Date: Wed, 4 Aug 1999 19:04:56 +0200 (CEST) From: Wilko Bulte <wilko@yedi.iaf.nl> To: des@flood.ping.uio.no (Dag-Erling Smorgrav) Cc: kbyanc@alcnet.com, freebsd-hackers@FreeBSD.ORG Subject: Re: Results of investigating optimizing calloc()... Message-ID: <199908041704.TAA00730@yedi.iaf.nl> In-Reply-To: <xzpemhjpzac.fsf@flood.ping.uio.no> from Dag-Erling Smorgrav at "Aug 4, 1999 1:20:59 pm"
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As Dag-Erling Smorgrav wrote ... > "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. Wow.. I once saw this used, ages ago on a Uniflex machine running on a Motorola 6809 cpu. They used a slightly different approach by doing dma to a non-existent piece of hardware (memory is dim here...) that resulted in zeros being read from the databus. The fact that TSC (the makers of Uniflex) did this was discovered when Uniflex was ported over to a slightly different set of hardware that used inverting databuffers ;-) Wilko -- | / o / / _ Arnhem, The Netherlands - Powered by FreeBSD - |/|/ / / /( (_) Bulte WWW : http://www.tcja.nl http://www.freebsd.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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