From: Ouyang Changchun <changchun.ouyang@intel.com> To: dev@dpdk.org Subject: [dpdk-dev] [PATCH v4] virtio: Fix vring entry number issue Date: Wed, 15 Oct 2014 00:03:54 +0800 Message-ID: <1413302634-848-1-git-send-email-changchun.ouyang@intel.com> (raw) In-Reply-To: <1413299561-31263-1-git-send-email-changchun.ouyang@intel.com> Fix one issue in virtio TX: it needs one more vring descriptor to hold the virtio header when transmitting packets, it is used later to determine whether to free more entries from used vring. It fixes failing to transmit any packet with 1 segment in the circumstance of only 1 descriptor in the vring free list. Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com> Reviewed-by: Olivier Matz <olivier.matz@6wind.com> --- -V4 change: Relocate those changelog and annotation here. -V3 change: Resolve compilation issue due to mbuf re-structure. -V2 change: Refine description, 'vring descriptor' is more accurate than 'vring entry'; Accordingly update test condition (it needs one more descriptor for virtio header) to put packets to transmit queue. -V1 change: Fix the vring descriptor issue in virtio TX, it needs one more vring descriptor to hold the virtio header. lib/librte_pmd_virtio/virtio_rxtx.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/lib/librte_pmd_virtio/virtio_rxtx.c b/lib/librte_pmd_virtio/virtio_rxtx.c index 0b10108..ac44c65 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 descriptor for virtio header. */ + int need = tx_pkts[nb_tx]->nb_segs - txvq->vq_free_cnt + 1; int deq_cnt = RTE_MIN(need, (int)num); num -= (deq_cnt > 0) ? deq_cnt : 0; @@ -708,7 +709,12 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts) deq_cnt--; } - if (tx_pkts[nb_tx]->pkt.nb_segs <= txvq->vq_free_cnt) { + need = (int)tx_pkts[nb_tx]->nb_segs - txvq->vq_free_cnt + 1; + /* + * Zero or negative value indicates it has enough free + * decriptors to transmit. + */ + if (need <= 0) { txm = tx_pkts[nb_tx]; /* Enqueue Packet buffers */ error = virtqueue_enqueue_xmit(txvq, txm); -- 1.8.4.2
next prev parent reply other threads:[~2014-10-14 15:59 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-10-11 8:05 [dpdk-dev] [PATCH v2] " Ouyang Changchun 2014-10-14 15:12 ` [dpdk-dev] [PATCH v3] " Ouyang Changchun 2014-10-14 15:28 ` Ouyang, Changchun 2014-10-14 16:03 ` Ouyang Changchun [this message] 2014-10-14 16:26 ` [dpdk-dev] [PATCH v4] " Xie, Huawei 2014-10-15 3:14 ` Ouyang, Changchun 2014-10-15 3:11 ` [dpdk-dev] [PATCH v5] " Ouyang Changchun 2014-10-15 6:34 ` Thomas Monjalon
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