net/i40e: improve vector Tx performance

For i40e vector Tx path, if tx_offload is set as FAST_FREE_MBUF mode,
no mbuf fast free operations are executed. To fix this, add mbuf fast
free mode for vector Tx path.

Furthermore, for i40e vector Tx path, if implement FAST_FREE_MBUF mode,
it means per-queue all mbufs come from the same mempool and have
refcnt = 1. Thus we can use bulk free of the buffers when mbuf fast free
mode is enabled.

For vector path in arm platform:
In n1sdp, performance is improved by 18.4%;
In thunderx2, performance is improved by 23%.

For vector path in x86 platform:
No performance changes.

Suggested-by: Ruifeng Wang <ruifeng.wang@arm.com>
Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>

diff --git a/drivers/net/i40e/i40e_rxtx_vec_common.h b/drivers/net/i40e/i40e_rxtx_vec_common.h
index 16fcf0a..f52ed98 100644 (file)
--- a/drivers/net/i40e/i40e_rxtx_vec_common.h
+++ b/drivers/net/i40e/i40e_rxtx_vec_common.h
@@ -99,6 +99,16 @@ i40e_tx_free_bufs(struct i40e_tx_queue *txq)
          * tx_next_dd - (tx_rs_thresh-1)
          */
        txep = &txq->sw_ring[txq->tx_next_dd - (n - 1)];
+
+       if (txq->offloads & DEV_TX_OFFLOAD_MBUF_FAST_FREE) {
+               for (i = 0; i < n; i++) {
+                       free[i] = txep[i].mbuf;
+                       txep[i].mbuf = NULL;
+               }
+               rte_mempool_put_bulk(free[0]->pool, (void **)free, n);
+               goto done;
+       }
+
        m = rte_pktmbuf_prefree_seg(txep[0].mbuf);
        if (likely(m != NULL)) {
                free[0] = m;
@@ -126,6 +136,7 @@ i40e_tx_free_bufs(struct i40e_tx_queue *txq)
                }
        }
 
+done:
        /* buffers were freed, update counters */
        txq->nb_tx_free = (uint16_t)(txq->nb_tx_free + txq->tx_rs_thresh);
        txq->tx_next_dd = (uint16_t)(txq->tx_next_dd + txq->tx_rs_thresh);