Date: Wed, 23 May 2012 11:27:49 +0530 From: Venkat Duvvuru <venkatduvvuru.ml@gmail.com> To: Jack Vogel <jfvogel@gmail.com> Cc: freebsd-net@freebsd.org, "Bjoern A. Zeeb" <bz@freebsd.org>, freebsd-questions@freebsd.org Subject: Re: LRO support for IPv6 Message-ID: <CAGdae7a%2Baf7RbijyKfMA94MfomNaTaD3M3PPmcFk%2B13SC9cMAg@mail.gmail.com> In-Reply-To: <CAFOYbcncAGPA6d7qh7bonGy2ijcApD_TQgqvSoM2Mbif-z8sYg@mail.gmail.com> References: <CAGdae7bcWqGbObygPdZwCyVG4Pe-0Fxq5_p19oCp61uzZ4N8xw@mail.gmail.com> <CAFOYbc=ng83L8iZ_N79edqhknOrDPqVA9ASMexW5-yU0vnduDQ@mail.gmail.com> <A8DB9672-6B84-4635-84B6-43CC98B2877F@FreeBSD.org> <CAFOYbckwRw4jazwqY1S7X2wiSdBBBPdg-Xk8ya99j1%2BWbqB=DA@mail.gmail.com> <72B744D5-3D24-4A56-907C-2A8F6620877B@FreeBSD.org> <CAGdae7ZX4M4NPnJ=3K1vA9TLPW22r2EpTic-Y4kJMyJQGn3zGw@mail.gmail.com> <CAFOYbcncAGPA6d7qh7bonGy2ijcApD_TQgqvSoM2Mbif-z8sYg@mail.gmail.com>
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Ok. I found the reason for the throughput drop in case of IPv6. Reason is that the "tcp check sum" calculation is mandated in case of IPv6 irrespective of whether the card is doing it or not (checksum offload). Is there a reason why freebsd is doing it that way? /Venkat On Tue, May 22, 2012 at 11:16 PM, Jack Vogel <jfvogel@gmail.com> wrote: > LRO is a huge win for 10G (as is TSO on the TX side), so odds are good its > behind the drop, > in any case you'll be able to test that soon :) > > Jack > > > > On Tue, May 22, 2012 at 10:35 AM, Venkat Duvvuru < > venkatduvvuru.ml@gmail.com> wrote: > >> Thanks for the response. >> >> I observed that there is a significant performance drop in case of IPv6 >> on the "rx" side. >> While I'm able to hit line rate ~9.5 Gbps on a 10gb NIC for IPv4..I could >> only get ~6 Gbps on the "rx" front for IPv6...However "tx" for IPv6 is on >> par with IPv4 hitting almost line rates. >> >> Could this be because of lack of LRO6?? >> >> Note: hwpmc profiling shows that most of the time is spent in the IPv6 >> stack code >> >> /Venkat >> On Tue, May 22, 2012 at 10:37 PM, Bjoern A. Zeeb <bz@freebsd.org> wrote: >> >>> >>> On 22. May 2012, at 17:04 , Jack Vogel wrote: >>> >>> > Oh, that's right, distracted with other projects and I forgot, now we >>> just need >>> > to have an LRO that works with forwarding eh :) >>> >>> That's a 6 line bainaid commit afterwards, basically returning form the >>> LRO queuing >>> function in case forwarding is turned on for that address family; a >>> proper solution >>> for long term can than be done whenever we feel like it. The above we >>> should have done >>> years ago;) >>> >>> >>> > You ROCK bz :) >>> > >>> > Jack >>> > >>> > >>> > On Tue, May 22, 2012 at 10:01 AM, Bjoern A. Zeeb <bz@freebsd.org> >>> wrote: >>> > >>> > On 22. May 2012, at 16:50 , Jack Vogel wrote: >>> > >>> > > The LRO code as it stands right now is IPV4 specific, it would be >>> nice to >>> > > extend it, one of >>> > > many improvements that may get done at some point. >>> > >>> > I am about to commit it to HEAD. Bear another few days with me; I know >>> > I am running late but committing new code had less prio than some other >>> > real life things currently. >>> > >>> > I'll also bring TSO6, etc... >>> >>> -- >>> Bjoern A. Zeeb You have to have visions! >>> It does not matter how good you are. It matters what good you do! >>> >>> >> >
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