From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Yang, Zhiyong" Subject: Re: [PATCH 4/5] net/vhost: remove limit of vhost TX burst size Date: Wed, 1 Mar 2017 13:24:16 +0000 Message-ID: References: <1487926101-4637-1-git-send-email-zhiyong.yang@intel.com> <1487926101-4637-5-git-send-email-zhiyong.yang@intel.com> <0ae31488-1ea6-abb8-7bd0-b5526dc9fc9f@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Cc: "yuanhan.liu@linux.intel.com" To: Maxime Coquelin , "dev@dpdk.org" Return-path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by dpdk.org (Postfix) with ESMTP id A023E6787 for ; Wed, 1 Mar 2017 14:24:22 +0100 (CET) In-Reply-To: <0ae31488-1ea6-abb8-7bd0-b5526dc9fc9f@redhat.com> Content-Language: en-US List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Hi, Maxime: > -----Original Message----- > From: Maxime Coquelin [mailto:maxime.coquelin@redhat.com] > Sent: Wednesday, March 1, 2017 5:44 PM > To: Yang, Zhiyong ; dev@dpdk.org > Cc: yuanhan.liu@linux.intel.com > Subject: Re: [PATCH 4/5] net/vhost: remove limit of vhost TX burst size >=20 >=20 >=20 > On 02/24/2017 09:48 AM, Zhiyong Yang wrote: > > 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 > > --- > > drivers/net/vhost/rte_eth_vhost.c | 24 ++++++++++++++++++++++-- > > 1 file changed, 22 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/net/vhost/rte_eth_vhost.c > > b/drivers/net/vhost/rte_eth_vhost.c > > index e98cffd..1e1fa34 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[] =3D { > > ETH_VHOST_IFACE_ARG, > > @@ -434,8 +435,27 @@ eth_vhost_tx(void *q, struct rte_mbuf **bufs, > uint16_t nb_bufs) > > goto out; > > > > /* Enqueue packets to guest RX queue */ > > - nb_tx =3D rte_vhost_enqueue_burst(r->vid, > > - r->virtqueue_id, bufs, nb_bufs); > > + if (likely(nb_bufs <=3D VHOST_MAX_PKT_BURST)) > > + nb_tx =3D rte_vhost_enqueue_burst(r->vid, r->virtqueue_id, > > + bufs, nb_bufs); > > + else { > > + uint16_t nb_send =3D nb_bufs; > > + > > + while (nb_send) { > > + uint16_t nb_pkts; > > + uint16_t num =3D (uint16_t)RTE_MIN(nb_send, > > + VHOST_MAX_PKT_BURST); > > + > > + nb_pkts =3D rte_vhost_enqueue_burst(r->vid, > > + r->virtqueue_id, > > + &bufs[nb_tx], num); > > + > > + nb_tx +=3D nb_pkts; > > + nb_send -=3D nb_pkts; > > + if (nb_pkts < num) > > + break; > > + } > > + } > It looks like the if/else could be avoided, but maybe you did so for > performance reason? > If this is the case, maybe you could add a comment or at least state this= in the > commit message. Yes, you are right. if/else can be avoided and code will look more clean. I choose performance between them.=20 Comments will be added in V2 here. Thanks Zhiyong >=20 > Thanks, > Maxime > > > > r->stats.pkts +=3D nb_tx; > > r->stats.missed_pkts +=3D nb_bufs - nb_tx; > >