From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (from majordomo@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id AAA19180; Thu, 7 Jun 2001 00:27:41 +0200 (MET DST) X-Authentication-Warning: pauillac.inria.fr: majordomo set sender to owner-caml-list@pauillac.inria.fr using -f Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id AAA18789 for ; Thu, 7 Jun 2001 00:27:40 +0200 (MET DST) Received: from smtp3-cm.mail.eni.net (smtp3-cm.mail.eni.net [216.133.226.136]) by concorde.inria.fr (8.11.1/8.10.0) with ESMTP id f56MRcL29089 for ; Thu, 7 Jun 2001 00:27:39 +0200 (MET DST) Received: from checkerlap.d6.com (node-d8e9cca2.powerinter.net [216.233.204.162]) by smtp3-cm.mail.eni.net (8.9.3/8.9.3) with ESMTP id PAA30055; Wed, 6 Jun 2001 15:27:34 -0700 Message-Id: <4.3.2.7.2.20010606152725.02a22310@shell16.ba.best.com> X-Sender: def6@shell16.ba.best.com X-Mailer: QUALCOMM Windows Eudora Version 4.3.2 Date: Wed, 06 Jun 2001 15:29:49 -0700 To: William Chesters , caml-list@inria.fr From: Chris Hecker Subject: Re: [Caml-list] OCaml Speed for Block Convolutions In-Reply-To: <15134.36575.982859.678763@beertje.william.bogus> References: <20010605003423.A20283@miss.wu-wien.ac.at> <002f01c0ecf9$d028a3b0$210148bf@dylan> <15131.59080.327155.47983@beertje.william.bogus> <002a01c0ed33$0b3d5de0$210148bf@dylan> <20010605003423.A20283@miss.wu-wien.ac.at> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: owner-caml-list@pauillac.inria.fr Precedence: bulk >My feeling has always been that the overhead of initialising a float >array, per element, is considerably less than the cost of one floating >point operation; so if you ever intend to actually use the array for >anything, the inefficiency is negligible. This is not true on modern processors, if I understand what you're saying. Touching memory that's not in the cache is orders of magnitude slower than flops. Even the best case, with the memory in the cache, touching memory is the same speed or slower than doing a flop on most CPUs. Chris ------------------- To unsubscribe, mail caml-list-request@inria.fr. Archives: http://caml.inria.fr