[PATCH v3 4/5] net/vhost: remove limit of vhost TX burst size

[Zhiyong Yang <zhiyong.yang@intel.com>]

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

Cc: yuanhan.liu@linux.intel.com
Cc: maxime.coquelin@redhat.com
Signed-off-by: Zhiyong Yang <zhiyong.yang@intel.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
---
 drivers/net/vhost/rte_eth_vhost.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/net/vhost/rte_eth_vhost.c b/drivers/net/vhost/rte_eth_vhost.c
index abe91c7..2a38b19 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,
@@ -424,6 +425,7 @@ 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 = nb_bufs;
 
 	if (unlikely(rte_atomic32_read(&r->allow_queuing) == 0))
 		return 0;
@@ -434,8 +436,19 @@ 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);
+	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