Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261882AbUJZBZt (ORCPT ); Mon, 25 Oct 2004 21:25:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262034AbUJZBWI (ORCPT ); Mon, 25 Oct 2004 21:22:08 -0400 Received: from zeus.kernel.org ([204.152.189.113]:4051 "EHLO zeus.kernel.org") by vger.kernel.org with ESMTP id S261893AbUJZBSs (ORCPT ); Mon, 25 Oct 2004 21:18:48 -0400 Message-ID: <417D8846.3090308@mvista.com> Date: Mon, 25 Oct 2004 16:12:06 -0700 From: George Anzinger Reply-To: george@mvista.com Organization: MontaVista Software User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4.2) Gecko/20040308 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Chris Friesen 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> In-Reply-To: <41783AE7.8040705@nortelnetworks.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: 1296 Lines: 29 Chris Friesen wrote: > George Anzinger wrote: > >> Well, that is part of the accounting overhead the increases with >> context switch rate. You also need to include the time it takes to >> figure out which of the time limits is closes (run time limit, profile >> time, slice time, etc). Then, you also need to remove the timer when >> switching away. No, it is not a lot, but it is way more than the >> nothing we do when we can turn it all over to the periodic tick. The >> choice is load sensitive overhead vs flat overhead. > > > 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. -- George Anzinger george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ - 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/