From: Damjan Marion <damarion@cisco.com>
Date: Wed, 10 Jun 2015 22:19:25 +0000 (+0200)
Subject: i40e: prefetch next mbuf in Rx init loop
X-Git-Tag: spdx-start~8788
X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=b91fe0f7ad601848eb468dcbb2159b9a0deaf98a;p=dpdk.git

i40e: prefetch next mbuf in Rx init loop

This patch improves performance of Rx with i40e devices.

Signed-off-by: Damjan Marion <damarion@cisco.com>
Acked-by: Helin Zhang <helin.zhang@intel.com>
[Thomas: apply Helin's comments]
---

diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c
index 6daf1dca19..21b8edd38b 100644
--- a/drivers/net/i40e/i40e_rxtx.c
+++ b/drivers/net/i40e/i40e_rxtx.c
@@ -813,6 +813,10 @@ i40e_rx_alloc_bufs(struct i40e_rx_queue *rxq)
 
 	rxdp = &rxq->rx_ring[alloc_idx];
 	for (i = 0; i < rxq->rx_free_thresh; i++) {
+		if (likely(i < (rxq->rx_free_thresh - 1)))
+			/* Prefetch next mbuf */
+			rte_prefetch0(rxep[i + 1].mbuf);
+
 		mb = rxep[i].mbuf;
 		rte_mbuf_refcnt_set(mb, 1);
 		mb->next = NULL;