From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264361AbTLPHpz (ORCPT ); Tue, 16 Dec 2003 02:45:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264364AbTLPHpz (ORCPT ); Tue, 16 Dec 2003 02:45:55 -0500 Received: from gateway-1237.mvista.com ([12.44.186.158]:19952 "EHLO av.mvista.com") by vger.kernel.org with ESMTP id S264361AbTLPHpy (ORCPT ); Tue, 16 Dec 2003 02:45:54 -0500 Message-ID: <3FDEB82C.80908@mvista.com> Date: Mon, 15 Dec 2003 23:45:48 -0800 From: George Anzinger Organization: MontaVista Software User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2) Gecko/20021202 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Jamie Lokier CC: Nick Piggin , Guillaume Foliard , linux-kernel@vger.kernel.org Subject: Re: Scheduler degradation since 2.5.66 References: <200312142048.51579.guifo@wanadoo.fr> <3FDD205A.6040807@cyberone.com.au> <3FDD35F9.7090709@cyberone.com.au> <3FDE5449.60507@mvista.com> <20031216005251.GB3364@mail.shareable.org> In-Reply-To: <20031216005251.GB3364@mail.shareable.org> 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 Jamie Lokier wrote: > George Anzinger wrote: > >>Try running the test with a requested sleep time of something less than >>0.999849 ms. All this is for the x86 which is using this time to do the >>best it can with the PIT which can only get this close to 1 ms ticks. You >>can even vary this number to see exactly where the round up actually >>happens. Ah, life in the nano world :) > > > Would it be better to program the PIT for lowest frequency that's >= 1.0ms. Possibly. I haven't attempted to analize it. I do know it would make some of the math a bear. Integers like to round down (read truncate) so... But then, what we have isn't exactly fun :) -- George Anzinger george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml