Date: Tue, 29 May 2007 15:51:41 +0100 (BST) From: Robert Watson <rwatson@FreeBSD.org> To: Stephen Clark <Stephen.Clark@seclark.us> Cc: freebsd-stable@freebsd.org Subject: Re: network performance 6.1 stable vs 4.9 Message-ID: <20070529154919.U2510@fledge.watson.org> In-Reply-To: <4656D0FB.5070200@seclark.us> References: <4656D0FB.5070200@seclark.us>
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On Fri, 25 May 2007, Stephen Clark wrote: > We have a network appliance that is currently based on 4.9. We are in the > process of releasing a new version based on 6.1 stable. > > In our testing using nttcp thru the appliance we see insignifant difference > in thruput between the 2 versions in a controlled environment - aproximately > 94mbs on a 100mb lan. > > We have a person that is testing the both system inhouse surfing out over > the internet on our T1 link and he complains that he is consistently seeing > the 6.1 version being much slower than the 4.9 version (on the same > hardware). He has been comparing the 6.1 system to 4.9 system for a couple > of weeks and continues to insist the 6.1 version is much slower. > > Are there any sysctl tunables that may affect performance going over the > internet with a slower link, dropped packets, etc that could cause this? > > Any ideas would be appreciated. Steve, The first thing I'd do is try a double-blind test for your testers -- don't tell them which version is running, and then compare performance complaints with/without. This would let you know if there's actually a difference. The main piece of advice I give people when working with 6.x is to consider turning on net.isr.direct, which enables direct dispatch in the network stack. With 4.x, I get lower forwarding and processing latency than 6.x unless I enable this. However, my recollection is that you don't want to turn it on on releases before 6.1, and I would really be most comfortable turning it on with 6.2 and later. In FreeBSD 7.0, net.isr.direct is the default. You might give that a try and see if it has an effect, but I'd see about getting some sort of objective testing of performance going to confirm that this isn't a subjectivity issue. Robert N M Watson Computer Laboratory University of Cambridge > > Steve > > -- > > "They that give up essential liberty to obtain temporary safety, deserve > neither liberty nor safety." (Ben Franklin) > > "The course of history shows that as a government grows, liberty decreases." > (Thomas Jefferson) > > > > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" >
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