From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 15 Sep 2001 13:57:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 15 Sep 2001 13:57:01 -0400 Received: from smtp10.atl.mindspring.net ([207.69.200.246]:11291 "EHLO smtp10.atl.mindspring.net") by vger.kernel.org with ESMTP id ; Sat, 15 Sep 2001 13:56:49 -0400 Subject: Re: Feedback on preemptible kernel patch From: Robert Love To: Arjan Filius Cc: linux-kernel@vger.kernel.org In-Reply-To: In-Reply-To: Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Evolution/0.13.99+cvs.2001.09.14.18.39 (Preview Release) Date: 15 Sep 2001 13:57:44 -0400 Message-Id: <1000576671.32708.23.camel@phantasy> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2001-09-15 at 05:44, Arjan Filius wrote: > Hi Robert, Hi Arjan, > Didn't discover yet, the only "strange" thing is when using > autocompleteion in a kterm in kde i get every time a kde crash-bug-report > popup message. however, no kernel messages or whatsoever. Odd. This does not occur without preemption enabled? > Well it's a fpu patch, and as far as i know i don't use the fpu that much > at the moment but i'll try that. Its a patch for when the kernel uses the FPU, specifically during MMX or 3DNow instructions. That is why iys for Athlon-optimized kernels, because the Athlon uses 3DNow instructions for some fast page copies. When the kernel uses FPU, it does not use SMP locks, since that is a per CPU condition. However, preemption can occur in the middle of a CPU doing that stuff, and that messes stuff up very much. The Athlon patch fixes it, it is much needed if your kernel is Athlon-optimized. Userspace FPU is controlled by the kernel already, so we don't need to worry about that. In userspace, the kernel handles everything ... in kernel land, if we want to go play with something (like 3DNow), we need to take care to set it up and restore ourselves properly. > in the hope finding the usage of fpu-irq: > sjoerd:/usr/src/linux # cat /proc/interrupts > CPU0 > 0: 13374740 XT-PIC timer > 1: 14581 XT-PIC keyboard > 2: 0 XT-PIC cascade > 9: 238018 XT-PIC usb-uhci, usb-uhci, EMU10K1 > 10: 601500 XT-PIC ide2, sym53c8xx > 11: 87300 XT-PIC eth0 > 12: 230338 XT-PIC PS/2 Mouse > 14: 331764 XT-PIC ide0 > 15: 39468 XT-PIC ide1 > NMI: 0 > ERR: 0 > > But /proc/interrupts shows only those irq's which are currently in use, is > there any way to show usage of currenlty unused interrupts? cat /proc/stat, see the `intr' line, each field is an increasing interrupt value. -- Robert M. Love rml at ufl.edu rml at tech9.net