Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932276AbVIEHoc (ORCPT ); Mon, 5 Sep 2005 03:44:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932278AbVIEHoc (ORCPT ); Mon, 5 Sep 2005 03:44:32 -0400 Received: from caramon.arm.linux.org.uk ([212.18.232.186]:22543 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id S932276AbVIEHoc (ORCPT ); Mon, 5 Sep 2005 03:44:32 -0400 Date: Mon, 5 Sep 2005 08:44:25 +0100 From: Russell King To: Srivatsa Vaddagiri Cc: Nishanth Aravamudan , Con Kolivas , linux-kernel@vger.kernel.org, akpm@osdl.org, ck list Subject: Re: [PATCH 1/3] dynticks - implement no idle hz for x86 Message-ID: <20050905084425.B24051@flint.arm.linux.org.uk> Mail-Followup-To: Srivatsa Vaddagiri , Nishanth Aravamudan , Con Kolivas , linux-kernel@vger.kernel.org, akpm@osdl.org, ck list References: <20050831165843.GA4974@in.ibm.com> <200509031801.09069.kernel@kolivas.org> <20050903090650.B26998@flint.arm.linux.org.uk> <200509031814.49666.kernel@kolivas.org> <20050904201054.GA4495@us.ibm.com> <20050905070053.GA7329@in.ibm.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: <20050905070053.GA7329@in.ibm.com>; from vatsa@in.ibm.com on Mon, Sep 05, 2005 at 12:30:53PM +0530 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1575 Lines: 31 On Mon, Sep 05, 2005 at 12:30:53PM +0530, Srivatsa Vaddagiri wrote: > On Sun, Sep 04, 2005 at 01:10:54PM -0700, Nishanth Aravamudan wrote: > > First of all, and maybe this is just me, I think it would be good to > > make the dyn_tick_timer per-interrupt source, as opposed to each arch? > > Nish, may be a good idea as it may make the code more cleaner (it will > remove the 'if (cpu_has_local_apic())' kind of code that is there > currently in x86). However note that ARM currently has 'handler' member also > part of it, which is used to recover time and that has nothing to do with > interrupt source. Unless there is something like John's TOD, we still > need to recover time in a arch-dependent fashion ..Where do you > propose to have that 'handler' member? Exactly where it is. It's there because of the problem you allude to above - it's there to catch up system time. Any generic code can't answer the question "how much time has passed since we disabled the timer" without additional information. However, we could change "handler" to be a function pointer which returns the number of missed ticks instead, and then updates the kernels time and tick keeping. That would probably be more efficient. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/