Date: Sat, 01 Dec 2001 23:09:57 +1030 From: Richard Sharpe <sharpe@ns.aus.com> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Found the problem, w/patch (was Re: FreeBSD performing worse than Linux?) Message-ID: <3C08CF9D.2030109@ns.aus.com> 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>
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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
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