From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261332AbVHAXaE (ORCPT ); Mon, 1 Aug 2005 19:30:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261338AbVHAXaE (ORCPT ); Mon, 1 Aug 2005 19:30:04 -0400 Received: from gateway-1237.mvista.com ([12.44.186.158]:44274 "EHLO av.mvista.com") by vger.kernel.org with ESMTP id S261332AbVHAXaC (ORCPT ); Mon, 1 Aug 2005 19:30:02 -0400 Message-ID: <42EEB004.4040601@mvista.com> Date: Mon, 01 Aug 2005 16:28:04 -0700 From: George Anzinger Reply-To: george@mvista.com Organization: MontaVista Software User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.6) Gecko/20050323 Fedora/1.7.6-1.3.2 X-Accept-Language: en-us, en MIME-Version: 1.0 To: greg CC: linux-kernel@vger.kernel.org Subject: Re: Clock resolution / RT preemption References: <42EDD473.3010308@free.fr> In-Reply-To: <42EDD473.3010308@free.fr> 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 greg wrote: > Hi folks, > > I'm looking for a timer resolution lower than 1 ms (and monotonic clock > rate) destined to be used with some network code running on x86 > platforms. Would you please provide me with informations about how to > get/implement this. > > AFAIK, there's a "high resultion timer" patch hanging around, but > there's not much informations with regard to portability (specific > hardware requirements ?), scalability, integration with RT patches. > I understand the POSIX 1003.1b Clocks and Timers system calls are not > fully available within the linux kernel (and libc ?), am I right on that ? On the HRT web site (see signature) there is a CVS repository. In there is a special version for the RT kernel. As to porting it to other archs, have a look at the include/linux/hrtimer.h file. It has (or should have) all you need to know. Please pass back any port you do. > > One more question : I believe Ingo's preemption patch run > timers/interrupt handlers within kernel threads, how should I assign > specific priority to address my goals without compromising system > stability ? Carefully :) -- George Anzinger george@mvista.com HRT (High-res-timers): http://sourceforge.net/projects/high-res-timers/