Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264147AbTEaGGR (ORCPT ); Sat, 31 May 2003 02:06:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264150AbTEaGGR (ORCPT ); Sat, 31 May 2003 02:06:17 -0400 Received: from pizda.ninka.net ([216.101.162.242]:1973 "EHLO pizda.ninka.net") by vger.kernel.org with ESMTP id S264147AbTEaGGR (ORCPT ); Sat, 31 May 2003 02:06:17 -0400 Date: Fri, 30 May 2003 23:18:13 -0700 (PDT) Message-Id: <20030530.231813.59666274.davem@redhat.com> To: scrosby@cs.rice.edu Cc: alexander.riesen@synopsys.COM, linux-kernel@vger.kernel.org Subject: Re: Algoritmic Complexity Attacks and 2.4.20 the dcache code From: "David S. Miller" In-Reply-To: References: <20030530085901.GB11885@Synopsys.COM> <20030530.020040.52897577.davem@redhat.com> X-FalunGong: Information control. X-Mailer: Mew version 2.1 on Emacs 21.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Scott A Crosby Date: 30 May 2003 10:05:51 -0500 On Fri, 30 May 2003 02:00:40 -0700 (PDT), "David S. Miller" writes: > Indeed, I'd missed this. GCC will emit the constant multiply > expansion unless the multiply cost is set VERY low. It may still be a win. This does a bit under a dozen instructions per byte. However, jenkin's does many bytes at a time. It turns out to not be the case at all. There is too much work involved in the main loop just maintaining the 3-word + curbyte state. It needs to be optimized a bit. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/