On Thu, Sep 19, 2019 at 9:07 AM Marcelo Ricardo Leitner <marcelo.leit...@gmail.com> wrote: > > On Thu, Sep 19, 2019 at 08:55:22AM -0400, Willem de Bruijn wrote: > > On Wed, Sep 18, 2019 at 12:58 PM Marcelo Ricardo Leitner > > <marcelo.leit...@gmail.com> wrote: > > > > > > On Wed, Sep 18, 2019 at 12:17:08PM -0400, Willem de Bruijn wrote: > > > > On Wed, Sep 18, 2019 at 3:25 AM Steffen Klassert > > > > <steffen.klass...@secunet.com> wrote: > > > > > > > > > > This patchset adds support to do GRO/GSO by chaining packets > > > > > of the same flow at the SKB frag_list pointer. This avoids > > > > > the overhead to merge payloads into one big packet, and > > > > > on the other end, if GSO is needed it avoids the overhead > > > > > of splitting the big packet back to the native form. > > > > > > > > > > Patch 1 Enables UDP GRO by default. > > > > > > > > > > Patch 2 adds a netdev feature flag to enable listifyed GRO, > > > > > this implements one of the configuration options discussed > > > > > at netconf 2019. > > > > > > > > > > Patch 3 adds a netdev software feature set that defaults to off > > > > > and assigns the new listifyed GRO feature flag to it. > > > > > > > > > > Patch 4 adds the core infrastructure to do fraglist GRO/GSO. > > > > > > > > > > Patch 5 enables UDP to use fraglist GRO/GSO if configured and no > > > > > GRO supported socket is found. > > > > > > > > Very nice feature, Steffen. Aside from questions around performance, > > > > my only question is really how this relates to GSO_BY_FRAGS. > > > > > > They do the exact same thing AFAICT: they GSO according to a > > > pre-formatted list of fragments/packets, and not to a specific size > > > (such as MSS). > > > > > > > > > > > More specifically, whether we can remove that in favor of using your > > > > new skb_segment_list. That would actually be a big first step in > > > > simplifying skb_segment back to something manageable. > > > > > > The main issue (that I know) on obsoleting GSO_BY_FRAGS is that > > > dealing with frags instead of frag_list was considered easier to be > > > offloaded, if ever attempted. So this would be a step back on that > > > aspect. Other than this, it should be doable. > > > > But GSO_BY_FRAGS also uses frag_list, not frags? > > /me is scratching his head. > My bad. I thought it was already using frags. Thanks. > > > > > And list_skb->len for mss. > > Which stands more for 'current frag size', yes. > (list_skb, not head_skb)
Great. I thought I missed something :) Frags might be cheaper from an allocation point. If at some point going down that road. But in the meantime, it looks like we can handle these too with skb_segment_list, then (not necessarily in the initial patch set).
