Date: Wed, 31 Dec 2008 11:49:01 +0100 From: =?UTF-8?B?VsOhY2xhdiBIYWlzbWFu?= <v.haisman@sh.cvut.cz> Cc: stable@freebsd.org Subject: Re: TCP packet out-of-order problem Message-ID: <495B4E1D.6020902@sh.cvut.cz> In-Reply-To: <47713ee10812301206j12b35264o715976c154080a1b@mail.gmail.com> References: <47713ee10812301206j12b35264o715976c154080a1b@mail.gmail.com>
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Lin Jui-Nan Eric wrote, On 30.12.2008 21:06: > Dear listers, > > We recently found our new FreeBSD server (located in some foreign > region) has poor network performance. After doing some tcpdump and > iperf testing, we found that out-of-order TCP packets are not inserted > into queue. > > This is an 100Mbps line, and TSO is disabled. > > % uname -a > FreeBSD bsd 7.1-RC2 FreeBSD 7.1-RC2 #2: Wed Dec 31 03:12:39 CST 2008 > root@bsd:/usr/obj/usr/src/sys/KERNEL amd64 > > % iperf -c 10.1.1.250 > ------------------------------------------------------------ > Client connecting to office, TCP port 5001 > TCP window size: 3.07 MByte (default) > ------------------------------------------------------------ > [ 4] local 10.1.1.210 port 61488 connected with 10.1.1.250 port 5001 > [ ID] Interval Transfer Bandwidth > [ 4] 0.0-10.2 sec 5.74 MBytes 4.74 Mbits/sec > > 03:47:21.146397 IP 10.1.1.210.54919 > 10.1.1.250.5001: . > 159305:160753(1448) ack 1 win 1040 <nop,nop,timestamp 555928950 > 3216612488> > 03:47:21.146409 IP 10.1.1.250.5001 > 10.1.1.210.54919: . ack 160753 > win 12568 <nop,nop,timestamp 3216612488 555928950> > 03:47:21.146473 IP 10.1.1.210.54919 > 10.1.1.250.5001: . > 160753:162201(1448) ack 1 win 1040 <nop,nop,timestamp 555928950 > 3216612488> > 03:47:21.146485 IP 10.1.1.250.5001 > 10.1.1.210.54919: . ack 162201 > win 12568 <nop,nop,timestamp 3216612489 555928950> > 03:47:21.146972 IP 10.1.1.210.54919 > 10.1.1.250.5001: . > 163649:165097(1448) ack 1 win 1040 <nop,nop,timestamp 555928950 > 3216612488> > 03:47:21.146983 IP 10.1.1.250.5001 > 10.1.1.210.54919: . ack 162201 > win 12573 <nop,nop,timestamp 3216612489 555928950> > 03:47:21.146985 IP 10.1.1.210.54919 > 10.1.1.250.5001: . > 162201:163649(1448) ack 1 win 1040 <nop,nop,timestamp 555928950 > 3216612488> > 03:47:21.146996 IP 10.1.1.250.5001 > 10.1.1.210.54919: . ack 163649 > win 12568 <nop,nop,timestamp 3216612489 555928950> > 03:47:21.146998 IP 10.1.1.210.54919 > 10.1.1.250.5001: . > 165097:166545(1448) ack 1 win 1040 <nop,nop,timestamp 555928950 > 3216612488> > 03:47:21.147006 IP 10.1.1.250.5001 > 10.1.1.210.54919: . ack 163649 > win 12573 <nop,nop,timestamp 3216612489 555928950> > 03:47:21.147009 IP 10.1.1.210.54919 > 10.1.1.250.5001: . > 166545:167993(1448) ack 1 win 1040 <nop,nop,timestamp 555928950 > 3216612488> > 03:47:21.147017 IP 10.1.1.250.5001 > 10.1.1.210.54919: . ack 163649 > win 12573 <nop,nop,timestamp 3216612489 555928950> > 03:47:21.147019 IP 10.1.1.210.54919 > 10.1.1.250.5001: . > 167993:169441(1448) ack 1 win 1040 <nop,nop,timestamp 555928950 > 3216612488> > > * You can see "ack 163649" repeating, but the packet is transmitted > before 163649:165097. > > % cat /etc/sysctl.conf > # $FreeBSD: src/etc/sysctl.conf,v 1.8 2003/03/13 18:43:50 mux Exp $ > # > # This file is read when going to multi-user and its contents piped thru > # ``sysctl'' to adjust kernel values. ``man 5 sysctl.conf'' for details. > # > > # Uncomment this to prevent users from seeing information about processes that > # are being run under another UID. > #security.bsd.see_other_uids=0 > debug.bootverbose=1 > kern.ipc.somaxconn=8192 > kern.maxfiles=65536 > kern.maxfilesperproc=32768 > kern.maxprocperuid=65536 > net.inet.ip.fastforwarding=1 > net.inet.tcp.delayed_ack=0 > vm.pmap.shpgperproc=2000 > kern.ipc.maxsockbuf=8388608 > net.inet.tcp.sendspace=3217968 > net.inet.tcp.recvspace=3217968 > > Is our configuration wrong? Or it is an known bug? I have searched > stable & net list, but found no similar discussion. > Thank you all in advance! Do you have net.inet.tcp.sack.enable=1? -- VH
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