[dpdk-dev] [PATCH 4/5] net/vhost: remove limit of vhost TX burst size

[Zhiyong Yang]

vhost removes limit of TX burst size(32 pkts) and supports to make
an best effort to transmit pkts.

Cc: yuanhan.liu at linux.intel.com
Cc: maxime.coquelin at redhat.com

Signed-off-by: Zhiyong Yang <zhiyong.yang at intel.com>
---
 drivers/net/vhost/rte_eth_vhost.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/net/vhost/rte_eth_vhost.c b/drivers/net/vhost/rte_eth_vhost.c
index e98cffd..1e1fa34 100644
--- a/drivers/net/vhost/rte_eth_vhost.c
+++ b/drivers/net/vhost/rte_eth_vhost.c
@@ -52,6 +52,7 @@
 #define ETH_VHOST_QUEUES_ARG		"queues"
 #define ETH_VHOST_CLIENT_ARG		"client"
 #define ETH_VHOST_DEQUEUE_ZERO_COPY	"dequeue-zero-copy"
+#define VHOST_MAX_PKT_BURST 32
 
 static const char *valid_arguments[] = {
 	ETH_VHOST_IFACE_ARG,
@@ -434,8 +435,27 @@ eth_vhost_tx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
 		goto out;
 
 	/* Enqueue packets to guest RX queue */
-	nb_tx = rte_vhost_enqueue_burst(r->vid,
-			r->virtqueue_id, bufs, nb_bufs);
+	if (likely(nb_bufs <= VHOST_MAX_PKT_BURST))
+		nb_tx = rte_vhost_enqueue_burst(r->vid, r->virtqueue_id,
+						bufs, nb_bufs);
+	else {
+		uint16_t nb_send = nb_bufs;
+
+		while (nb_send) {
+			uint16_t nb_pkts;
+			uint16_t num = (uint16_t)RTE_MIN(nb_send,
+					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;
+			if (nb_pkts < num)
+				break;
+		}
+	}
 
 	r->stats.pkts += nb_tx;
 	r->stats.missed_pkts += nb_bufs - nb_tx;
-- 
2.7.4