From owner-freebsd-hackers Wed Aug 4 20:30:43 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from metriclient-1.uoregon.edu (metriclient-1.uoregon.edu [128.223.172.1]) by hub.freebsd.org (Postfix) with ESMTP id CB1DE14C45 for ; Wed, 4 Aug 1999 20:30:32 -0700 (PDT) (envelope-from gurney_j@efn.org) Received: (from jmg@localhost) by metriclient-1.uoregon.edu (8.9.1/8.8.7) id UAA20251; Wed, 4 Aug 1999 20:29:32 -0700 (PDT) Message-ID: <19990804202932.50575@hydrogen.fircrest.net> Date: Wed, 4 Aug 1999 20:29:32 -0700 From: John-Mark Gurney To: Dag-Erling Smorgrav Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Results of investigating optimizing calloc()... References: <001e01bedde3$d1af64c0$291c453f@kbyanc.alcnet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.69 In-Reply-To: ; from Dag-Erling Smorgrav on Wed, Aug 04, 1999 at 01:20:59PM +0200 Reply-To: John-Mark Gurney Organization: Cu Networking X-Operating-System: FreeBSD 3.0-RELEASE i386 X-PGP-Fingerprint: B7 EC EF F8 AE ED A7 31 96 7A 22 B3 D8 56 36 F4 X-Files: The truth is out there X-URL: http://resnet.uoregon.edu/~gurney_j/ Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Dag-Erling Smorgrav scribbled this message on Aug 4: > "Kelly Yancey" 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