From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1945986Ab3FUUF0 (ORCPT ); Fri, 21 Jun 2013 16:05:26 -0400 Received: from relay1.sgi.com ([192.48.179.29]:52038 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423580Ab3FUUFZ (ORCPT ); Fri, 21 Jun 2013 16:05:25 -0400 Message-ID: <51C4B20B.20201@sgi.com> Date: Fri, 21 Jun 2013 15:05:31 -0500 From: Nathan Zimmer User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130510 Thunderbird/17.0.6 MIME-Version: 1.0 To: "H. Peter Anvin" CC: Greg KH , , , , , , , , , , Subject: Re: [RFC 0/2] Delay initializing of large sections of memory References: <1371831934-156971-1-git-send-email-nzimmer@sgi.com> <20130621165142.GA32125@kroah.com> <51C48745.9030304@zytor.com> <51C48ADD.207@sgi.com> <51C48D5A.4010602@zytor.com> In-Reply-To: <51C48D5A.4010602@zytor.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [128.162.233.140] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/21/2013 12:28 PM, H. Peter Anvin wrote: > On 06/21/2013 10:18 AM, Nathan Zimmer wrote: >>> Since you made it a compile time option, it would be good to know how >>> much code it adds, but otherwise I agree with Greg here... this really >>> shouldn't need to be an option. It *especially* shouldn't need to be a >>> hand-set runtime option (which looks quite complex, to boot.) >> The patchset as a whole is just over 400 lines so it doesn't add alot. >> If I were to pull the .config option it would probably remove 30 lines. > I'm more concerned about bytes of code. Oh, The difference is just under 32k. 371843425 Jun 21 14:08 vmlinux.o /* DELAY_MEM_INIT is not set */ 371875600 Jun 21 14:36 vmlinux.o /* DELAY_MEM_INIT=y */ > >> The command line option is too complex but some of the data I haven't >> found a way to get at runtime yet. > I think that is probably key. > >>> I suspect the cutoff for this should be a lot lower than 8 TB even, more >>> like 128 GB or so. The only concern is to not set the cutoff so low >>> that we can end up running out of memory or with suboptimal NUMA >>> placement just because of this. >> Even at lower amounts of ram there is an positive impact.I it knocks >> time off >> boot even at as small as a 1TB of ram. > I am not surprised. > > -hpa >