Date: Tue, 20 Jun 2000 16:42:12 -0700 (PDT) From: Matthew Jacob <mjacob@feral.com> To: Dave Preece <dave.preece@kbgroup.co.nz> Cc: Marc Nicholas <marc@netstor.com>, freebsd-hackers@FreeBSD.ORG Subject: RE: IP checksum offloading with intel 82559 fast ethernet. Message-ID: <Pine.BSF.4.05.10006201637470.12031-100000@semuta.feral.com> In-Reply-To: <67B808B0DD93D211ABEE0000B498356B02BCD2@internet.kbgroup.co.nz>
next in thread | previous in thread | raw e-mail | index | archive | help
(I'm the wx author)... I want to do checksum offloading too at some point. There's been some work done on this by Andrew Gallatin and Ken Merry amongst others insofar as I recall, but I don't believe it's been checked in. Let me see if I can dig up the mail.. Everyone's at Usenix this week && next, so don't expect too much of a response. -matt On Wed, 21 Jun 2000, Dave Preece wrote: > > Don't some of the Gigabit FreeBSD drivers actually utilize > > the on-board > > checksum processing??? > > Hmmmm, can't see anything specific.... Looking at if_wx.c we have a function > wx_start(ifp) where ifp is an ifnet pointer. ifnet has a member if_snd, of > type ifqueue (according to the man page). And ifqueue is a safe looking > memory buffer, but no actual statement as to whether we are expected to put > raw packets on the queue or.... what. Presumably entire ethernet frames are > put on the queue so we can spoof ethernet mac addresses occasionally - but > no real way of indicating to the card that we have put an IP packet on with > no checksum (and could you calculate it for me please). > > As an aside, if checksum calculations were offloadable via a call across PCI > (i.e. send raw packet, get packet back with tcp calculated, queue packet for > delivery), then it's a bit touch and go as to whether this is actually a > good idea - given that we'll start to load up PCI quite badly doing this. > > > Nice to see someone keeping our drivers fresh :-) > > Oh, no. I wish. I'm well off the end of my abilities here, but clearly into > what I 'owe' the community in general. Hopefully I'll get there at some > time. > > > -marc > > Dave > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?Pine.BSF.4.05.10006201637470.12031-100000>