Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423720Ab3FUTAs (ORCPT ); Fri, 21 Jun 2013 15:00:48 -0400 Received: from mail-ie0-f181.google.com ([209.85.223.181]:59517 "EHLO mail-ie0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423554Ab3FUTAo (ORCPT ); Fri, 21 Jun 2013 15:00:44 -0400 MIME-Version: 1.0 In-Reply-To: <20130621184434.GC26001@kroah.com> References: <1371831934-156971-1-git-send-email-nzimmer@sgi.com> <20130621184434.GC26001@kroah.com> Date: Fri, 21 Jun 2013 12:00:44 -0700 X-Google-Sender-Auth: ZLYzvAp2s4cC_s1Xacax9bsZkJA Message-ID: Subject: Re: [RFC 0/2] Delay initializing of large sections of memory From: Yinghai Lu To: Greg Kroah-Hartman Cc: Nathan Zimmer , Robin Holt , Mike Travis , Rob Landley , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andrew Morton , "the arch/x86 maintainers" , linux-doc@vger.kernel.org, Linux Kernel Mailing List Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1520 Lines: 37 On Fri, Jun 21, 2013 at 11:44 AM, Greg Kroah-Hartman wrote: > On Fri, Jun 21, 2013 at 11:36:21AM -0700, Yinghai Lu wrote: >> On Fri, Jun 21, 2013 at 9:25 AM, Nathan Zimmer wrote: >> > This rfc patch set delays initializing large sections of memory until we have >> > started cpus. This has the effect of reducing startup times on large memory >> > systems. On 16TB it can take over an hour to boot and most of that time >> > is spent initializing memory. >> >> One hour on system with 16T ram? BIOS or OS? >> >> I use wall clock to check bootime on one system with 3T and 16 pcie cards, >> Linus only takes about 3m and 30 seconds from bootloader. >> >> wonder if you boot delay is with so many cpu get onlined in serialized mode. >> >> so can you try boot your system with "maxcpus=128" to get the boot time with >> wall clock ? > > Why use the "wall clock" when we have the wonderful bootchart tools and > scripts that do this all for you, and can tell you exactly what part of > the kernel is taking what time, to help with fixing issues like this? bootchart is not completed. printk timestamp come after mem get initialized. .... [ 0.004000] tsc: Fast TSC calibration using PIT before that stamp are all 0. Yinghai -- 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/