost WRs is fatal. */
-               DEBUG("%p: ibv_post_recv(): failed for WR %p: %s",
-                     (void *)rxq->priv,
-                     (void *)bad_wr,
-                     strerror(ret));
-               abort();
-       }
        rxq->elts_head = elts_head;
 #ifdef MLX5_PMD_SOFT_COUNTERS
        /* Increment packets counter. */