Date: Mon, 7 Dec 1998 16:14:08 -0500 (EST) From: "Ron G. Minnich" <rminnich@Sarnoff.COM> To: hackers@FreeBSD.ORG Subject: Re: write combining memory on pci Message-ID: <Pine.SUN.3.91.981207161159.9378E-100000@terra> In-Reply-To: <366C43DD.A7DA16F4@tdx.co.uk>
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On Mon, 7 Dec 1998, Karl Pielorz wrote: > Both my P-Pro systems have this option, and AFAIK it worked as above (i.e. > 'all on' or 'all off')... Win NT survives with it on, until I try to use the > sound card, and FreeBSD, Linux & Win'95 all die within seconds with it on Hmm, that is bad news. I have some cards from a company that only run fast with write combining turned ON. However, if they crash the OS with it on, it might not be such a good deal. Guess I'll have to use the cards as a master, not a target for PIO writes. As ever, the rule with PCI: don't get the CPU involved in data transfer :-) > Which is a bit of a pitty, as I also seem to remember reading it gives a huge > performance win on writes ;-) - Maybe there is such a thing as 'too fast'... something on order of at least 2x. It would be nice to have ... ron To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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