[dpdk-dev] [PATCH] vhost: merge repeated loop in vhost Tx

[Gaoxiang Liu <gaoxiangliu0@163.com>]

To improve performance of vhost Tx, merge repeated loop in eth_vhost_tx.
Move "vlan insert" from eth_vhost_tx to virtio_dev_rx_packed
and virtio_dev_rx_split to reduce a loop iteration.

Fixes: f63d356ee993 ("net/vhost: insert/strip VLAN header in software")
Cc: stable@dpdk.org

Signed-off-by: Gaoxiang Liu <gaoxiangliu0@163.com>
---
 drivers/net/vhost/rte_eth_vhost.c | 25 ++++---------------------
 lib/vhost/virtio_net.c            | 21 +++++++++++++++++++++
 2 files changed, 25 insertions(+), 21 deletions(-)

diff --git a/drivers/net/vhost/rte_eth_vhost.c b/drivers/net/vhost/rte_eth_vhost.c
index a202931e9..ae2055097 100644
--- a/drivers/net/vhost/rte_eth_vhost.c
+++ b/drivers/net/vhost/rte_eth_vhost.c
@@ -428,7 +428,6 @@ eth_vhost_tx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
 {
 	struct vhost_queue *r = q;
 	uint16_t i, nb_tx = 0;
-	uint16_t nb_send = 0;
 	uint64_t nb_bytes = 0;
 	uint64_t nb_missed = 0;
 
@@ -440,33 +439,17 @@ eth_vhost_tx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
 	if (unlikely(rte_atomic32_read(&r->allow_queuing) == 0))
 		goto out;
 
-	for (i = 0; i < nb_bufs; i++) {
-		struct rte_mbuf *m = bufs[i];
-
-		/* Do VLAN tag insertion */
-		if (m->ol_flags & PKT_TX_VLAN_PKT) {
-			int error = rte_vlan_insert(&m);
-			if (unlikely(error)) {
-				rte_pktmbuf_free(m);
-				continue;
-			}
-		}
-
-		bufs[nb_send] = m;
-		++nb_send;
-	}
-
 	/* Enqueue packets to guest RX queue */
-	while (nb_send) {
+	while (nb_bufs) {
 		uint16_t nb_pkts;
-		uint16_t num = (uint16_t)RTE_MIN(nb_send,
+		uint16_t num = (uint16_t)RTE_MIN(nb_bufs,
 						 VHOST_MAX_PKT_BURST);
 
 		nb_pkts = rte_vhost_enqueue_burst(r->vid, r->virtqueue_id,
 						  &bufs[nb_tx], num);
 
 		nb_tx += nb_pkts;
-		nb_send -= nb_pkts;
+		nb_bufs -= nb_pkts;
 		if (nb_pkts < num)
 			break;
 	}
@@ -474,7 +457,7 @@ eth_vhost_tx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
 	for (i = 0; likely(i < nb_tx); i++)
 		nb_bytes += bufs[i]->pkt_len;
 
-	nb_missed = nb_bufs - nb_tx;
+	nb_missed = nb_bufs;
 
 	r->stats.pkts += nb_tx;
 	r->stats.bytes += nb_bytes;
diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
index b93482587..d62f5ca03 100644
--- a/lib/vhost/virtio_net.c
+++ b/lib/vhost/virtio_net.c
@@ -1223,6 +1223,16 @@ virtio_dev_rx_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
 		uint32_t pkt_len = pkts[pkt_idx]->pkt_len + dev->vhost_hlen;
 		uint16_t nr_vec = 0;
 
+		/* Do VLAN tag insertion */
+		if (pkts[pkt_idx]->ol_flags & PKT_TX_VLAN_PKT) {
+			int error = rte_vlan_insert(&pkts[pkt_idx]);
+			if (unlikely(error)) {
+				rte_pktmbuf_free(pkts[pkt_idx]);
+				pkts[pkt_idx] = NULL;
+				continue;
+			}
+		}
+
 		if (unlikely(reserve_avail_buf_split(dev, vq,
 						pkt_len, buf_vec, &num_buffers,
 						avail_head, &nr_vec) < 0)) {
@@ -1374,6 +1384,17 @@ virtio_dev_rx_packed(struct virtio_net *dev,
 	do {
 		rte_prefetch0(&vq->desc_packed[vq->last_avail_idx]);
 
+		/* Do VLAN tag insertion */
+		if (pkts[pkt_idx]->ol_flags & PKT_TX_VLAN_PKT) {
+			int error = rte_vlan_insert(&pkts[pkt_idx]);
+			if (unlikely(error)) {
+				rte_pktmbuf_free(pkts[pkt_idx]);
+				pkts[pkt_idx] = NULL;
+				pkt_idx++;
+				continue;
+			}
+		}
+
 		if (count - pkt_idx >= PACKED_BATCH_SIZE) {
 			if (!virtio_dev_rx_batch_packed(dev, vq,
 							&pkts[pkt_idx])) {
-- 
2.32.0