[dpdk-dev] [RFC 5/6] vhost: minor refinement

Tiwei Bie tiwei.bie at intel.com
Tue Jul 18 17:40:20 CEST 2017


Manually prefetch the first desc in dequeue path.

Signed-off-by: Tiwei Bie <tiwei.bie at intel.com>
---
 lib/librte_vhost/virtio_net.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 0888d2b..08d53d9 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -1259,6 +1259,7 @@ vhost_dequeue_burst_1_1(struct virtio_net *dev, struct vhost_virtqueue *vq,
 
 	vq->last_used_idx = desc_idx;
 	if (likely(i)) {
+		rte_prefetch0(&desc[head_idx & (vq->size - 1)]);
 		for (desc_idx = head_idx + 1;
 		     desc_idx != vq->last_used_idx;
 		     desc_idx++) {
-- 
2.7.4



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