From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754439Ab2AaNm2 (ORCPT ); Tue, 31 Jan 2012 08:42:28 -0500 Received: from casper.infradead.org ([85.118.1.10]:51789 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753343Ab2AaNm1 (ORCPT ); Tue, 31 Jan 2012 08:42:27 -0500 Date: Tue, 31 Jan 2012 05:43:51 -0800 From: Arjan van de Ven To: Ingo Molnar Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, x86@kernel.org, arjanvandeven@gmail.com, Thomas Gleixner Subject: Re: x86: clean up smpboot.c's use of udelay+schedule Message-ID: <20120131054351.0a9f35ed@infradead.org> In-Reply-To: <20120131125331.GE4408@elte.hu> References: <20120130205304.0e10b05e@infradead.org> <20120131124341.GC4408@elte.hu> <1328014076.2446.210.camel@twins> <20120131125331.GE4408@elte.hu> Organization: Intel X-Mailer: Claws Mail 3.7.9 (GTK+ 2.24.7; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 31 Jan 2012 13:53:32 +0100 Ingo Molnar wrote: > > Wanna give a short TODO list to anyone wanting to work on that? the biggest thing that needs to happen is splitting the hardware specific part ("bring the chip up") and the OS specific part of cpu_up() ("get the cpu into our accounting/awareness"). the former does not need the hotplug or any other big lock (just a state machine), the later needs the hotplug lock for obvious reasons. The former is the part that takes a long time (> 100msec for a first cpu in a package, > 30msec for second and later), the later is quick. -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org