[dpdk-dev] [PATCH] i40e: prefetch next mbuf in rx alloc code

[Damjan Marion]

This patch improves performance of vectored rx on i40e devices.

Signed-off-by: Damjan Marion <damarion at cisco.com>
---
 drivers/net/i40e/i40e_rxtx.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c
index 2de0ac4..152e9e6 100644
--- a/drivers/net/i40e/i40e_rxtx.c
+++ b/drivers/net/i40e/i40e_rxtx.c
@@ -778,6 +778,11 @@ i40e_rx_alloc_bufs(struct i40e_rx_queue *rxq)

        rxdp = &rxq->rx_ring[alloc_idx];
        for (i = 0; i < rxq->rx_free_thresh; i++) {
+
+               /* Prefetch next mbuf */
+               if (i < (rxq->rx_free_thresh - 1))
+                       rte_prefetch0 (rxep[i+1].mbuf);
+
                mb = rxep[i].mbuf;
                rte_mbuf_refcnt_set(mb, 1);
                mb->next = NULL;
-- 
2.1.4