From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f170.google.com (mail-pf0-f170.google.com [209.85.192.170]) by kanga.kvack.org (Postfix) with ESMTP id 9076E6B007E for ; Thu, 3 Mar 2016 02:02:11 -0500 (EST) Received: by mail-pf0-f170.google.com with SMTP id w128so9740622pfb.2 for ; Wed, 02 Mar 2016 23:02:11 -0800 (PST) Received: from mail-pa0-x241.google.com (mail-pa0-x241.google.com. [2607:f8b0:400e:c03::241]) by mx.google.com with ESMTPS id vb13si2470790pab.68.2016.03.02.23.02.10 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 Mar 2016 23:02:10 -0800 (PST) Received: by mail-pa0-x241.google.com with SMTP id fl4so797877pad.2 for ; Wed, 02 Mar 2016 23:02:10 -0800 (PST) From: Li Zhang Subject: [PATCH RFC 0/2] mm: Enable page parallel initialisation for Power Date: Thu, 3 Mar 2016 15:01:39 +0800 Message-Id: <1456988501-29046-1-git-send-email-zhlcindy@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: mpe@ellerman.id.au, khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, mgorman@techsingularity.net Cc: linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Li Zhang From: Li Zhang Uptream has supported page parallel initialisation for X86 and the boot time is improved greately. Some tests have been done for Power. Here is the result I have done with different memory size. * 4GB memory: boot time is as the following: with patch vs without patch: 10.4s vs 24.5s boot time is improved 57% * 200GB memory: boot time looks the same with and without patches. boot time is about 38s * 32TB memory: boot time looks the same with and without patches boot time is about 160s. The boot time is much shorter than X86 with 24TB memory. From community discussion, it costs about 694s for X86 24T system. >>From code view, parallel initialisation improve the performance by deferring memory initilisation to kswap with N kthreads, it should improve the performance therotically. >>From the test result, On X86, performance is improved greatly with huge memory. But on Power platform, it is improved greatly with less than 100GB memory. For huge memory, it is not improved greatly. But it saves the time with several threads at least, as the following information shows(32TB system log): [ 22.648169] node 9 initialised, 16607461 pages in 280ms [ 22.783772] node 3 initialised, 23937243 pages in 410ms [ 22.858877] node 6 initialised, 29179347 pages in 490ms [ 22.863252] node 2 initialised, 29179347 pages in 490ms [ 22.907545] node 0 initialised, 32049614 pages in 540ms [ 22.920891] node 15 initialised, 32212280 pages in 550ms [ 22.923236] node 4 initialised, 32306127 pages in 550ms [ 22.923384] node 12 initialised, 32314319 pages in 550ms [ 22.924754] node 8 initialised, 32314319 pages in 550ms [ 22.940780] node 13 initialised, 33353677 pages in 570ms [ 22.940796] node 11 initialised, 33353677 pages in 570ms [ 22.941700] node 5 initialised, 33353677 pages in 570ms [ 22.941721] node 10 initialised, 33353677 pages in 570ms [ 22.941876] node 7 initialised, 33353677 pages in 570ms [ 22.944946] node 14 initialised, 33353677 pages in 570ms [ 22.946063] node 1 initialised, 33345485 pages in 580ms It saves the time about 550*16 ms at least, although it can be ignore to compare the boot time about 160 seconds. What's more, the boot time is much shorter on Power even without patches than x86 for huge memory machine. So this patchset is still necessary to be enabled for Power. Li Zhang (2): mm: meminit: initialise more memory for inode/dentry hash tables in early boot Enable page parallel initialisation arch/powerpc/Kconfig | 1 + mm/page_alloc.c | 11 +++++++++-- 2 files changed, 10 insertions(+), 2 deletions(-) -- 2.1.0 -- 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