From owner-freebsd-current Sun Aug 13 21: 9:20 2000 Delivered-To: freebsd-current@freebsd.org Received: from alcanet.com.au (mail.alcanet.com.au [203.62.196.10]) by hub.freebsd.org (Postfix) with SMTP id 67B4537B9E4 for ; Sun, 13 Aug 2000 21:09:11 -0700 (PDT) (envelope-from jeremyp@gsmx07.alcatel.com.au) Received: by border.alcanet.com.au id <115211>; Mon, 14 Aug 2000 14:09:05 +1000 Content-return: prohibited Date: Mon, 14 Aug 2000 14:09:01 +1000 From: Peter Jeremy Subject: Re: Slow ssh throughput with -current In-reply-to: <00Aug10.153604est.115242@border.alcanet.com.au>; from peter.jeremy@alcatel.com.au on Thu, Aug 10, 2000 at 03:36:01PM +1000 To: current@FreeBSD.ORG Mail-followup-to: current@FreeBSD.ORG Message-Id: <00Aug14.140905est.115211@border.alcanet.com.au> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii Content-disposition: inline User-Agent: Mutt/1.2.4i References: <00Aug10.153604est.115242@border.alcanet.com.au> Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 2000-Aug-10 15:36:01 +1000, Peter Jeremy wrote: >I just noticed a really peculiar network slowdown with -current from >about a week ago. The machine has two NICs - an old 16-bit SMC card >(ed0) running 10baseT and a PCI SMC card (tx0) running 100baseTX full >duplex. > >When I scp (either ssh-1.2.27 or OpenSSH) to a remote machine via ed0, >I get a throughput of ~8KB/sec. When I go via tx0, I get ~3MB/sec >(CPU limited). If I use ftp via ed0, I get wire speed (just over >1MB/sec). Having done some more tests, and a bit more digging, I've found the culprit is net.inet.tcp.newreno. When set to 1 (the default), ssh (but not FTP) connections to hosts not on the same subnet (as determined by in_localaddr()) have an effective window size of 1 MSS. Unfortunately, I can't see any obvious reason why initialising maxburst to 4 results in only a single packet on each call to tcp_output() for ssh connections. Peter To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message