Date: Fri, 7 Mar 2003 09:16:16 -0800 (PST) From: Doug Ambrisko <ambrisko@ambrisko.com> To: Wes Peters <wes@softweyr.com> Cc: Paulo Roberto <nirv199@yahoo.com>, Bram Van Dam <gandalfbram@pandora.be>, freebsd-hackers@FreeBSD.ORG Subject: Re: Realtek Message-ID: <200303071716.h27HGHtg001578@www.ambrisko.com> In-Reply-To: <200303062136.44471.wes@softweyr.com>
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Wes Peters writes: | On Thursday 06 March 2003 15:02, Paulo Roberto wrote: | > --- Bram Van Dam <gandalfbram@pandora.be> wrote: | > > cheap they are they do their job fairly well. If performance isn't | > > an issue then go for it. | > | > I couldn't agree more. If you are just staying in 55 mph, you don't | > need a Ferrari. | | It's not a ford vs. ferrari problem, it's that the ford only has first | gear, so you're doing 45 mph at redline and in grave danger of blowing | the heads off continuously. | | The problem with the RealTek chipset is that the packets have to be | aligned on some completely stupid boundary in memory (32 bytes if memory | serves). The driver code ends up copying the packet data to a tempory | buffer before sending it for almost every outgoing packet, which is just | totally stupid. [snip] | JUST SAY NO. Actually, test and the pick the fastest tends to be better. Since D-Link dropped their good 4-port card for a broken one which they discontinued we had to scramble for a solution. Our test bed was a basically a "server" machine tied to a "router/bridge" like thing with 4 clients. We'd run tests all to the server, all to the clients and everything at once. This illustrated the HW issue with the new D-Link 4 port card since none of their "supported" drivers and OSes could get over 20Mbs. We had 100FDX links to each client and a Gig link to the server. FreeBSD could peak to 40Mbs if I recall right and we were told FreeBSD must be broken even though it was faster then their supported OSes (Windows < 1Mbs)! To be honest I did fix a bunch of bugs in the FreeBSD driver. Using this framework we had a bridge riser card that we could plug 4 various PCI ethernet cards. We tested the dc(4), fxp(4), rl(4), sis(4) cards of various types and with our motherboard and CPU the rl(4) 8139C chips where the fastest via netperf with a significant margin. I went into the test biased against Realtek but couldn't justify not using them after testing. Now we are using the 8100L chip so we have a pretty simple design. So I'd say given a sufficiently fast CPU and memory the Realteks work pretty darn good. The speed win could be do to a slightly better bus interface. That was the problem with the newer D-Link 4 port card in that during RX the chip would take over the PCI bus for a loooong time. A sufficiently fast CPU in our case is 700Mhz Celeron which is a lot different then pushing 100Mbs with a P5 133Mhz. Our bigger issue is bus performance on a 32bit/33Mhz bus with 3, 4-port cards. To date we haven't had any trouble with them and we've shipped a bunch. Doug A. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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