From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17C8DC4361B for ; Mon, 14 Dec 2020 02:04:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9C25F21D94 for ; Mon, 14 Dec 2020 02:04:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9C25F21D94 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=joelfernandes.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 8C1266B0036; Sun, 13 Dec 2020 21:04:00 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 871D96B005C; Sun, 13 Dec 2020 21:04:00 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 786C96B005D; Sun, 13 Dec 2020 21:04:00 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0237.hostedemail.com [216.40.44.237]) by kanga.kvack.org (Postfix) with ESMTP id 63C7F6B0036 for ; Sun, 13 Dec 2020 21:04:00 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 2A98F181AEF1A for ; Mon, 14 Dec 2020 02:04:00 +0000 (UTC) X-FDA: 77590242240.23.anger71_3b139c327417 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin23.hostedemail.com (Postfix) with ESMTP id 0F19537604 for ; Mon, 14 Dec 2020 02:04:00 +0000 (UTC) X-HE-Tag: anger71_3b139c327417 X-Filterd-Recvd-Size: 6405 Received: from mail-qt1-f194.google.com (mail-qt1-f194.google.com [209.85.160.194]) by imf46.hostedemail.com (Postfix) with ESMTP for ; Mon, 14 Dec 2020 02:03:59 +0000 (UTC) Received: by mail-qt1-f194.google.com with SMTP id f14so10890384qto.12 for ; Sun, 13 Dec 2020 18:03:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=3joCMQEgMYTRWtwvNU8XfkRxQvl1XcPWoJqmHhlAjNg=; b=jIFuMyW0CXPwPbzjytq1fyl28f5h7j18cK1dq9/kuoMitNcBn2VPPr+iiAdwiyshf8 Sass69snymAmlv2w9RPxsB1q6+LKmXCPfpDzo0XV15UccAlREbVBq+V+jHCI6ci5QwI2 xW3KXMx8jhphyq6rezDemv6LqKppWr9EI6OjM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=3joCMQEgMYTRWtwvNU8XfkRxQvl1XcPWoJqmHhlAjNg=; b=EQZ5oveZrf5il6B9aoElhBDB3EMrjE1xZfmuO/cqTAEVQvqXRB5U/SONnN7JY3mtVJ hAotH4TBR2PpYQDSroj77vayfTUpFaFDpMMHWj1p6sg3vNfpbameqcj8mcgcLx21o6EH vw9ubYwdhBg0+8CS4ZnLgxuetP2kWAhNSql6LOBFbY6dRwEBekL0pAbWsJYPw1w2w4+S pbNhda/JIaQqhwVQhBmZV0YaIP9jmrrrTJz4nDTbwd44IjmhnfByGaM3QKXh2+Ve8j6K IDGoLW5jlfKvnno4/PsPpGHP5H98Wvyex/n64pORMli5sec0gpTzcqljnEpVaP2sIBNO 2V+w== X-Gm-Message-State: AOAM532XuvdAAdBQmY+z3Q2bEmDGuTkZlueCskf5E6VxTlYQDkEm7DMl 58X13us1ZV0SmtuLXbZ5W7ZdgA== X-Google-Smtp-Source: ABdhPJyNrnChYZI79mij49ui4I23lfJGjf54I4Witq/Vsja69LURczot4O1GWdNPlqyHDHsWm5RREQ== X-Received: by 2002:ac8:6758:: with SMTP id n24mr29731870qtp.258.1607911438765; Sun, 13 Dec 2020 18:03:58 -0800 (PST) Received: from localhost ([2620:15c:6:411:cad3:ffff:feb3:bd59]) by smtp.gmail.com with ESMTPSA id g63sm13912475qkf.80.2020.12.13.18.03.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 13 Dec 2020 18:03:57 -0800 (PST) Date: Sun, 13 Dec 2020 21:03:56 -0500 From: Joel Fernandes To: Chinwen Chang Cc: Laurent Dufour , Haiyan Song , akpm@linux-foundation.org, mhocko@kernel.org, peterz@infradead.org, kirill@shutemov.name, ak@linux.intel.com, dave@stgolabs.net, jack@suse.cz, Matthew Wilcox , aneesh.kumar@linux.ibm.com, benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org, Thomas Gleixner , Ingo Molnar , hpa@zytor.com, Will Deacon , Sergey Senozhatsky , sergey.senozhatsky.work@gmail.com, Andrea Arcangeli , Alexei Starovoitov , kemi.wang@intel.com, Daniel Jordan , David Rientjes , Jerome Glisse , Ganesh Mahendran , Minchan Kim , Punit Agrawal , vinayak menon , Yang Shi , zhong jiang , Balbir Singh , sj38.park@gmail.com, Michel Lespinasse , Mike Rapoport , linux-kernel@vger.kernel.org, linux-mm@kvack.org, haren@linux.vnet.ibm.com, npiggin@gmail.com, paulmck@linux.vnet.ibm.com, Tim Chen , linuxppc-dev@lists.ozlabs.org, x86@kernel.org, miles.chen@mediatek.com Subject: Re: [PATCH v12 00/31] Speculative page faults Message-ID: References: <20190416134522.17540-1-ldufour@linux.ibm.com> <20190606065129.d5s3534p23twksgp@haiyan.sh.intel.com> <3d3cefa2-0ebb-e86d-b060-7ba67c48a59f@linux.ibm.com> <1c412ebe-c213-ee67-d261-c70ddcd34b79@linux.ibm.com> <20190620081945.hwj6ruqddefnxg6z@haiyan.sh.intel.com> <1594027500.30360.32.camel@mtkswgap22> <490c0811-50cd-0802-2cbc-9c031ef309f6@linux.ibm.com> <1594099897.30360.58.camel@mtkswgap22> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1594099897.30360.58.camel@mtkswgap22> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Jul 07, 2020 at 01:31:37PM +0800, Chinwen Chang wrote: [..] > > > Hi Laurent, > > > > > > We merged SPF v11 and some patches from v12 into our platforms. After > > > several experiments, we observed SPF has obvious improvements on the > > > launch time of applications, especially for those high-TLP ones, > > > > > > # launch time of applications(s): > > > > > > package version w/ SPF w/o SPF improve(%) > > > ------------------------------------------------------------------ > > > Baidu maps 10.13.3 0.887 0.98 9.49 > > > Taobao 8.4.0.35 1.227 1.293 5.10 > > > Meituan 9.12.401 1.107 1.543 28.26 > > > WeChat 7.0.3 2.353 2.68 12.20 > > > Honor of Kings 1.43.1.6 6.63 6.713 1.24 > > > > That's great news, thanks for reporting this! > > > > > > > > By the way, we have verified our platforms with those patches and > > > achieved the goal of mass production. > > > > Another good news! > > For my information, what is your targeted hardware? > > > > Cheers, > > Laurent. > > Hi Laurent, > > Our targeted hardware belongs to ARM64 multi-core series. Hello! I was trying to develop an intuition about why does SPF give improvement for you on small CPU systems. This is just a high-level theory but: 1. Assume the improvement is because of elimination of "blocking" on mmap_sem. Could it be that the mmap_sem is acquired in write-mode unnecessarily in some places, thus causing blocking on mmap_sem in other paths? If so, is it feasible to convert such usages to acquiring them in read-mode? 2. Assume the improvement is because of lesser read-side contention on mmap_sem. On small CPU systems, I would not expect reducing cache-line bouncing to give such a dramatic improvement in performance as you are seeing. Thanks for any insight on this! - Joel