From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752631Ab2GTTlV (ORCPT ); Fri, 20 Jul 2012 15:41:21 -0400 Received: from mail-yw0-f46.google.com ([209.85.213.46]:39872 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751570Ab2GTTlT (ORCPT ); Fri, 20 Jul 2012 15:41:19 -0400 Date: Fri, 20 Jul 2012 12:41:14 -0700 From: Tejun Heo To: "Rafael J. Wysocki" Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, tglx@linutronix.de, linux-pm@vger.kernel.org Subject: Re: [PATCHSET] workqueue: reimplement CPU hotplug to keep idle workers Message-ID: <20120720194114.GA21218@google.com> References: <1342545149-3515-1-git-send-email-tj@kernel.org> <1342808550.2583.48.camel@twins> <20120720183400.GL32763@google.com> <201207202144.05154.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201207202144.05154.rjw@sisk.pl> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Rafael. On Fri, Jul 20, 2012 at 09:44:04PM +0200, Rafael J. Wysocki wrote: > Well, there are use cases I'm not really familiar with. > > Pretty much the only use case I'm sufficiently familiar with is > suspend/hibernate where we unplug all of the nonboot CPUs at one point. > > The other use cases, which I don't really think are entirely valid, > are on some ARM platforms where CPUs are unplugged instead of being put into > C-states or equivalent (because we don't have a good mechanism for handling > multiprocessor C-states; there's a set of patches for that waiting for > the merge window in the Len's tree). I'm hoping to get rid of those > use cases in future entirely. I see, so the highest frequency user would most likely be suspend/resume - especially with opportunistic approach like the one used in androids. Thanks for the explanation. -- tejun