Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267936AbUJOOmX (ORCPT ); Fri, 15 Oct 2004 10:42:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267943AbUJOOmX (ORCPT ); Fri, 15 Oct 2004 10:42:23 -0400 Received: from kinesis.swishmail.com ([209.10.110.86]:26898 "EHLO kinesis.swishmail.com") by vger.kernel.org with ESMTP id S267936AbUJOOmS (ORCPT ); Fri, 15 Oct 2004 10:42:18 -0400 Message-ID: <416FE42A.3010305@techsource.com> Date: Fri, 15 Oct 2004 10:52:26 -0400 From: Timothy Miller MIME-Version: 1.0 To: Mark_H_Johnson@raytheon.com CC: Ingo Molnar , Andrew Morton , Bill Huey , Dipankar Sarma , Adam Heath , Daniel Walker , "K.R. Foley" , linux-kernel@vger.kernel.org, Lorenzo Allegrucci , Lee Revell , Rui Nuno Capela Subject: Re: [patch] Real-Time Preemption, -VP-2.6.9-rc4-mm1-U1 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: 1326 Lines: 30 Mark_H_Johnson@raytheon.com wrote: > > In the systems I have to deal with, I do not have a clear criteria > to set priorities of interrupts relative to each other. For example, I > have a real time simulation system using the following devices: > - occasional disk access to simulate disk I/O > - real time network traffic > - real time delivery of interrupts from a PCI timer card and APIC timers > - real time interrupts from a shared memory interface > The priorities of real time tasks are basically assigned based on the > rate of execution. 80 Hz tasks run at a higher priority than 60 Hz, 60 Hz > > 40 Hz, and so on. A number of tasks can access each device. > What if drivers could indicate how much "jitter" (essentially, latency) its interrupts can tolerate? Higher jitter would SORTOF translate into lower priority, although the scheduler would make sure the IRQ was started before its tolerance ran out (ie. the priority approaches infinity as its tolerance period approaches the end). The jitter tolerance would be measured in microseconds, I guess. - 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/