From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id 03C4C6B0069 for ; Thu, 24 Nov 2016 18:59:27 -0500 (EST) Received: by mail-pg0-f71.google.com with SMTP id g186so136171486pgc.2 for ; Thu, 24 Nov 2016 15:59:26 -0800 (PST) Received: from mail-pg0-x241.google.com (mail-pg0-x241.google.com. [2607:f8b0:400e:c05::241]) by mx.google.com with ESMTPS id a3si12878495plc.322.2016.11.24.15.59.26 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 24 Nov 2016 15:59:26 -0800 (PST) Received: by mail-pg0-x241.google.com with SMTP id 3so4291645pgd.0 for ; Thu, 24 Nov 2016 15:59:26 -0800 (PST) Subject: Re: [PATCH 0/5] Parallel hugepage migration optimization References: <20161122162530.2370-1-zi.yan@sent.com> From: Balbir Singh Message-ID: <9cf7f4c6-6dde-9dbb-cf93-7874437a442d@gmail.com> Date: Fri, 25 Nov 2016 10:59:20 +1100 MIME-Version: 1.0 In-Reply-To: <20161122162530.2370-1-zi.yan@sent.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Zi Yan , linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: akpm@linux-foundation.org, minchan@kernel.org, vbabka@suse.cz, mgorman@techsingularity.net, kirill.shutemov@linux.intel.com, n-horiguchi@ah.jp.nec.com, khandual@linux.vnet.ibm.com, Zi Yan On 23/11/16 03:25, Zi Yan wrote: > From: Zi Yan > > Hi all, > > This patchset boosts the hugepage migration throughput and helps THP migration > which is added by Naoya's patches: https://lwn.net/Articles/705879/. > > Motivation > =============================== > > In x86, 4KB page migrations are underutilizing the memory bandwidth compared > to 2MB THP migrations. I did some page migration benchmarking on a two-socket > Intel Xeon E5-2640v3 box, which has 23.4GB/s bandwidth, and discover > there are big throughput gap, ~3x, between 4KB and 2MB page migrations. > > Here are the throughput numbers for different page sizes and page numbers: > | 512 4KB pages | 1 2MB THP | 1 4KB page > x86_64 | 0.98GB/s | 2.97GB/s | 0.06GB/s > > As Linux currently use single-threaded page migration, the throughput is still > much lower than the hardware bandwidth, 2.97GB/s vs 23.4GB/s. So I parallelize > the copy_page() part of THP migration with workqueue and achieve 2.8x throughput. > > Here are the throughput numbers of 2MB page migration: > | single-threaded | 8-thread > x86_64 2MB | 2.97GB/s | 8.58GB/s > Whats the impact on CPU utilization? Is there a huge impact? Balbir Singh. -- 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