net/ena: perform Tx cleanup before sending packets

To increase likelihood that current burst will fit in the HW rings,
perform Tx cleanup before pushing packets to the HW. It may increase
latency a bit for sparse bursts, but the Tx flow now should be more
smooth.

It's also common order in the Tx burst function for other PMDs.

Signed-off-by: Michal Krawczyk <mk@semihalf.com>
Reviewed-by: Dawid Gorecki <dgr@semihalf.com>
Reviewed-by: Shai Brandes <shaibran@amazon.com>

diff --git a/drivers/net/ena/ena_ethdev.c b/drivers/net/ena/ena_ethdev.c
index 4b82372155b4adf9469f216bda4c674b18761cc3..ed3dd162ba58595a587b61926ac6b5705a299fd3 100644 (file)
--- a/drivers/net/ena/ena_ethdev.c
+++ b/drivers/net/ena/ena_ethdev.c
@@ -2776,6 +2776,10 @@ static uint16_t eth_ena_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
        }
 #endif
 
+       available_desc = ena_com_free_q_entries(tx_ring->ena_com_io_sq);
+       if (available_desc < tx_ring->tx_free_thresh)
+               ena_tx_cleanup(tx_ring);
+
        for (sent_idx = 0; sent_idx < nb_pkts; sent_idx++) {
                if (ena_xmit_mbuf(tx_ring, tx_pkts[sent_idx]))
                        break;
@@ -2784,9 +2788,6 @@ static uint16_t eth_ena_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
                        tx_ring->size_mask)]);
        }
 
-       available_desc = ena_com_free_q_entries(tx_ring->ena_com_io_sq);
-       tx_ring->tx_stats.available_desc = available_desc;
-
        /* If there are ready packets to be xmitted... */
        if (likely(tx_ring->pkts_without_db)) {
                /* ...let HW do its best :-) */
@@ -2795,9 +2796,6 @@ static uint16_t eth_ena_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts,
                tx_ring->pkts_without_db = false;
        }
 
-       if (available_desc < tx_ring->tx_free_thresh)
-               ena_tx_cleanup(tx_ring);
-
        tx_ring->tx_stats.available_desc =
                ena_com_free_q_entries(tx_ring->ena_com_io_sq);
        tx_ring->tx_stats.tx_poll++;