Date: Mon, 3 Apr 1995 23:32:49 -0700 (PDT) From: Terry Lee <teren@lyria.stanford.edu> To: David Greenman <davidg@Root.COM> Cc: Luigi Rizzo <luigi@labinfo.iet.unipi.it>, hackers@FreeBSD.org Subject: Re: NE2000 Plus performance Message-ID: <Pine.BSF.3.91.950403231241.14028C-100000@lyria.stanford.edu> In-Reply-To: <199504032246.PAA02907@corbin.Root.COM>
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On Mon, 3 Apr 1995, David Greenman wrote: > >> It's not supported. I didn't even know of the NE2000+ existence until you > >> mentioned here. > > > >Ok. A couple of questions about network ards and drivers, though: > > > >1) how much faster are memory-mapped cards wrt io-mapped ones ? Is it > > just the clock cycle per word that you save in transferring data > > with MOVSW instead of INSW, or there is more (e.g. the driver > > does more or less random access to the board, thus has to waste > > time specifying the address of the desired data quite often) ? > > 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! 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? Terry I N T E R N E T Terry Lee, Technical Director D E S I G N 745 Stanford Avenue, Palo Alto, California 94306 G R O U P 415 424 0747 voice 415 424-0751 fax http://www.mall.net terryl@cs.stanford.edu http://www.mall.net/terry
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