Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263195AbTFJPa2 (ORCPT ); Tue, 10 Jun 2003 11:30:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263245AbTFJP2X (ORCPT ); Tue, 10 Jun 2003 11:28:23 -0400 Received: from gateway-1237.mvista.com ([12.44.186.158]:34040 "EHLO av.mvista.com") by vger.kernel.org with ESMTP id S263131AbTFJP1k (ORCPT ); Tue, 10 Jun 2003 11:27:40 -0400 Message-ID: <3EE5FBE8.7020900@mvista.com> Date: Tue, 10 Jun 2003 08:40:24 -0700 From: george anzinger 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: Riley Williams CC: Andrew Morton , linux-kernel@vger.kernel.org, Eric Piel Subject: Re: [PATCH] More time clean up stuff. References: In-Reply-To: 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: 1758 Lines: 48 Riley Williams wrote: > Hi George. > > I'm ignoring the rest of this - it makes sense to me, but I'm > no expert in it. However, your last point is one I can comment > about as I've dealt with it professionally many times. > > > clock_nanosleep is changed to round up to the next jiffie to > > cover starting between jiffies. > > Isn't this a case of replacing one error with another, where > one of the two errors is unavoidable? > > 1. In the old case, the sleep will on average be half a jiffie > LESS than the requested period. > > 2. In the new case, the sleep will on average be half a jiffie > MORE than the requested period. > > One or the other is unavoidable if a jiffie is the basic unit > of time resolution of the system. However, the error is totally > meaningless if we are asking to sleep for more than 15 jiffies. I had a hard time justifiying this also. I would really like to have better resolution. As to which choice to make, the standard is VERY clear here: No timer or sleep shall complete BEFORE its time. > > Best wishes from Riley. > --- > * Nothing as pretty as a smile, nothing as ugly as a frown. > > --- > Outgoing mail is certified Virus Free. > Checked by AVG anti-virus system (http://www.grisoft.com). > Version: 6.0.488 / Virus Database: 287 - Release Date: 5-Jun-2003 > > -- 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 - 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/