From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 12 Oct 2001 14:38:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 12 Oct 2001 14:38:49 -0400 Received: from colorfullife.com ([216.156.138.34]:24587 "EHLO colorfullife.com") by vger.kernel.org with ESMTP id ; Fri, 12 Oct 2001 14:38:37 -0400 Message-ID: <3BC738AD.A0329BBF@colorfullife.com> Date: Fri, 12 Oct 2001 20:38:37 +0200 From: Manfred Spraul X-Mailer: Mozilla 4.76 [en] (X11; U; Linux 2.4.12 i686) X-Accept-Language: en, de MIME-Version: 1.0 To: "Martin J. Bligh" , linux-kernel@vger.kernel.org, Sean Cavanaugh Subject: Re: P4 SMP load balancing Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit > > ovendev:~# cat /proc/interrupts > > CPU0 CPU1 > > 0: 6348212 0 IO-APIC-edge timer > > 1: 2 0 IO-APIC-edge keyboard > > 2: 0 0 XT-PIC cascade > > 8: 1 0 IO-APIC-edge rtc > > 9: 0 0 IO-APIC-edge acpi > > 16: 92620 0 IO-APIC-level eth0 > > 18: 5085 0 IO-APIC-level aic7xxx, aic7xxx > > NMI: 0 0 > > LOC: 6348388 6348427 > > ERR: 0 > > MIS: 0 > > I don't think this should happen. In the event of both procs having equal > priority (linux never changes them, so they always do), we should fall back > to the arbitration priority of the lapic. Whether you have 1 or 2 I/O apics > working shouldn't make a difference. The P 4 has a new apic, and lowest priority delivery doesn't work anymore. <<<<<<< Chapter 7.6.10 of 24547202.pdf In operating systems that use the lowest priority interrupt delivery mode but do not update the TPR, the TPR information saved in the chipset will potentially cause the interrupt to be always delivered to the same processor from the logical set. This behavior is functionally backward compatible with the P6 family processor but may result in unexpected performance implications. <<<<<<< (search for 245472 on google for the pdf file) -- Manfred