From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261870AbVGOIm0 (ORCPT ); Fri, 15 Jul 2005 04:42:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263243AbVGOIm0 (ORCPT ); Fri, 15 Jul 2005 04:42:26 -0400 Received: from caramon.arm.linux.org.uk ([212.18.232.186]:64014 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id S261870AbVGOImY (ORCPT ); Fri, 15 Jul 2005 04:42:24 -0400 Date: Fri, 15 Jul 2005 09:41:57 +0100 From: Russell King To: Linus Torvalds Cc: Jesper Juhl , Lee Revell , Chris Wedgwood , Andrew Morton , "Brown, Len" , dtor_core@ameritech.net, vojtech@suse.cz, david.lang@digitalinsight.com, davidsen@tmr.com, kernel@kolivas.org, linux-kernel@vger.kernel.org, mbligh@mbligh.org, diegocg@gmail.com, azarah@nosferatu.za.org, christoph@lameter.com Subject: Re: [PATCH] i386: Selectable Frequency of the Timer Interrupt Message-ID: <20050715094157.C25428@flint.arm.linux.org.uk> Mail-Followup-To: Linus Torvalds , Jesper Juhl , Lee Revell , Chris Wedgwood , Andrew Morton , "Brown, Len" , dtor_core@ameritech.net, vojtech@suse.cz, david.lang@digitalinsight.com, davidsen@tmr.com, kernel@kolivas.org, linux-kernel@vger.kernel.org, mbligh@mbligh.org, diegocg@gmail.com, azarah@nosferatu.za.org, christoph@lameter.com References: <1121282025.4435.70.camel@mindpipe> <1121286258.4435.98.camel@mindpipe> <20050713134857.354e697c.akpm@osdl.org> <20050713211650.GA12127@taniwha.stupidest.org> <9a874849050714170465c979c3@mail.gmail.com> <1121386505.4535.98.camel@mindpipe> <9a874849050714171767b85ced@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: ; from torvalds@osdl.org on Thu, Jul 14, 2005 at 05:42:15PM -0700 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 14, 2005 at 05:42:15PM -0700, Linus Torvalds wrote: > So this is why I so strongly argue that we should have a constant HZ, but > a dynamic _increment_ of "jiffies". Nobody (obviously) depends on jiffies > being constant, so it's ok to increment jiffies by pretty much any value. I agree. Isn't this exactly what HZ=1000 with VST achieves? We know this works already... > But I really wouldn't be surprised if the bogomips calibration loop was > really the only thing that needed some small tweaking for increments of > other than one. Having run VST on ARM, VST must be disabled while the bogomips calibrations have completed - I suspect VST requires some sort of enable/disable counted system like we do for interrupts and the hlt thing, so that the hotplug CPU code can do it's bogomips calibration appropriately. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core