From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754182AbYHAE7B (ORCPT ); Fri, 1 Aug 2008 00:59:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752112AbYHAE6y (ORCPT ); Fri, 1 Aug 2008 00:58:54 -0400 Received: from gw.goop.org ([64.81.55.164]:47501 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751845AbYHAE6x (ORCPT ); Fri, 1 Aug 2008 00:58:53 -0400 Message-ID: <4892980A.2010101@goop.org> Date: Thu, 31 Jul 2008 21:58:50 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Ingo Molnar CC: Nick Piggin , Andi Kleen , Linux Kernel Mailing List Subject: Re: [PATCH 2/2] x86: implement multiple queues for smp function call IPIs References: <488FA8A9.6000005@goop.org> <20080731220825.GD23801@elte.hu> <48923B7A.3020805@goop.org> <20080731224202.GB22426@elte.hu> In-Reply-To: <20080731224202.GB22426@elte.hu> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > Yes on the 64-bit side we've had NUM_INVALIDATE_TLB_VECTORS (==8) for a > long time, but note that 64-bit is obviously for more modern CPUs. What > i'm mindful about (i'm not _that_ worried) are fragile APICs and unknown > erratas. > Well, the whole exercise is only useful if you have a relatively large number of CPUs, which presumably means you have relatively modern APICs. If we set the number of queues to 1 for < 4 CPUs, would that avoid the problem APICs? J