From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Howard Subject: Re: controlling ACPI IRQ routing Date: Sat, 29 Dec 2007 10:40:20 -0800 Message-ID: <47769494.3080503@howardsilvan.com> References: <47742083.5060903@howardsilvan.com> <477489B8.20700@howardsilvan.com> <1198821979.20548.9.camel@sli10-desk.sh.intel.com> <200712290339.48354.lenb@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from frodo.howardsilvan.com ([66.119.206.113]:60577 "EHLO mail.howardsilvan.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754749AbXL2SkX (ORCPT ); Sat, 29 Dec 2007 13:40:23 -0500 In-Reply-To: <200712290339.48354.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: > 1000 interrupts/second isn't a lot on modern hardware. > Indeed, many linux distros run with 1000 clock ticks/second today. > > I don't understand why interrupt priority has anything to do > with what you are seeing. To notice such a thing, you'd have > to have a lot of competing interrupts firing at the same time > and the messages queued up inside the LAPIC and the processor > spending a large % of its time in interrupt context. > (does top(1) say that you're running a large %sys?) > No, top says nothing unusual to me... top - 13:36:50 up 12 days, 4:00, 1 user, load average: 0.01, 0.05, 0.05 Tasks: 189 total, 1 running, 185 sleeping, 0 stopped, 3 zombie Cpu(s): 0.7% us, 1.3% sy, 0.0% ni, 97.7% id, 0.0% wa, 0.0% hi, 0.3% si, 0.0% st Mem: 2054796k total, 2018560k used, 36236k free, 239084k buffers Swap: 2007992k total, 520k used, 2007472k free, 1266672k cached > What is the total interrupt rate on the system when this > device is doing 1000/second? > I don't understand the question, really... and I'm not sure how to determine the answer, either. Here's what /proc/interrupts says: # cat /proc/interrupts CPU0 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 > Are there multiple cores on the system? No, otherwise it appears that I could use IRQ affinity to dedicate a processor to handling the wct4xxp (zaptel) interrupt. > If so, > are the interrupts bound to certain cores or is > irqbalance running? irqbalance is available and running, but I don't think that it does anything on a single-core system. Thanks, Lee.