Date: Sun, 03 Sep 2000 12:28:11 -0700 From: "Kevin Oberman" <oberman@es.net> To: Emmanuel Gravel <egravel@earthlink.net> Cc: freebsd-net@FreeBSD.ORG Subject: Re: Increasing network performance Message-ID: <200009031928.e83JSBU07183@ptavv.es.net> In-Reply-To: Your message of "Sat, 02 Sep 2000 21:44:17 PDT." <200009030438.VAA24762@avocet.prod.itd.earthlink.net>
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Emmanual, This performance is WAY below what you should be seeing. The card may not be the best choice, but it is not terrible, either. > When exchanging files between my FreeBSD box and others on the > network, and no Internet traffic, at maximum I've seen ~ 250 KB/s > (not quite 2 Mb/s) transfer rates. When I get Internet traffic, the transfer > rate goes way down if I also try to transfer files, and I get strange > behaviour from the network. Traffic happens in bursts, which seem > usually (but not always) disrupted by collisions, and usually there's > a fairly long pause (a few seconds) before traffic starts again. I would > think part of it has to do with the system being dual-homed, with two > 509's, but I'm sure there has to be something to do to improve performance > somehow. Does anyone know where I should look to get my box to > react a little more sanely? If there's anything else you want to know > just ask :) Collisions are seldom an issue. People get excited by the blinking light, but the cost of a collision is very low. 'netstat -i' will report both collisions and errors. Only errors should cause a significant hit on performance. (They require the CPU to get involved and are very expensive!) Collisions are a simple Ethernet flow control mechanism and re-transmission of the colliding packets is handled by the controllers with no CPU involvement other than bumping the collision counter. Are you sure that all of the Ethernet cards are running half-duplex? The symptoms you report are commonly seen when you have a full-duplex interface talking to a half-duplex unit, or, worse yet, to a hub. R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: oberman@es.net Phone: +1 510 486-8634 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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