Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755421AbbDOOsh (ORCPT ); Wed, 15 Apr 2015 10:48:37 -0400 Received: from casper.infradead.org ([85.118.1.10]:35934 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755019AbbDOOsa (ORCPT ); Wed, 15 Apr 2015 10:48:30 -0400 Date: Wed, 15 Apr 2015 16:48:18 +0200 From: Peter Zijlstra To: Mel Gorman Cc: Waiman Long , Linux-MM , Nathan Zimmer , Daniel Rahn , Davidlohr Bueso , Dave Hansen , Tom Vaden , Scott Norton , LKML Subject: Re: [RFC PATCH 0/14] Parallel memory initialisation Message-ID: <20150415144818.GX5029@twins.programming.kicks-ass.net> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150415143420.GG14842@suse.de> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1445 Lines: 28 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. -- 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/