Date: Fri, 30 Nov 2007 10:03:07 +0100 From: Kris Kennaway <kris@FreeBSD.org> To: Jack Vogel <jfvogel@gmail.com> Cc: Vitezslav Novy <vnovy@vnovy.net>, freebsd-stable@freebsd.org Subject: Re: 7.0 BETA3 - slow TCP upload (TSO related?) Message-ID: <474FD1CB.3020601@FreeBSD.org> In-Reply-To: <2a41acea0711300016w1aa144fel1641b3dbf075e043@mail.gmail.com> References: <474FB9E5.9090208@vnovy.net> <2a41acea0711300016w1aa144fel1641b3dbf075e043@mail.gmail.com>
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Jack Vogel wrote: > On Nov 29, 2007 11:21 PM, Vitezslav Novy <vnovy@vnovy.net> wrote: >> Hello, >> >> my configuration is >> >> kernel GENERIC >> >> em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 >> options=18b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWCSUM,TSO4> >> ether 00:19:d1:0f:1c:18 >> inet 86.49.14.16 netmask 0xffffff00 broadcast 86.49.14.255 >> media: Ethernet autoselect (100baseTX <full-duplex>) >> status: active >> >> and standard "open" ipfw firewall and >> natd -u -s -m -d -dynamic -n em0 >> >> I experience very slow TCP upload from this host - cca 50kbps. >> I have some debug prints in kernel (mostly in ip_output and ipfw log) >> and I see: >> >> 1/ outgoing packet appears in ip_output with ip_len 2924 and >> m->pkthdr.csum_flags=1 >> 2/ is diverted by firewall >> 3/ Packet appears immediately again in ip_output with ip_len 2924 and >> m->pkthdr.csum_flags=1 >> 4/ Packet is accepted by firewall and dropped by ip_output with error 40 >> EMSGSIZE >> 5/ After cca 0.4s (tcp retransmit timeout?) new packet appears in >> ip_output with ip_len 1488 and m->pkthdr.csum_flags=1 >> 6/ is successfully diverted and accepted by ipfw and sent to wire. >> 7/ after tcp ack is received new packet appears in ip_output with ip_len >> 2924 and everything repeats >> >> >> Packets are not changed by natd, beacause have src address of em0. >> nat >> >> >> Upload has normal speed (512kbps) if >> I unset TSO on interface OR set net.inet.tcp.tso=0 OR (strange thing) >> delete ipfw divert rule >> >> If necessary I will collect and send more info. > > TSO is silly at 100Mb, turn it off :) When this was reported before I asked why does the driver allow it, if it is "silly" and causes so many problems? Why not just disable it by default if the link is 100Mb? Kris
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