Date: Mon, 03 Apr 1995 23:47:00 -0700 From: David Greenman <davidg@Root.COM> To: Terry Lee <teren@lyria.stanford.edu> Cc: Luigi Rizzo <luigi@labinfo.iet.unipi.it>, hackers@FreeBSD.org Subject: Re: NE2000 Plus performance Message-ID: <199504040647.XAA03106@corbin.Root.COM> In-Reply-To: Your message of "Mon, 03 Apr 95 23:32:49 PDT." <Pine.BSF.3.91.950403231241.14028C-100000@lyria.stanford.edu>
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>> SMC cards have shared memory that can be read and written at 4MB/sec. The >> NE2000 style cards (using programmed I/O) transfer bytes at about 1.7MB/sec. >> Thus when trying to do 1100KB/sec, the SMC cards take 25% of the CPU to >> read/write the packet and the NE2000 cards take more than 60% of the CPU. > >I'm confused now. So the ed driver DOES support shared memory for SMC >cards, but NOT for NE2000plus? Meaning an SMC card will out perform a >NE2000 card by a LOT! You're not confused at all - this is exactly correct. >I believe the original post was about a clone. I believe the original >NE2000"plus" spec comes from National Semiconductor's NE2000plus card. >According to the manual the default configuration is "programmed I/O" and >it has a higher performance mode called "shared RAM". Shared RAM mode can be >configured to use upper memory or extended memory. You can choose upper >memory of C000:0h, C400:0h,...DC00:0h or extended memory of >E0000:0h, E2000:0h,...FE000:0h. Is it possible that this is just the >same as the SMC spec and if I configure the card to shared memory mode, >the ed driver will just think it's an SMC card and do it's thing? It won't work. The ed driver supports (for example) the 3c503 and SMC cards shared memory, but both have completely different setup/initialization methods. The NE2000+ is another animal entirely. -DG
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