From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750931AbVHHPGo (ORCPT ); Mon, 8 Aug 2005 11:06:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750933AbVHHPGo (ORCPT ); Mon, 8 Aug 2005 11:06:44 -0400 Received: from e35.co.us.ibm.com ([32.97.110.133]:51598 "EHLO e35.co.us.ibm.com") by vger.kernel.org with ESMTP id S1750929AbVHHPGn (ORCPT ); Mon, 8 Aug 2005 11:06:43 -0400 Date: Mon, 8 Aug 2005 20:36:56 +0530 From: Srivatsa Vaddagiri To: Tony Lindgren Cc: Con Kolivas , Adrian Bunk , linux-kernel@vger.kernel.org, ck@vds.kolivas.org, tuukka.tikkanen@elektrobit.com, george@mvista.com, Andrew Morton Subject: Re: [PATCH] i386 No-Idle-Hz aka Dynamic-Ticks 5 Message-ID: <20050808150656.GA16993@in.ibm.com> Reply-To: vatsa@in.ibm.com References: <200508031559.24704.kernel@kolivas.org> <200508060239.41646.kernel@kolivas.org> <20050806174739.GU4029@stusta.de> <200508071512.22668.kernel@kolivas.org> <20050807165833.GA13918@in.ibm.com> <20050808073822.GF28070@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050808073822.GF28070@atomide.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 08, 2005 at 12:38:23AM -0700, Tony Lindgren wrote: > It should not matter when the PIT gets reprogrammed, as the system time is > not updated from PIT timer. Jiffies are calculated from a second timer, such > as ACPI PM timer or TSC. I am more worried about timer latencies and its effects. Because of this skew between when jiffy interrupt was originally supposed to happen and when it will now happen, it can lead to, for example, scheduling latencies upto 1 jiffy (for HZ=100, that could hurt some apps?) Not to mention that this will not play well with high-res-timers, but that is probably not a concern now! -- Thanks and Regards, Srivatsa Vaddagiri, Linux Technology Center, IBM Software Labs, Bangalore, INDIA - 560017