Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755974Ab1BHXgA (ORCPT ); Tue, 8 Feb 2011 18:36:00 -0500 Received: from db3ehsobe006.messaging.microsoft.com ([213.199.154.144]:42909 "EHLO DB3EHSOBE006.bigfish.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755514Ab1BHXf6 (ORCPT ); Tue, 8 Feb 2011 18:35:58 -0500 X-SpamScore: -15 X-BigFish: VPS-15(zzbb2dK1432N98dNzz1202hzzz2fh2a8h637h668h62h) X-Spam-TCS-SCL: 1:0 X-Forefront-Antispam-Report: KIP:(null);UIP:(null);IPVD:NLI;H:mail7.fw-bc.sony.com;RD:mail7.fw-bc.sony.com;EFVD:NLI Message-ID: <4D51D341.3040209@am.sony.com> Date: Tue, 8 Feb 2011 15:35:29 -0800 From: Frank Rowand Reply-To: User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.1) Gecko/20090814 Fedora/3.0-2.6.b3.fc11 Thunderbird/3.0b3 MIME-Version: 1.0 To: Ingo Molnar CC: "Rafael J. Wysocki" , Linus Torvalds , Mark Brown , Len Brown , Alan Stern , , , Andrew Morton , Dmitry Torokhov , , Thomas Gleixner Subject: Re: [PATCH] Remove CONFIG_PM altogether, enable power management all the time References: <1297081335-13631-1-git-send-email-broonie@opensource.wolfsonmicro.com> <201102072046.48763.rjw@sisk.pl> <20110207201803.GU10564@opensource.wolfsonmicro.com> <201102072215.59921.rjw@sisk.pl> <20110208122159.GA8284@elte.hu> In-Reply-To: <20110208122159.GA8284@elte.hu> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-OriginatorOrg: am.sony.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2197 Lines: 68 On 02/08/11 04:21, Ingo Molnar wrote: < snip > > Also, i've Cc:-ed Linus, to check whether the idea to make power management a > permanent, core portion of Linux has any obvious downsides we missed. > > Rafael, could you do a defconfig-ish x86 build with and without CONFIG_PM, and post > the 'size vmlinux' comparison - so that we can see the size difference? We make some > things CONFIG_EXPERT configurable just to enable folks who *really* want to cut down > on kernel size to configure it out. For 2.6.38-rc4, x86_64, CONFIG_NR_CPUS=4: size vmlinux text data bss dec hex filename 6553910 3555020 9994240 20103170 132c002 vmlinux with CONFIG_PM 6512652 3553116 9994240 20060008 1321768 vmlinux without CONFIG_PM 41258 1904 0 43162 delta That is big enough for me to care. Turning on CONFIG_PM also forces a few other options on: 295a296 > CONFIG_XEN_SAVE_RESTORE=y 422c423,431 < # CONFIG_PM is not set --- > CONFIG_PM=y > # CONFIG_PM_DEBUG is not set > CONFIG_PM_SLEEP_SMP=y > CONFIG_PM_SLEEP=y > # CONFIG_SUSPEND is not set > # CONFIG_HIBERNATION is not set > # CONFIG_PM_RUNTIME is not set > CONFIG_PM_OPS=y > # CONFIG_ACPI is not set 451,454c460 < CONFIG_CPU_IDLE=y < CONFIG_CPU_IDLE_GOV_LADDER=y < CONFIG_CPU_IDLE_GOV_MENU=y < # CONFIG_INTEL_IDLE is not set --- > # CONFIG_CPU_IDLE is not set > > Note that those usecases, even if they want a super-small kernel, might not care > about PM at all while they care about size: small boot kernels in ROMs, or simple > devices where CPU-idling implies deep low power mode, etc. > > So the vmlinux size comparisons would be needed really. If it's 5k nobody will care. > If it's 50k-100k that's borderline. In the other side of the scale we have the 1500+ > #ifdef CONFIG_PM lines strewn around the kernel source, and the frequent !PM build > breakages. > > Ingo -Frank -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/