On Mon, Jan 28, 2019 at 2:51 AM Steffen Klassert <steffen.klass...@secunet.com> wrote: > > On Fri, Jan 25, 2019 at 08:57:00AM -0500, Willem de Bruijn wrote: > > On Fri, Jan 25, 2019 at 3:14 AM Steffen Klassert > > <steffen.klass...@secunet.com> wrote: > > > > > > On Mon, Jan 14, 2019 at 12:09:22PM -0500, Willem de Bruijn wrote: > > > > On Mon, Jan 14, 2019 at 7:50 AM Steffen Klassert > > > > <steffen.klass...@secunet.com> wrote: > > > > > On Sun, Dec 23, 2018 at 08:15:40PM -0500, Willem de Bruijn wrote: > > > > > > > > I don't think that the route lookup is needed. If listified is cheaper > > > > for local delivery, too, then we can make that the default unless a > > > > device is active with h/w offload and ip forwarding is enabled. If it > > > > isn't, then use it iff ip forwarding is enabled. I think it's fine to > > > > mispredict between the two in edge cases with netfilter mangling, as > > > > long as all paths can correctly handle both types of GRO packets. > > > > > > I'd need at least a route lookup for my usecase, because listified > > > GRO is always cheaper when a xfrm transformation is needed (even for > > > TCP). In this case is software GSO needed. So I'd need to either have > > > an early route lookup or maybe some early ingress hook where a route > > > lookup could be imlemented in. > > > > Could you use a similar system wide approach as what we discussed > > previous wrt hardware offload? Use listified only if (forwarding is enabled > > and no device is registered that implements h/w segmentation offload) or > > any path requires xfrm transformation (?). > > The xfrm transformation has to happen for the segments. So if we need to > do xfrm transformation in software, we need to do segmentation in > software too. I think that just forwarding is enabled and the presence > of a device that can do hardware segmentation offload is not a good > indicator. The more devices support hardware segmentation offload > the more likely is it that xfrm take a suboptimal path.
That's why I suggested OR any path requires xfrm. > We have to do a route lookup anyway, why not just do it early > in case forwarding is enabled? But actually, yes, that's true, so fine, too.
