Date: Thu, 31 May 2007 11:37:38 -0700 From: "Kip Macy" <kip.macy@gmail.com> To: "Bruce M. Simpson" <bms@freebsd.org>, "Jack Vogel" <jfvogel@gmail.com>, freebsd-net@freebsd.org Subject: Re: driver packet coalesce Message-ID: <b1fa29170705311137kb672d3al27457c2c72fd1e6@mail.gmail.com> In-Reply-To: <465F13F2.7070404@FreeBSD.org> References: <2a41acea0705301645x65e68e8q23c1b91d5f460ea3@mail.gmail.com> <20070531133828.GB4675@obelix.dsto.defence.gov.au> <2a41acea0705311056y7064ae79y6cd7a6a46d05c13b@mail.gmail.com> <465F13F2.7070404@FreeBSD.org>
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Bruce - All LRO implementations are currently on the host. On 5/31/07, Bruce M. Simpson <bms@freebsd.org> wrote: > Jack Vogel wrote: > > On 5/31/07, Wilkinson, Alex <alex.wilkinson@dsto.defence.gov.au> wrote: > >> 0n Wed, May 30, 2007 at 04:45:05PM -0700, Jack Vogel wrote: > >> > >> > Does any driver do this now? And if a driver were to coalesce > >> > packets and send something up the stack that violates mss > >> > will it barf? > >> > >> erm, what is meant by "coalesce" ? > >> > > combining packets before sending to the stack, aka LRO. > > Yup - the firmware for the card's LRO engine would have to know not to > coalesce packets not destined for the local host. I speculate many cards > are not smart enough to do this, and LRO is an all-or-nothing > proposition, as it's a technology designed to optimize for hosts, not > routers; see recent discussions/slanging matches on end2end. > > At the moment there is no central place where we track all layer 2 > addresses for which traffic should be delivered locally. This would > logically belong in struct ifnet, and clients e.g. CARP would have to be > taught to add their layer 2 endpoint addresses there. > > It seems acceptable to disable LRO if bridging is on and document this > behaviour. > > BMS > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >
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