From owner-freebsd-hackers Sat Dec 1 4: 0:39 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from cu518.adelaide.adsl.on.net (cu518.adelaide.adsl.on.net [150.101.236.10]) by hub.freebsd.org (Postfix) with ESMTP id 6C6E937B405 for ; Sat, 1 Dec 2001 04:00:35 -0800 (PST) Received: from ns.aus.com (laptop.ns.aus.com [10.0.2.6]) by cu518.adelaide.adsl.on.net (8.11.0/8.11.0) with ESMTP id fB1E88708900; Sun, 2 Dec 2001 00:38:08 +1030 Message-ID: <3C08CF9D.2030109@ns.aus.com> Date: Sat, 01 Dec 2001 23:09:57 +1030 From: Richard Sharpe Reply-To: rsharpe@ns.aus.com User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.4) Gecko/20010917 X-Accept-Language: en-us MIME-Version: 1.0 To: Matthew Dillon Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Found the problem, w/patch (was Re: FreeBSD performing worse than Linux?) References: <20011128153817.T61580@monorchid.lemis.com> <15364.38174.938500.946169@caddis.yogotech.com> <20011128104629.A43642@walton.maths.tcd.ie> <5.1.0.14.1.20011130181236.00a80160@postamt1.charite.de> <200111302047.fAUKlT811090@apollo.backplane.com> <200111302130.fAULUU324648@apollo.backplane.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Matthew Dillon wrote: > Index: tcp_output.c > =================================================================== > RCS file: /home/ncvs/src/sys/netinet/tcp_output.c,v > retrieving revision 1.39.2.10 > diff -u -r1.39.2.10 tcp_output.c > --- tcp_output.c 2001/07/07 04:30:38 1.39.2.10 > +++ tcp_output.c 2001/11/30 21:18:10 > @@ -912,7 +912,14 @@ > tp->t_flags &= ~TF_ACKNOW; > if (tcp_delack_enabled) > callout_stop(tp->tt_delack); > +#if 0 > + /* > + * This completely breaks TCP if newreno is turned on > + */ > if (sendalot && (!tcp_do_newreno || --maxburst)) > + goto again; > +#endif > + if (sendalot) > goto again; > return (0); > } > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message OK, I have applied this patch, and FreeBSD 4.4-STABLE now seems to behave approximately the same as Linux. There are no extra ACKs, and FreeBSD now coalesces pairs of ACKs. However, performance for one client is still at 25Mb/s with the tbench run, while Linux provides around 68Mb/s. So, it is back to staring at traces. Perhaps I will get a full trace now. -- Richard Sharpe, rsharpe@ns.aus.com, LPIC-1 www.samba.org, www.ethereal.com, SAMS Teach Yourself Samba in 24 Hours, Special Edition, Using Samba To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message