net/bnxt: optimize Tx batching

This patch adds a few optimizations to Tx batching. Instead of
specifying 'cmpl_next' to bnxt_start_xmit() as a hint to enable
completion for a given packet, request for completion on the last
successfully enqueued TxBD. This takes care of both success and
error cases. It eliminates 'cmpl_next' arg and related per-packet
condition checks around it.

Fixes: 5735eb241947 ("net/bnxt: support Tx batching")
Cc: stable@dpdk.org
Signed-off-by: Sriharsha Basavapatna <sriharsha.basavapatna@broadcom.com>
Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>

diff --git a/drivers/net/bnxt/bnxt_txr.c b/drivers/net/bnxt/bnxt_txr.c
index 1869341..b15778b 100644 (file)
--- a/drivers/net/bnxt/bnxt_txr.c
+++ b/drivers/net/bnxt/bnxt_txr.c
@@ -121,7 +121,6 @@ static inline uint32_t bnxt_tx_avail(struct bnxt_tx_queue *txq)
 static uint16_t bnxt_start_xmit(struct rte_mbuf *tx_pkt,
                                struct bnxt_tx_queue *txq,
                                uint16_t *coal_pkts,
-                               uint16_t *cmpl_next,
                                struct tx_bd_long **last_txbd)
 {
        struct bnxt_tx_ring_info *txr = txq->tx_ring;
@@ -184,12 +183,7 @@ static uint16_t bnxt_start_xmit(struct rte_mbuf *tx_pkt,
        txbd->opaque = *coal_pkts;
        txbd->flags_type = nr_bds << TX_BD_LONG_FLAGS_BD_CNT_SFT;
        txbd->flags_type |= TX_BD_SHORT_FLAGS_COAL_NOW;
-       if (!*cmpl_next) {
-               txbd->flags_type |= TX_BD_LONG_FLAGS_NO_CMPL;
-       } else {
-               *coal_pkts = 0;
-               *cmpl_next = false;
-       }
+       txbd->flags_type |= TX_BD_LONG_FLAGS_NO_CMPL;
        txbd->len = tx_pkt->data_len;
        if (tx_pkt->pkt_len >= 2014)
                txbd->flags_type |= TX_BD_LONG_FLAGS_LHINT_GTE2K;
@@ -415,10 +409,10 @@ static int bnxt_handle_tx_cp(struct bnxt_tx_queue *txq)
 uint16_t bnxt_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
                               uint16_t nb_pkts)
 {
-       struct bnxt_tx_queue *txq = tx_queue;
+       int rc;
        uint16_t nb_tx_pkts = 0;
        uint16_t coal_pkts = 0;
-       uint16_t cmpl_next = 0;
+       struct bnxt_tx_queue *txq = tx_queue;
        struct tx_bd_long *last_txbd = NULL;
 
        /* Handle TX completions */
@@ -432,27 +426,19 @@ uint16_t bnxt_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
 
        /* Handle TX burst request */
        for (nb_tx_pkts = 0; nb_tx_pkts < nb_pkts; nb_tx_pkts++) {
-               int rc;
-
-               /* Request a completion on the last packet */
-               cmpl_next |= (nb_pkts == nb_tx_pkts + 1);
                coal_pkts++;
                rc = bnxt_start_xmit(tx_pkts[nb_tx_pkts], txq,
-                                    &coal_pkts, &cmpl_next, &last_txbd);
+                                    &coal_pkts, &last_txbd);
 
-               if (unlikely(rc)) {
-                       /* Request a completion on the last successfully
-                        * enqueued packet
-                        */
-                       if (last_txbd)
-                               last_txbd->flags_type &=
-                                       ~TX_BD_LONG_FLAGS_NO_CMPL;
+               if (unlikely(rc))
                        break;
-               }
        }
 
-       if (nb_tx_pkts)
+       if (likely(nb_tx_pkts)) {
+               /* Request a completion on the last packet */
+               last_txbd->flags_type &= ~TX_BD_LONG_FLAGS_NO_CMPL;
                B_TX_DB(txq->tx_ring->tx_doorbell, txq->tx_ring->tx_prod);
+       }
 
        return nb_tx_pkts;
 }