Date: Thu, 26 Sep 2002 16:02:44 +0300 From: Vallo Kallaste <kalts@estpak.ee> To: David Kelly <dkelly@hiwaay.net> Cc: Cody Swanson <cswanson@pei.eastlink.ca>, freebsd-questions@FreeBSD.ORG Subject: Re: Performance issues with natd Message-ID: <20020926130244.GD2034@tiiu.internal> In-Reply-To: <20020925220803.GC17390@grumpy.dyndns.org> References: <007401c264bd$d97909e0$0401a8c0@win2000> <20020925220803.GC17390@grumpy.dyndns.org>
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On Wed, Sep 25, 2002 at 05:08:03PM -0500, David Kelly <dkelly@hiwaay.net> wrote: > One thing to try is to invert the functions of vr0 and xl0. > > Another Good Thing To Try is to read man pages and source code on the > devices you are using. This is found in /usr/src/sys/pci/if_vr.c: > > * > * The Rhine has a serious flaw in its transmit DMA mechanism: > * transmit buffers must be longword aligned. Unfortunately, > * FreeBSD doesn't guarantee that mbufs will be filled in starting > * at longword boundaries, so we have to do a buffer copy before > * transmission. > */ > > Am suggesting replacing the vr0 with something else such as another > 3c905. I use a pair of Intel 10/100's in my PIII-500 box and would have > to measure carefully to detect any thruput blockage. > > My guess as to what is happening is the additional copy required by the > vr0 interrupts the rhythm between your inside client and the outside > cable system so that data doesn't stream at full rate when passing thru > but is OK when it stops at the FreeBSD firewall/router/gateway. > > In a PII-300 system I use an onboard 3c905 and an Intel 10/100. IPFW, > NATD, DIVERT, essentially the same as you but only 64MB, and once again > the restriction is too small to notice without careful measurement. It > too is connected to a cable modem but throttled at 500kbits/sec. > > I have a spare PII but have not bothered to benchmark it ethernet to > ethernet. All that said, even old (16bit)NE2000 clone will easily sustain 800+kB/s on my old 133Mhz Pentium with CPU load 20% or so. 400kB/s versus 100kB/s throughput difference in this particular case isn't matter of 3Com vs. Via NIC, I guess. I'll suggest trying out IPFilter (ipf) and let us know of the results. -- Vallo Kallaste kalts@estpak.ee To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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