Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754551AbbDOQTI (ORCPT ); Wed, 15 Apr 2015 12:19:08 -0400 Received: from g1t5424.austin.hp.com ([15.216.225.54]:34285 "EHLO g1t5424.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751838AbbDOQTD (ORCPT ); Wed, 15 Apr 2015 12:19:03 -0400 Message-ID: <552E8F72.408@hp.com> Date: Wed, 15 Apr 2015 12:18:58 -0400 From: Waiman Long User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.12) Gecko/20130109 Thunderbird/10.0.12 MIME-Version: 1.0 To: Peter Zijlstra CC: Mel Gorman , Linux-MM , Nathan Zimmer , Daniel Rahn , Davidlohr Bueso , Dave Hansen , Tom Vaden , Scott Norton , LKML Subject: Re: [RFC PATCH 0/14] Parallel memory initialisation References: <1428920226-18147-1-git-send-email-mgorman@suse.de> <552E6486.6070705@hp.com> <20150415142731.GI17717@twins.programming.kicks-ass.net> <20150415143420.GG14842@suse.de> <20150415144818.GX5029@twins.programming.kicks-ass.net> In-Reply-To: <20150415144818.GX5029@twins.programming.kicks-ass.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1810 Lines: 36 On 04/15/2015 10:48 AM, Peter Zijlstra wrote: > On Wed, Apr 15, 2015 at 03:34:20PM +0100, Mel Gorman wrote: >> On Wed, Apr 15, 2015 at 04:27:31PM +0200, Peter Zijlstra wrote: >>> On Wed, Apr 15, 2015 at 09:15:50AM -0400, Waiman Long wrote: >>>> I had included your patch with the 4.0 kernel and booted up a 16-socket >>>> 12-TB machine. I measured the elapsed time from the elilo prompt to the >>>> availability of ssh login. Without the patch, the bootup time was 404s. It >>>> was reduced to 298s with the patch. So there was about 100s reduction in >>>> bootup time (1/4 of the total). >>> But you cheat! :-) >>> >>> How long between power on and the elilo prompt? Do the 100 seconds >>> matter on that time scale? >> Calling it cheating is a *bit* harsh as the POST times vary considerably >> between manufacturers. While I'm interested in Waiman's answer, I'm told >> that those that really care about minimising reboot times will use kexec >> to avoid POST. The 100 seconds is 100 seconds, whether that is 25% in >> all cases is a different matter. > Sure POST times vary, but its consistently stupid long :-) I'm forever > thinking my EX machine died because its not coming back from a power > cycle, and mine isn't really _that_ large. I agree with that. I always complain about the long POST time of those server machines. As for Mel's patch, what I wanted to show is its impact on the OS bootup part of the boot process. We have no control on how long the firmware POST is, so there is no point in lumping them into the discussion. Cheers, Longman -- 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/