DPDK patches and discussions
 help / color / mirror / Atom feed
From: "Ouyang, Changchun" <changchun.ouyang@intel.com>
To: "Xie, Huawei" <huawei.xie@intel.com>, "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v4] virtio: Fix vring entry number issue
Date: Wed, 15 Oct 2014 03:14:00 +0000
Message-ID: <F52918179C57134FAEC9EA62FA2F96251186350A@shsmsx102.ccr.corp.intel.com> (raw)
In-Reply-To: <C37D651A908B024F974696C65296B57B0F2BCA95@SHSMSX101.ccr.corp.intel.com>

Hi Huawei,
I have v5 patch for this comment.
Thanks,
Changchun

> -----Original Message-----
> From: Xie, Huawei
> Sent: Wednesday, October 15, 2014 12:26 AM
> To: Ouyang, Changchun; dev@dpdk.org
> Subject: RE: [dpdk-dev] [PATCH v4] virtio: Fix vring entry number issue
> 
> 
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Ouyang
> Changchun
> > Sent: Tuesday, October 14, 2014 9:04 AM
> > To: dev@dpdk.org
> > Subject: [dpdk-dev] [PATCH v4] virtio: Fix vring entry number issue
> >
> >   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) {
> Could we put a branch hint to favor the fast path?
> >  			txm = tx_pkts[nb_tx];
> >  			/* Enqueue Packet buffers */
> >  			error = virtqueue_enqueue_xmit(txvq, txm);
> > --
> > 1.8.4.2

  reply	other threads:[~2014-10-15  3:06 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   ` [dpdk-dev] [PATCH v4] " Ouyang Changchun
2014-10-14 16:26     ` Xie, Huawei
2014-10-15  3:14       ` Ouyang, Changchun [this message]
2014-10-15  3:11     ` [dpdk-dev] [PATCH v5] " Ouyang Changchun
2014-10-15  6:34       ` Thomas Monjalon

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=F52918179C57134FAEC9EA62FA2F96251186350A@shsmsx102.ccr.corp.intel.com \
    --to=changchun.ouyang@intel.com \
    --cc=dev@dpdk.org \
    --cc=huawei.xie@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

DPDK patches and discussions

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://inbox.dpdk.org/dev/0 dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dev dev/ https://inbox.dpdk.org/dev \
		dev@dpdk.org
	public-inbox-index dev

Example config snippet for mirrors.
Newsgroup available over NNTP:
	nntp://inbox.dpdk.org/inbox.dpdk.dev


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git