Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S271186AbUJVDGU (ORCPT ); Thu, 21 Oct 2004 23:06:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S271057AbUJVC5A (ORCPT ); Thu, 21 Oct 2004 22:57:00 -0400 Received: from zcars04e.nortelnetworks.com ([47.129.242.56]:44472 "EHLO zcars04e.nortelnetworks.com") by vger.kernel.org with ESMTP id S271202AbUJVCur (ORCPT ); Thu, 21 Oct 2004 22:50:47 -0400 Message-ID: <41783AE7.8040705@nortelnetworks.com> Date: Thu, 21 Oct 2004 16:40:39 -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> In-Reply-To: <41782771.3060404@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: 1087 Lines: 22 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. 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/