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From: "Ouyang, Changchun" <changchun.ouyang@intel.com>
To: 'Olivier MATZ' <olivier.matz@6wind.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v3] virtio: Fix vring entry number issue
Date: Tue, 14 Oct 2014 15:28:02 +0000
Message-ID: <F52918179C57134FAEC9EA62FA2F962511863212@shsmsx102.ccr.corp.intel.com> (raw)
In-Reply-To: <1413299561-31263-1-git-send-email-changchun.ouyang@intel.com>

Hi Olivier,

Any other comments for this v3 patch?

Thanks and regards,
Changchun

> -----Original Message-----
> From: Ouyang, Changchun
> Sent: Tuesday, October 14, 2014 11:13 PM
> To: dev@dpdk.org
> Cc: Cao, Waterman; Ouyang, Changchun
> Subject: [PATCH v3] virtio: Fix vring entry number issue
> 
> -- V1 change:
>   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.
> 
> -- 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.
> 
> -- V3 change:
>   Resolve compilation issue due to mbuf re-structure.
> 
> Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com>
> ---
>  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

  reply	other threads:[~2014-10-14 15:21 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 [this message]
2014-10-14 16:03   ` [dpdk-dev] [PATCH v4] " Ouyang Changchun
2014-10-14 16:26     ` 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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