From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756811AbYGaWMx (ORCPT ); Thu, 31 Jul 2008 18:12:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757619AbYGaWMm (ORCPT ); Thu, 31 Jul 2008 18:12:42 -0400 Received: from one.firstfloor.org ([213.235.205.2]:54056 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755195AbYGaWMl (ORCPT ); Thu, 31 Jul 2008 18:12:41 -0400 Date: Fri, 1 Aug 2008 00:12:47 +0200 From: Andi Kleen To: Ingo Molnar Cc: Jeremy Fitzhardinge , Nick Piggin , Andi Kleen , Linux Kernel Mailing List Subject: Re: [PATCH 2/2] x86: implement multiple queues for smp function call IPIs Message-ID: <20080731221247.GR23938@one.firstfloor.org> References: <488FA8A9.6000005@goop.org> <20080731220825.GD23801@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080731220825.GD23801@elte.hu> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Before going into all the fine details an trying our luck in tip/master > QA, i'm a bit worried about hw compatibility in general though. APICs > have been flaky since the beginnings of times. We had erratas in the > area of local timer IRQs(IPIs) overlapping with IPIs, etc. - so i'd not > bet the farm on all APICs being able to handle a _lot_ more overlapped > inter-CPU IPIs than we do currently. (which basically was just three of > them until now, and now four with the new SMP cross-call IPIs) At least on 64bit systems this configuration has been already tested for years with the 8 vector TLB flush. I am not aware of any problems caused by it. Using them on them should be fine. So your cautious approach would only be potentially useful on older 32bit only systems. -Andi