From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Howard Subject: Re: controlling ACPI IRQ routing Date: Sun, 06 Jan 2008 08:38:02 -0800 Message-ID: <478103EA.6070503@howardsilvan.com> References: <47742083.5060903@howardsilvan.com> <47769494.3080503@howardsilvan.com> <20080102151142.73362648@citycable.ch> <200801050051.20947.lenb@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from frodo.howardsilvan.com ([66.119.206.113]:37671 "EHLO mail.howardsilvan.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756541AbYAFQiE (ORCPT ); Sun, 6 Jan 2008 11:38:04 -0500 In-Reply-To: <200801050051.20947.lenb@kernel.org> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Len Brown Cc: linux-acpi@vger.kernel.org Len Brown wrote: > On Wednesday 02 January 2008 09:11, Dominique Michel wrote: > =20 >> Le Sat, 29 Dec 2007 10:40:20 -0800, >> Lee Howard a =C3=A9crit : >> >> >> =20 >>> # cat /proc/interrupts >>> CPU0 =20 >>> 0: 1051464247 IO-APIC-edge timer >>> 1: 8 IO-APIC-edge i8042 >>> 8: 0 IO-APIC-edge rtc >>> 9: 0 IO-APIC-fasteoi acpi >>> 12: 104 IO-APIC-edge i8042 >>> 14: 9414304 IO-APIC-edge ide0 >>> 16: 1051172722 IO-APIC-fasteoi wct4xxp >>> 19: 1 IO-APIC-fasteoi eth1 >>> 21: 158008518 IO-APIC-fasteoi eth0 >>> 22: 6974044 IO-APIC-fasteoi libata >>> 23: 7071112 IO-APIC-fasteoi libata >>> NMI: 0 >>> LOC: 1051371544 >>> ERR: 0 >>> >>> >>> =20 >> Based on that, you may want to use rtirq. It is a boot script (need = schedutils >> as dependency) with associated config scripts. http://alsa.opensrc.o= rg/Rtirq >> >> In /etc/conf.d/rtirq, you will find: >> >> # IRQ thread service names >> # (space separated list, from higher to lower priority). >> RTIRQ_NAME_LIST=3D"rtc snd usb i8042" >> >> The most important things is that the devices listed here doesn't ha= ve any >> shared IRQ with some other device and that the rtc remain the first = listed >> device (the one with the higer priority), or the system will hang so= on or later. >> >> This setup is for audio workstation but is very easy to adapt to any= kind of >> work. >> >> =20 > > I've got no experience with the thread priority thing above. > However, the better way to handle quality of service contention > is to not do the things you don't care about. > > Does the system really need HZ=3D1000? you could slow that down to 1= 00, > or run CONFIG_NO_HZ to reduce it even more... > Also, on a UP, the LAPIC timer interrupt is redundant -- > you could build your kernel w/o APIC support or boot with nolapic. > > This would get rid of the only interrupts which are frequent > enough to be competing with the device, clock ticks. If I boot with nolapic then XT-PIC is used, and the wcfxo device ends u= p=20 sharing an IRQ with libata which results in worse performance than with= =20 it the way that it is. Thanks, Lee. - To unsubscribe from this list: send the line "unsubscribe linux-acpi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html