From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756043AbYCKLmS (ORCPT ); Tue, 11 Mar 2008 07:42:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753143AbYCKLmJ (ORCPT ); Tue, 11 Mar 2008 07:42:09 -0400 Received: from www.tglx.de ([62.245.132.106]:33795 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753051AbYCKLmI (ORCPT ); Tue, 11 Mar 2008 07:42:08 -0400 Date: Tue, 11 Mar 2008 12:41:13 +0100 (CET) From: Thomas Gleixner To: Andi Kleen cc: Ingo Molnar , linux-kernel@vger.kernel.org, akpm@osdl.org Subject: Re: [PATCH REPOST for 2.6.25] Use an own random generator for pageattr-test.c In-Reply-To: <20080311104531.GB18917@one.firstfloor.org> Message-ID: References: <20080311013014.GA28682@basil.nowhere.org> <20080311104531.GB18917@one.firstfloor.org> User-Agent: Alpine 1.00 (LFD 882 2007-12-20) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 11 Mar 2008, Andi Kleen wrote: > On Tue, Mar 11, 2008 at 09:25:21AM +0100, Thomas Gleixner wrote: > > On Tue, 11 Mar 2008, Andi Kleen wrote: > > > Use an own random generator for pageattr-test.c > > > > > > [Repost. Please ack/nack. This is a bug fix and imho a .25 late merge > > > candidate because it fixes a subtle bug] > > > > Care to point out which "subtle bug" is fixed ? > > > > You replace a random generator by another to get repeateable > > sequences. The non repeatability of the cpa test patterns is hardly a > > "subtle bug". > > The subtle bug(s) are first that it is not repeatable (it really should), As I said before. It's hardly a bug. In fact it is questionable whether fully reproducible test patterns are desired. > then that it only initializes the CPU where the code first runs > (since srandom32 is per CPU) and later might change CPUs and then that it > adds totally unnecessary state bits to CPU #0 (or whatever runs first). Can you please elaborate why changing the seed of the random generator is a bug ? Networking reseeds the random generator itself, so what ? Thanks, tglx