Date: Thu, 30 Jan 2014 22:32:32 -0500 (EST) From: Rick Macklem <rmacklem@uoguelph.ca> To: Adrian Chadd <adrian@freebsd.org> Cc: FreeBSD Net <freebsd-net@freebsd.org> Subject: Re: 64K NFS I/O generates a 34mbuf list for TCP which breaks TSO Message-ID: <1856284835.584005.1391139152133.JavaMail.root@uoguelph.ca> In-Reply-To: <CAJ-VmonGR-KQBGyKCUn=k8PDH3skB5N8br3JyDTD27%2Bz=UwJJw@mail.gmail.com>
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------=_Part_584003_402802933.1391139152131 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Adrian Chadd wrote: > On 30 January 2014 07:06, Rick Macklem <rmacklem@uoguelph.ca> wrote: > > Hi, just adding one more idea on what to do about this > > to the list: > > - Add a if_hw_tsomaxseg and modify the loop in tcp_output() > > so that it uses both if_hw_tsomax and if_hw_tsomaxseg to > > decide how much to hand to the device driver in each mbuf list. > > (I haven't looked to see how easy it would be to change this > > loop.) > > I don't think that's a hack. I think adding that and setting > tsomaxseg > to say 30 for now would be a good comprimise. > Well, my TCP is very rusty and I have no way to test it (I don't have anything that does TSO), but I've attached a stab at a patch to do this. Maybe it can be used as a starting point for this, if others think it makes sense. The "#ifdef notyet" in the patch would become something like: # if __FreeBSD_version >= NNNN when a change to add if_hw_tsomaxseg is done, was what I was thinking. rick > > > -a > _______________________________________________ > 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" > ------=_Part_584003_402802933.1391139152131 Content-Type: text/x-patch; name=tsomaxseg.patch Content-Disposition: attachment; filename=tsomaxseg.patch Content-Transfer-Encoding: base64 LS0tIGtlcm4vdWlwY19zb2NrYnVmLmMuc2F2CTIwMTQtMDEtMzAgMjA6Mjc6MTcuMDAwMDAwMDAw IC0wNTAwCisrKyBrZXJuL3VpcGNfc29ja2J1Zi5jCTIwMTQtMDEtMzAgMjI6MTI6MDguMDAwMDAw MDAwIC0wNTAwCkBAIC05NjUsNiArOTY1LDM5IEBAIHNic25kcHRyKHN0cnVjdCBzb2NrYnVmICpz YiwgdV9pbnQgb2ZmLCAKIH0KIAogLyoKKyAqIFJldHVybiB0aGUgZmlyc3QgbWJ1ZiBmb3IgdGhl IHByb3ZpZGVkIG9mZnNldC4KKyAqLworc3RydWN0IG1idWYgKgorc2JzbmRtYnVmKHN0cnVjdCBz 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