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From: Ouyang Changchun <changchun.ouyang@intel.com>
To: dev@dpdk.org
Subject: [dpdk-dev] [PATCH] virtio: Fix vring entry number issue
Date: Thu,  4 Sep 2014 14:34:59 +0800	[thread overview]
Message-ID: <1409812499-15656-1-git-send-email-changchun.ouyang@intel.com> (raw)

Fix one issue in virtio TX: it needs one more vring entry to hold the virtio header when transmitting packets, it is used later to determine whether to free more entries from used vring.

Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com>
Reviewed-by: Huawei Xie <huawei.xie@intel.com>
Tested-by: Jingguo Fu <jingguox.fu@intel.com>
---
 lib/librte_pmd_virtio/virtio_rxtx.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/librte_pmd_virtio/virtio_rxtx.c b/lib/librte_pmd_virtio/virtio_rxtx.c
index 0b10108..b1c189c 100644
--- a/lib/librte_pmd_virtio/virtio_rxtx.c
+++ b/lib/librte_pmd_virtio/virtio_rxtx.c
@@ -699,7 +699,8 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 	num = (uint16_t)(likely(nb_used < VIRTIO_MBUF_BURST_SZ) ? nb_used : VIRTIO_MBUF_BURST_SZ);
 
 	while (nb_tx < nb_pkts) {
-		int need = tx_pkts[nb_tx]->pkt.nb_segs - txvq->vq_free_cnt;
+		/* Need one more entry for virtio header. */
+		int need = tx_pkts[nb_tx]->pkt.nb_segs - txvq->vq_free_cnt + 1;
 		int deq_cnt = RTE_MIN(need, (int)num);
 
 		num -= (deq_cnt > 0) ? deq_cnt : 0;
-- 
1.8.4.2

             reply	other threads:[~2014-09-04  6:30 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-04  6:34 Ouyang Changchun [this message]
2014-10-01 11:48 ` Olivier MATZ
2014-10-11  8:22   ` Ouyang, Changchun

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