From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263185AbTJPUo0 (ORCPT ); Thu, 16 Oct 2003 16:44:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263184AbTJPUng (ORCPT ); Thu, 16 Oct 2003 16:43:36 -0400 Received: from h68-147-142-75.cg.shawcable.net ([68.147.142.75]:24311 "EHLO schatzie.adilger.int") by vger.kernel.org with ESMTP id S263173AbTJPUnZ (ORCPT ); Thu, 16 Oct 2003 16:43:25 -0400 Date: Thu, 16 Oct 2003 14:42:05 -0600 From: Andreas Dilger To: Eli Billauer Cc: linux-kernel@vger.kernel.org, David Mosberger-Tang Subject: Re: [RFC] frandom - fast random generator module Message-ID: <20031016144205.I7000@schatzie.adilger.int> Mail-Followup-To: Eli Billauer , linux-kernel@vger.kernel.org, David Mosberger-Tang References: <3F8EF17A.2040502@users.sf.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <3F8EF17A.2040502@users.sf.net>; from eli_billauer@users.sourceforge.net on Thu, Oct 16, 2003 at 09:28:58PM +0200 X-GPG-Key: 1024D/0D35BED6 X-GPG-Fingerprint: 7A37 5D79 BF1B CECA D44F 8A29 A488 39F5 0D35 BED6 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Oct 16, 2003 21:28 +0200, Eli Billauer wrote: > Allow me to supply a couple facts about frandom: > > * It's not a "crappy" RNG. Its RC4 origins and the fact, that it has > passed tests indicate the opposite. A fast RNG doesn't necessarily mean > a bad one. I doubt if any test will tell the difference between frandom > and any other good RNG. You're most welcome to try. The "crappy RNG" being referred to is just some code we implemented to give us somewhat unique numbers instead of sucking CPU. > * Frandom is written completely in C. On an i686, gcc compiles the > critical part to 26 assembly instructions per byte, and I doubt if any > hand assembly would help significantly. The algorithms is clean and > simple, and the compiler performs well with it. This is still more expensive than a hw RNG (which will be about 1 ins per 4 bytes), so it would be nice to make this arch-specific if possible (runtime and compile time). Cheers, Andreas -- Andreas Dilger http://sourceforge.net/projects/ext2resize/ http://www-mddsp.enel.ucalgary.ca/People/adilger/