Re: [dpdk-dev] [PATCH] vhost: support UDP Fragmentation Offload

[Neil Horman <nhorman@tuxdriver.com>]

On Tue, Nov 21, 2017 at 07:41:00AM +0000, Hu, Jiayu wrote:
> Hi Stephen,
> 
> > -----Original Message-----
> > From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> > Sent: Tuesday, November 21, 2017 3:13 PM
> > To: Hu, Jiayu <jiayu.hu@intel.com>
> > Cc: dev@dpdk.org; yliu@fridaylinux.org; Tan, Jianfeng
> > <jianfeng.tan@intel.com>
> > Subject: Re: [dpdk-dev] [PATCH] vhost: support UDP Fragmentation Offload
> > 
> > On Tue, 21 Nov 2017 14:56:52 +0800
> > Jiayu Hu <jiayu.hu@intel.com> wrote:
> > 
> > > In virtio, UDP Fragmentation Offload (UFO) includes two parts: host UFO
> > > and guest UFO. Guest UFO means the frontend can receive large UDP
> > packets,
> > > and host UFO means the backend can receive large UDP packets. This patch
> > > supports host UFO and guest UFO for vhost-user.
> > >
> > > Signed-off-by: Jiayu Hu <jiayu.hu@intel.com>
> > 
> > This may no longer be a desirable feature to implement.
> > UFO was just deprecated and removed from Linux.
> > It had no useful benefit.
> 
> The main reason of supporting UFO is to make the backend live migration from
> vhost-net to vhost-user possible. Host and guest UFO are default features for virtio-net,
> and vhost-net supports both. But vhosy-user doesn't support them. If we want to
> migrate from vhost-net to vhost-user, this features gap would cause live migration fail.
> 
> Thanks,
> Jiayu
> 

Its not a widely used feature, but if it helps migrage people, its not a hard
feature to support

Acked-by: Neil Horman <nhorman@tuxdriver.com>