From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yh0-f47.google.com (mail-yh0-f47.google.com [209.85.213.47]) by kanga.kvack.org (Postfix) with ESMTP id 55E166B0038 for ; Tue, 28 Apr 2015 14:38:23 -0400 (EDT) Received: by yhcb70 with SMTP id b70so852753yhc.0 for ; Tue, 28 Apr 2015 11:38:23 -0700 (PDT) Received: from relay.sgi.com (relay1.sgi.com. [192.48.180.66]) by mx.google.com with ESMTP id fj3si36370489vdb.81.2015.04.28.11.38.22 for ; Tue, 28 Apr 2015 11:38:22 -0700 (PDT) Message-ID: <553FD39C.2070503@sgi.com> Date: Tue, 28 Apr 2015 13:38:20 -0500 From: nzimmer MIME-Version: 1.0 Subject: Re: [PATCH 0/13] Parallel struct page initialisation v4 References: <1430231830-7702-1-git-send-email-mgorman@suse.de> In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Pekka Enberg , Mel Gorman Cc: Andrew Morton , Dave Hansen , Waiman Long , Scott Norton , Daniel J Blueman , Linux-MM , LKML On an older 8 TB box with lots and lots of cpus the boot time, as measure from grub to login prompt, the boot time improved from 1484 seconds to exactly 1000 seconds. I have time on 16 TB box tonight and a 12 TB box thursday and will hopefully have more numbers then. On 04/28/2015 11:06 AM, Pekka Enberg wrote: > On Tue, Apr 28, 2015 at 5:36 PM, Mel Gorman wrote: >> Struct page initialisation had been identified as one of the reasons why >> large machines take a long time to boot. Patches were posted a long time ago >> to defer initialisation until they were first used. This was rejected on >> the grounds it should not be necessary to hurt the fast paths. This series >> reuses much of the work from that time but defers the initialisation of >> memory to kswapd so that one thread per node initialises memory local to >> that node. >> >> After applying the series and setting the appropriate Kconfig variable I >> see this in the boot log on a 64G machine >> >> [ 7.383764] kswapd 0 initialised deferred memory in 188ms >> [ 7.404253] kswapd 1 initialised deferred memory in 208ms >> [ 7.411044] kswapd 3 initialised deferred memory in 216ms >> [ 7.411551] kswapd 2 initialised deferred memory in 216ms >> >> On a 1TB machine, I see >> >> [ 8.406511] kswapd 3 initialised deferred memory in 1116ms >> [ 8.428518] kswapd 1 initialised deferred memory in 1140ms >> [ 8.435977] kswapd 0 initialised deferred memory in 1148ms >> [ 8.437416] kswapd 2 initialised deferred memory in 1148ms >> >> Once booted the machine appears to work as normal. Boot times were measured >> from the time shutdown was called until ssh was available again. In the >> 64G case, the boot time savings are negligible. On the 1TB machine, the >> savings were 16 seconds. > FWIW, > > Acked-by: Pekka Enberg > > for the whole series. > > - Pekka -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org