[dpdk-dev] [PATCH v3 6/7] vhost: prefetch first descriptor in dequeue path

Maxime Coquelin maxime.coquelin at redhat.com
Wed Jun 27 16:49:58 CEST 2018


Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
---
 lib/librte_vhost/virtio_net.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 404968cd0..ff6fa8d61 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -1082,6 +1082,8 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
 		vq->shadow_used_idx = 0;
 	}
 
+	rte_prefetch0(&vq->avail->ring[vq->last_avail_idx & (vq->size - 1)]);
+
 	/*
 	 * Construct a RARP broadcast packet, and inject it to the "pkts"
 	 * array, to looks like that guest actually send such packet.
-- 
2.14.4



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