Date: Sat, 20 Sep 2014 18:47:39 +0200 From: Stefano Garzarella <stefanogarzarella@gmail.com> To: Freddie Cash <fjwcash@gmail.com> Cc: Hans Petter Selasky <hps@selasky.org>, Adrian Chadd <adrian@freebsd.org>, "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, George Neville-Neil <gnn@neville-neil.com>, freebsd-current <freebsd-current@freebsd.org>, Luigi Rizzo <rizzo@iet.unipi.it> Subject: Re: [RFC] Patch to add Software/Generic Segmentation Offload (GSO) support in FreeBSD Message-ID: <CAO0mX5ba6S-9mVe0SZGT=QFguwz_RT-UVoosxFNxEPOrSV%2Bfeg@mail.gmail.com> In-Reply-To: <CAOjFWZ73X=v6=KgeF%2BTpRCAe=KbXm1Yp3iKpKDeqyKK12Ejtwg@mail.gmail.com> References: <CAO0mX5bDoCe8oRNmd%2BUBbr4bJcgQEzhAQKyTsyxEQciyvGTdgQ@mail.gmail.com> <CAJ-VmomY7M2h2Bbuu5BXRUYFRMnKXezZfCNbNWGFHACuFwNDmg@mail.gmail.com> <CAO0mX5Zdt487=entnjrMjxpt%2BLhKTNkS=sUHsnyVDYr_PXyS7Q@mail.gmail.com> <5419EE95.40600@selasky.org> <CAO0mX5ZGGY5fMmc%2BTFrknFrGrErrB7fx=f%2BSDMRg7oTTVHTRVg@mail.gmail.com> <CAOjFWZ73X=v6=KgeF%2BTpRCAe=KbXm1Yp3iKpKDeqyKK12Ejtwg@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Hi Freddie, this is a preliminary version and, for now, we have not analyzed all aspects. Thanks for your suggestion. We will try to analyze how the GSO affects IPFW as soon as possible. Cheers, Stefano 2014-09-18 17:27 GMT+02:00 Freddie Cash <fjwcash@gmail.com>: > On Thu, Sep 18, 2014 at 7:16 AM, Stefano Garzarella < > stefanogarzarella@gmail.com> wrote: > >> I saw the discussion about TSO, but the GSO is a software >> implementation unrelated with the hardware. >> Furthermore, if the TSO is enabled (and supported by the NIC), the GSO i= s >> not executed, because is useless. >> >> After the execution of the GSO, the packets, that are passed to the devi= ce >> driver, are smaller (or equal) than MTU, so the TSO is unnecessary. For >> this reason the GSO doesn't look neither "ifp->if_hw_tsomax" nor hardwar= e >> segment limits. >> >> The GSO is very useful when you can't use the TSO. >> > > =E2=80=8BHow does GSO affect IPFW, specifically the libalias(3)-based, in= -kernel > NAT? The ipfw(8) man page mentions that it doesn't play nicely with > hardware-based TSO, and that one should disable TSO when using IPFW NAT. > > Will the software-based GSO play nicely with IPFW NAT?=E2=80=8B Will it = make any > difference to packet throughput through IPFW? > > Or is it still way too early in development to be worrying about such > things? :) > > -- > Freddie Cash > fjwcash@gmail.com > --=20 *Stefano Garzarella* stefano.garzarella@gmail.com
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAO0mX5ba6S-9mVe0SZGT=QFguwz_RT-UVoosxFNxEPOrSV%2Bfeg>