Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946178Ab3FUV2q (ORCPT ); Fri, 21 Jun 2013 17:28:46 -0400 Received: from relay2.sgi.com ([192.48.179.30]:36117 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1946138Ab3FUV2o (ORCPT ); Fri, 21 Jun 2013 17:28:44 -0400 Message-ID: <51C4C58A.1010307@sgi.com> Date: Fri, 21 Jun 2013 14:28:42 -0700 From: Mike Travis User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130509 Thunderbird/17.0.6 MIME-Version: 1.0 To: Yinghai Lu CC: Greg Kroah-Hartman , Nathan Zimmer , Robin Holt , Rob Landley , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andrew Morton , the arch/x86 maintainers , linux-doc@vger.kernel.org, Linux Kernel Mailing List Subject: Re: [RFC 0/2] Delay initializing of large sections of memory References: <1371831934-156971-1-git-send-email-nzimmer@sgi.com> <20130621184434.GC26001@kroah.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1861 Lines: 47 On 6/21/2013 12:00 PM, Yinghai Lu wrote: > 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 > On UV the system console function has an option to include timestamps, both sequential in HH:MM:SS and deltas to 100ms. So we get both the BIOS and system times before printk time is active. We also have a custom "script" command that adds timing info. -- 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/