From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757139AbYJJJBc (ORCPT ); Fri, 10 Oct 2008 05:01:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752876AbYJJJBT (ORCPT ); Fri, 10 Oct 2008 05:01:19 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:34087 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752970AbYJJJBS (ORCPT ); Fri, 10 Oct 2008 05:01:18 -0400 Date: Fri, 10 Oct 2008 11:01:00 +0200 From: Ingo Molnar To: Cyrill Gorcunov Cc: "Pallipadi, Venkatesh" , Thomas Gleixner , "H. Peter Anvin" , linux-kernel Subject: Re: [PATCH] Typo in x86 apic.c with DIVISOR setup Message-ID: <20081010090100.GC319@elte.hu> References: <20081010002203.GA23238@linux-os.sc.intel.com> <7E82351C108FA840AB1866AC776AEC463782339F@orsmsx505.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00,DNS_FROM_SECURITYSAGE autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] 0.0 DNS_FROM_SECURITYSAGE RBL: Envelope sender in blackholes.securitysage.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Cyrill Gorcunov wrote: > Ah, it was CONFG who is guilty :) This is true indeed, thanks! yeah. > But here is not the same > > apic_write(APIC_TDCR, > (tmp_value & ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE)) | > - APIC_TDR_DIV_16); > + APIC_TDR_DIV); > > On x86_64 it will be 1 now but we've used 16 for a long time in > purpose to slowdown processor's bus CLKs from APIC point of view. So I > don't think it's good idea to change it now. If we start using divisor > 1 today -- it would work for some time 'till processor bus raised to > the some speed when we'll get counter underflow before calibration > finished. > > So could you please split the patch into two: > 1) Plain CONFG typo fix (which is completely Ack'ed) > 2) APIC divisor patch (which I'm not sure if we've to touch) okay, since we typoed that CONFG thing (sidenote: we really need a .config flag that will start a grep that fails the build if there's a non-existent CONFIG option anywhere in the tree), we basically tested the divisor of 16 on a wide range of boxes. So .. how about just standardizing on the divisor of 16 on both 32-bit and 64-bit? Ingo