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, 1 Feb 2003 20:22:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 1 Feb 2003 20:22:57 -0500 Received: from willy.net1.nerim.net ([62.212.114.60]:15631 "EHLO www.home.local") by vger.kernel.org with ESMTP id ; Sat, 1 Feb 2003 20:22:56 -0500 Date: Sun, 2 Feb 2003 02:28:20 +0100 From: Willy Tarreau To: linux-kernel@vger.kernel.org Cc: Simon Kirby Subject: [Nearly Solved]: APIC routing broken on ASUS P2B-DS Message-ID: <20030202012820.GB19346@alpha.home.local> References: <20030128004906.GA3439@netnation.com> <20030128060629.GA19346@alpha.home.local> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030128060629.GA19346@alpha.home.local> User-Agent: Mutt/1.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 28, 2003 at 07:06:29AM +0100, Willy Tarreau wrote: > On Mon, Jan 27, 2003 at 04:49:06PM -0800, Simon Kirby wrote: > > Something broke between 2.4.20 and 2.4.21-pre3 which is causing > > interrupts to not be routed the second CPU. I saw the problem on one box > > and copied the kernel to another which then had the same problem (both > > ASUS P2B-DS boards, one with PIII CPUs, one with PII CPUs). Hi ! I noticed that 2.4.21-pre4 had the same problem whereas -ac1 and -aa1 worked fine. But unfortunately, this was unrelated since both use irq_balance which seems to work around or fix the problem. So I searched back the earlier versions, and finally narrowed this problem down to the introduction of CONFIG_X86_NUMA and associated code in 2.4.21pre1. If I compile my kernel for an SMP K7, only CPU0 gets the interrupts. But if I enable CONFIG_X86_CLUSTERED_APIC by enabling either CONFIG_X86_NUMAQ or CONFIG_X86_SUMMIT (CONFIG_X86_NUMA alone isn't enough), then I get my interrupts distributed across both CPUs. This is on an Asus A7M266D with 2 Athlon XP 1800+. I don't know if this option can affect performance or stability. BTW, the system runs in Flat APIC mode, as reported at boot time. I can provide dmesg on request, but didn't want to pollute the list. I looked through the code but since I don't know much about APIC, I didn't understand the changes nor how they would affect what I observed. Anyone has any clue ? Cheers, Willy