From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755804AbYCQHZ2 (ORCPT ); Mon, 17 Mar 2008 03:25:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752140AbYCQHZS (ORCPT ); Mon, 17 Mar 2008 03:25:18 -0400 Received: from brick.kernel.dk ([87.55.233.238]:8024 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751811AbYCQHZR (ORCPT ); Mon, 17 Mar 2008 03:25:17 -0400 Date: Mon, 17 Mar 2008 08:25:14 +0100 From: Jens Axboe To: Jeremy Fitzhardinge Cc: linux-kernel@vger.kernel.org, npiggin@suse.de, dgc@sgi.com Subject: Re: [PATCH 1/7] x86-64: introduce fast variant of smp_call_function_single() Message-ID: <20080317072514.GY17940@kernel.dk> References: <1205322940-20127-1-git-send-email-jens.axboe@oracle.com> <1205322940-20127-2-git-send-email-jens.axboe@oracle.com> <47DAC21C.1040805@goop.org> <20080316184506.GW17940@kernel.dk> <47DDA624.8000307@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <47DDA624.8000307@goop.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Mar 16 2008, Jeremy Fitzhardinge wrote: > Jens Axboe wrote: > >On Fri, Mar 14 2008, Jeremy Fitzhardinge wrote: > > > >>Jens Axboe wrote: > >> > >>>rom: Nick Piggin > >>> > >>> > >>Why is this necessary? How is smp_call_function_single slow? > >> > > > >Because it's completely serialized by the call_lock spinlock. > > > > Hm, yes. Would it be possible to implement smp_call_function_mask in a > generic way to avoid that? Turn the static structure into a per-cpu > request list? Have you looked at the patches you are replying to? :-) -- Jens Axboe