From owner-freebsd-hackers Thu Aug 5 1:50:30 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from flood.ping.uio.no (flood.ping.uio.no [129.240.78.31]) by hub.freebsd.org (Postfix) with ESMTP id 55E0B1524B for ; Thu, 5 Aug 1999 01:50:27 -0700 (PDT) (envelope-from des@flood.ping.uio.no) Received: (from des@localhost) by flood.ping.uio.no (8.9.3/8.9.1) id KAA51210; Thu, 5 Aug 1999 10:49:53 +0200 (CEST) (envelope-from des) To: Peter Jeremy Cc: hackers@FreeBSD.ORG Subject: Re: Results of investigating optimizing calloc()... References: <99Aug5.072253est.40331@border.alcanet.com.au> From: Dag-Erling Smorgrav Date: 05 Aug 1999 10:49:52 +0200 In-Reply-To: Peter Jeremy's message of "Thu, 5 Aug 1999 07:42:17 +1000" Message-ID: Lines: 16 X-Mailer: Gnus v5.5/Emacs 19.34 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Peter Jeremy writes: > Dag-Erling Smorgrav wrote: > > The idea is to keep a chunk of zeroes on disk and DMA it into memory > Have you looked at disk latencies recently? A modern CPU could zero- > fill a decent fraction of its RAM in the time taken to fetch a page of > zeroes from the platter. And if it was accessed frequently enough to > keep the zeroed page in disk cache, you've just moved the bottleneck > into that disk controller (and you've reduced the effective size of the > disk's cache by a page). It still beats the hell out of invalidating your entire L1 and L2 caches. DES -- Dag-Erling Smorgrav - des@flood.ping.uio.no To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message