Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262095AbUJZEVh (ORCPT ); Tue, 26 Oct 2004 00:21:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262155AbUJZESx (ORCPT ); Tue, 26 Oct 2004 00:18:53 -0400 Received: from zcars04f.nortelnetworks.com ([47.129.242.57]:41117 "EHLO zcars04f.nortelnetworks.com") by vger.kernel.org with ESMTP id S262080AbUJZBlb (ORCPT ); Mon, 25 Oct 2004 21:41:31 -0400 Message-ID: <417D918E.8030804@nortelnetworks.com> Date: Mon, 25 Oct 2004 17:51:42 -0600 X-Sybari-Space: 00000000 00000000 00000000 00000000 From: Chris Friesen User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040113 X-Accept-Language: en-us, en MIME-Version: 1.0 To: george@mvista.com CC: "Perez-Gonzalez, Inaky" , root@chaos.analogic.com, "Brown, Len" , Tim Schmielau , john stultz , lkml Subject: Re: gradual timeofday overhaul References: <41782771.3060404@mvista.com> <41783AE7.8040705@nortelnetworks.com> <417D8846.3090308@mvista.com> In-Reply-To: <417D8846.3090308@mvista.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1105 Lines: 25 George Anzinger wrote: > Chris Friesen wrote: >> It should be possible to be clever about this. Most processes don't >> use their timeslice, so if we have a previous timer running, just keep >> track of how much beyond that timer our timeslice will be. If we >> context switch before the timer expiry, well and good. If the timer >> expires, set it for what's left of our timeslice. > > > Me thinks that rather quickly devolves to a periodic tick. In the busy case, yes. But on an idle system you get tickless behaviour. It's still going to be load-sensitive, since you are doing additional work to keep track of the timer/timeout values. But it saves work if reprogramming the timer is time-consuming compared to simply reading it. On something like the ppc, it probably doesn't buy you much since the decrementer is cheap to program. Chris - 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/