From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263352AbTJUVMK (ORCPT ); Tue, 21 Oct 2003 17:12:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263367AbTJUVMJ (ORCPT ); Tue, 21 Oct 2003 17:12:09 -0400 Received: from hermine.idb.hist.no ([158.38.50.15]:5138 "HELO hermine.idb.hist.no") by vger.kernel.org with SMTP id S263352AbTJUVMF (ORCPT ); Tue, 21 Oct 2003 17:12:05 -0400 Date: Tue, 21 Oct 2003 23:21:36 +0200 To: bill davidsen Cc: linux-kernel@vger.kernel.org Subject: Re: [RFC] frandom - fast random generator module Message-ID: <20031021212136.GA15043@hh.idb.hist.no> References: <3F8E552B.3010507@users.sf.net> <3F8E58A9.20005@cyberone.com.au> <3F8E70E0.7070000@users.sf.net> <3F8E8101.70009@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.4i From: Helge Hafting Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 21, 2003 at 07:55:32PM +0000, bill davidsen wrote: > Your argument is correct, but this is data generation rather than > analysis. In doing simulation it's desirable to ensure that multiple > instances of a program don't use the same numbers. > > For instance, simulating user load against a server; I want the > simulation of human thinking time to be a number in the range n..m and > not to be the same for all threads. Sure I can get around that, and do, > but I wouldn't mind having a simple source of random bytes which was > quality PRNG and unique. Each thread use the same userspace pseudo-random generator (faster than any kernel implementation as you avoid the syscalls) and each initialize by a single read from urandom, so they get different series of numbers. Helge Hafting