Date: Sat, 17 Nov 2007 18:23:29 -0500 (EST) From: Mike Andrews <mandrews@bit0.com> To: Kip Macy <kip.macy@gmail.com> Cc: Denis Shaposhnikov <dsh@vlink.ru>, Mike Silbersack <silby@freebsd.org>, Andre Oppermann <andre@freebsd.org>, freebsd-current@freebsd.org Subject: Re: bizarre em + TSO + MSS issue in RELENG_7 Message-ID: <20071117182232.T59492@mindcrime.int.bit0.com> In-Reply-To: <b1fa29170711171519r65473426s1b9f3d9666ff6a92@mail.gmail.com> References: <20071117003504.R31357@mindcrime.int.bit0.com> <20071117213316.499be43b@vlink.ru> <b1fa29170711171308x62a6371dnbb939748c5c59ae2@mail.gmail.com> <20071117170537.F59492@mindcrime.int.bit0.com> <b1fa29170711171519r65473426s1b9f3d9666ff6a92@mail.gmail.com>
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On Sat, 17 Nov 2007, Kip Macy wrote: > On Nov 17, 2007 2:33 PM, Mike Andrews <mandrews@bit0.com> wrote: >> On Sat, 17 Nov 2007, Kip Macy wrote: >> >>> On Nov 17, 2007 10:33 AM, Denis Shaposhnikov <dsh@vlink.ru> wrote: >>>> On Sat, 17 Nov 2007 00:42:54 -0500 (EST) >>>> Mike Andrews <mandrews@bit0.com> wrote: >>>> >>>>> Has anyone run into problems with MSS not being respected when using >>>>> TSO, specifically on em cards? >>>> >>>> Yes, I wrote about this problem on the beginning of 2007, see >>>> >>>> http://tinyurl.com/3e5ak5 >>>> >>> >>> if_em.c:3502 >>> /* >>> * Payload size per packet w/o any headers. >>> * Length of all headers up to payload. >>> */ >>> TXD->tcp_seg_setup.fields.mss = htole16(mp->m_pkthdr.tso_segsz); >>> TXD->tcp_seg_setup.fields.hdr_len = hdr_len; >>> >>> >>> Please print out the value of tso_segsz here. It appears to be being >>> set correctly. The only thing I can think of is that t_maxopd is not >>> correct. As tso_segsz is correct here: >> >> >> It repeatedly prints 1368 during a 1 meg file transfer over a connection >> with a 1380 MSS. Any other printf's I can add? I'm working on a web page >> with tcpdump / firewall log output illustrating the issue... > > Mike - > Denis' tcpdump output doesn't show oversized segments, something else > appears to be happening there. Can you post your tcpdump output > somewhere? URL sent off-list.
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