Date: Thu, 24 Nov 2011 18:00:04 -0800 From: Jeremy Chadwick <freebsd@jdc.parodius.com> To: Kris Bauer <kristoph.bauer@gmail.com> Cc: Adrian Chadd <adrian@freebsd.org>, "freebsd-stable@freebsd.org List" <freebsd-stable@freebsd.org> Subject: Re: TCP Reassembly Issues Message-ID: <20111125020004.GA36109@icarus.home.lan> In-Reply-To: <CAPNZ-Wr8r%2Bz7u%2BT3xgY3dfwhEZkN27NebrXzaXmXmneWpMw8xA@mail.gmail.com> References: <CAPNZ-Wq38=F3o2hYuYF_unBj3SZQ52XhVhdcwQ8PE_vU9xc2YA@mail.gmail.com> <CABLqceRyohFFYtdnW%2Bt%2B63kwk00cbkJVz3oXWqrR=xijkg14CA@mail.gmail.com> <4ECE9914.6020502@turing.b2n.org> <CAPNZ-WrQdjFEErt6K1uEndSc082q8Q48VHvtbP=5cNXFw7H7Rg@mail.gmail.com> <1A5B3A48-7DF3-4018-A244-152BDE96299A@lassitu.de> <CAJ-VmokMrJipptQWjuhY5-41p=-P2-xc3ze1p4JKTXWz3MgtzA@mail.gmail.com> <CAPNZ-Wr8r%2Bz7u%2BT3xgY3dfwhEZkN27NebrXzaXmXmneWpMw8xA@mail.gmail.com>
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On Thu, Nov 24, 2011 at 07:13:39PM -0600, Kris Bauer wrote: > On Thu, Nov 24, 2011 at 5:35 PM, Adrian Chadd <adrian@freebsd.org> wrote: > > > Have you tried disabling the tcp offload features of your NIC? > > > > > > Adrian > > > > To test this, I added net.inet.tcp.tso=0 to sysctl.conf and restarted the > box; it didn't work. net.inet.tcp.reass.cursegments immediately started > climbing up and were exhausted within an hour. I think Adrian was referring to RXCSUM and TXCSUM on your NIC; TSO is another offloading feature. See ifconfig(8) for how to disable those. Be aware that disabling them in real-time (e.g. ifconfig xxx -rxcsum -txcsum) may cause problems; there are some NIC drivers on FreeBSD which do not like you doing this once the NIC has established link (meaning "reloading the driver" (for lack of better term) results in wonky behaviour). So you may instead want to add those hyphen-options to your ifconfig_XXX lines in /etc/rc.conf and reboot the box. If none of this solves the problem, then I consider this a priority 0 blocker (read: "all hands on deck") issue with the IP stack in FreeBSD 9.x and will need immediate attention. I would strongly recommend a developer or clueful end-user begin tracking down who committed all of these bits and CC them into the thread. I would start by looking who implemented the net.inet.tcp.reass.cursegments sysctl, because that isn't in RELENG_8 at all. -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, US | | Making life hard for others since 1977. PGP 4BD6C0CB |
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