Date: Wed, 4 Aug 1999 20:29:32 -0700 From: John-Mark Gurney <gurney_j@efn.org> To: Dag-Erling Smorgrav <des@flood.ping.uio.no> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Results of investigating optimizing calloc()... Message-ID: <19990804202932.50575@hydrogen.fircrest.net> In-Reply-To: <xzpemhjpzac.fsf@flood.ping.uio.no>; from Dag-Erling Smorgrav on Wed, Aug 04, 1999 at 01:20:59PM %2B0200 References: <001e01bedde3$d1af64c0$291c453f@kbyanc.alcnet.com> <xzpemhjpzac.fsf@flood.ping.uio.no>
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Dag-Erling Smorgrav scribbled this message on Aug 4: > "Kelly Yancey" <kbyanc@alcnet.com> writes: > > [...] > > Which reminds me - has anyone thought of using DMA for zeroing pages, > to avoid cache invalidation? The idea is to keep a chunk of zeroes on > disk and DMA it into memory instead of clearing pages "manually". This > assumes your disk supports DMA, of course. has anyone looked at using two dma channels tied together to do memory copies? I haven't studied the DMA specs, but from what I know of the dma on x86 machines is that you could tie two dma channels together one to feed the other, and this would allow you to copy memory w/o using the processor... w/ dma channels, we can just make a copy of the base zero page... -- John-Mark Gurney Voice: +1 541 684 8449 Cu Networking P.O. Box 5693, 97405 "The soul contains in itself the event that shall presently befall it. The event is only the actualizing of its thought." -- Ralph Waldo Emerson To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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