[dpdk-dev] [RFC 27/29] vhost: various optimizations for Tx

[Tiwei Bie]

Signed-off-by: Tiwei Bie <tiwei....@intel.com>
---
 lib/librte_vhost/virtio_net.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 049b400..2d111a3 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -604,6 +604,8 @@ enqueue_pkt(struct virtio_net *dev, struct vring_desc_1_1 
*descs,
        if (unlikely(desc->len < dev->vhost_hlen) || !desc_addr)
                return -1;
 
+       desc->len = m->pkt_len + dev->vhost_hlen;
+
        rte_prefetch0((void *)(uintptr_t)desc_addr);
 
        hdr = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)desc_addr;
@@ -632,6 +634,7 @@ enqueue_pkt(struct virtio_net *dev, struct vring_desc_1_1 
*descs,
                                return -1;
                        }
 
+                       rte_panic("Shouldn't reach here\n");
                        /** NOTE: we should not come here with current
                            virtio-user implementation **/
                        desc_idx = (desc_idx + 1); // & (vq->size - 1);
@@ -680,6 +683,8 @@ vhost_enqueue_burst_1_1(struct virtio_net *dev, uint16_t 
queue_id,
 
        head_idx = vq->last_used_idx;
        desc = vq->desc_1_1;
+       count = RTE_MIN(count, (uint32_t)MAX_PKT_BURST);
+
        for (i = 0; i < count; i++) {
                /* XXX: there is an assumption that no desc will be chained */
                idx = vq->last_used_idx & (vq->size - 1);
@@ -693,11 +698,12 @@ vhost_enqueue_burst_1_1(struct virtio_net *dev, uint16_t 
queue_id,
        }
        count = i;
 
-       rte_smp_wmb();
-       for (i = 0; i < count; i++) {
-               idx = (head_idx + i) & (vq->size - 1);
-               desc[idx].flags &= ~DESC_HW;
-               desc[idx].len    = pkts[i]->pkt_len + dev->vhost_hlen;
+       if (count) {
+               rte_smp_wmb();
+               for (i = 0; i < count; i++) {
+                       idx = (head_idx + i) & (vq->size - 1);
+                       desc[idx].flags &= ~DESC_HW;
+               }
        }
 
        return count;
-- 
2.7.4