[ovs-discuss] How to enable zero-copy feature of vhost-user ??

Loftus, Ciara ciara.loftus at intel.com
Wed Aug 2 09:12:05 UTC 2017


> 
> Hi Ciara,
> 
> Thank you for the infomation.
> IIUC, you should compile ovs again to use zero copy feature so far, right ?

Hi Tetsuro,

That's right. I might look into creating a patch to enable it during runtime. But for now, you need to apply the patch below & recompile.

Thanks,
Ciara

> 
> On 2017/08/02 17:04, Loftus, Ciara wrote:
> >>
> >> Hi,
> >>
> >> I heard that, about vhost-user interface,
> >> 0 copy rx is under development,
> >> but 0 copy tx from a vm is already supported with both vhost-user and
> >> ovs-dpdk.
> >>
> >> However, I couldn't find out how to enable that zero copy feature from
> >> the ovs document (/ovs/Documentation/topics/dpdk/vhost-user.rst)
> >>
> >> Could you inform me how to enable it or where I should refer about the
> >> feature ?
> >
> > Try this:
> >
> > diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
> > index ea17b97..9fdae46 100644
> > --- a/lib/netdev-dpdk.c
> > +++ b/lib/netdev-dpdk.c
> > @@ -944,6 +944,7 @@ netdev_dpdk_vhost_construct(struct netdev
> *netdev)
> >                dpdk_get_vhost_sock_dir(), name);
> >
> >       dev->vhost_driver_flags &= ~RTE_VHOST_USER_CLIENT;
> > +    dev->vhost_driver_flags |= RTE_VHOST_USER_DEQUEUE_ZERO_COPY;
> >       err = rte_vhost_driver_register(dev->vhost_id, dev-
> >vhost_driver_flags);
> >       if (err) {
> >           VLOG_ERR("vhost-user socket device setup failure for socket %s\n",
> >
> > Thanks,
> > Ciara
> >
> >>
> >> Thanks
> >>
> >> --
> >> Tetsuro Nakamura
> >>
> >> _______________________________________________
> >> discuss mailing list
> >> discuss at openvswitch.org
> >> https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
> >
> >
> 
> --
> Tetsuro Nakamura <nakamura.tetsuro at lab.ntt.co.jp>
> NTT Network Service Systems Laboratories
> TEL:0422 59 6914(National)/+81 422 59 6914(International)
> 3-9-11, Midori-Cho Musashino-Shi, Tokyo 180-8585 Japan
> 



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