Date: Fri, 30 Nov 2001 14:43:15 -0700 From: Nate Williams <nate@yogotech.com> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: Alexander Haderer <alexander.haderer@charite.de>, freebsd-hackers@FreeBSD.ORG Subject: Re: Found the problem, w/patch (was Re: FreeBSD performing worse than Linux?) Message-ID: <15367.64883.390696.863120@caddis.yogotech.com> In-Reply-To: <200111302130.fAULUU324648@apollo.backplane.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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> I believe I have found the problem. The transmit side has a > maximum burst count imposed by newreno. As far as I can tell, if > this maxburst is hit (it defaults to 4 packets), the transmitter > just stops - presumably until it receives an ack. Note, my experiences (and John Capos) are showing degraded performance when *NOT* on a LAN segment. In other words, when packet loss enters the mix, performance tends to fall off rather quickly. This is with or without newreno (which should theoretically help with packet loss). John claims that disabling delayed_ack doesn't seem to affect his performance, and I've not been able to verify if delayed_ack helps/hurts in my situation, since the testers have been pressed for time so I can't get them to iterate through the different settings. I do however have some packet dumps, although I'm not sure they will tell anything. :( Nate To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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