diff mbox

[dpdk-dev,v5,4/6] vhost: add desc prefetch

Message ID 1473392368-84903-5-git-send-email-zhihong.wang@intel.com (mailing list archive)
State Superseded, archived
Delegated to: Yuanhan Liu
Headers

Commit Message

Zhihong Wang Sept. 9, 2016, 3:39 a.m. UTC 
  This patch adds descriptor prefetch to hide cache access latency.

Signed-off-by: Zhihong Wang <zhihong.wang@intel.com>
---
 lib/librte_vhost/virtio_net.c | 6 ++++++
 1 file changed, 6 insertions(+)
diff mbox

Patch

diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 6f63968..b38f18f 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -302,6 +302,12 @@  rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
 	/* start enqueuing packets 1 by 1 */
 	avail_idx = *((volatile uint16_t *)&vq->avail->idx);
 	while (pkt_left && avail_idx != vq->last_used_idx) {
+		/* prefetch the next desc */
+		if (pkt_left > 1 && avail_idx != vq->last_used_idx + 1)
+			rte_prefetch0(&vq->desc[vq->avail->ring[
+					(vq->last_used_idx + 1) &
+					(vq->size - 1)]]);
+
 		if (enqueue_packet(dev, vq, avail_idx, pkts[pkt_idx],
 					is_mrg_rxbuf))
 			break;