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=-3.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, URIBL_BLOCKED autolearn=ham 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 10326C0044C for ; Mon, 5 Nov 2018 17:11:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BD1A520862 for ; Mon, 5 Nov 2018 17:11:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=aol.com header.i=@aol.com header.b="WILf4Lmf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BD1A520862 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=aol.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730147AbeKFCcd (ORCPT ); Mon, 5 Nov 2018 21:32:33 -0500 Received: from sonic310-21.consmr.mail.gq1.yahoo.com ([98.137.69.147]:40009 "EHLO sonic310-21.consmr.mail.gq1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729733AbeKFCcd (ORCPT ); Mon, 5 Nov 2018 21:32:33 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=aol.com; s=a2048; t=1541437914; bh=M7IS0j1Q8QuVUGnbOGJMHaLTmRTKpPVAeyUIMzSZ4wE=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From:Subject; b=WILf4LmfSqTakzVTiQbh2pL7PxfjnnF+pmNdhaoND6pBUf6eWbSU/8WLwvPUNalGAZWyF9w5MlqqJqDrAaqBTINHejyeJz46feN1g9Vvb7Z5k/BBy+d1Dz/FX1hsgIPQh1MnHXjIKsbSDJz0Dy0zvaD68xmzZIlIAE7ZSam23qKvAL2QTEISxQRyQdxlwEjIC+YTk5yXQ12j1nJqBGat8Qqfj6D7/53IHNGr0T6uvQj9FaVhHm68uP1oNucU5/3B1YnDXNGZICM4kqzJfC+TzVSrpLUULiT83lGIL7pM0tiaqAZRdaOCvFfJX4Dr9Uz7qeE7IBZFvng3nA84XF0HZA== X-YMail-OSG: ywZl_uMVM1nq.zUX.xszdW_cGzzHRp3Afd9Dh1PNDo7JBim2DnvNYE4K214e8vc Yd0KTCfqjEVwl_KWtti.TYxLbaofgR8EvEbZewlbrFQHD3YtTc8pTAFYQgRGaD.80nx3rlv1yJWP i9CfEfe.2t1cOMQrgyEztDME5ApkNAgdAMbPSX4768adW42m8Q2u8kVJOmjiMIcudzPINAKrtwZ3 HrTzG8EOHBR8lINogI89gciYrHSRtwDBXQRKK661MHZpYmAMv0cHjvHW_JN9IUuAoWqvecH3aQi_ RssFO54KJnoQJyrBOkHnQYkqBBhhBmEW_BomKmxmB_jdLCVPCMc2RncHbY6Btu_moywm_GnEOYp0 2LTZd1DcHp4_UQ4L1poJ_Wf1fpdz9LCAJvFiGKBm.dpPdRbK.C3fO_x9UajFfFr9ap8Sd4PIWtE7 jflcerD0CpMMkfmJKHLn5aepYwRYvks.uHWVK3ThYmwEbVKg1SjNyknvgN0PBkqO9bxhn7F2_p.G yNzmA6hT.X_T8We2L6.QScZFmV7HW48CddgUiB61kTyh4rwX9zKevkr_lF9wX6ChFaW8Eyx.i8Dj uPz81CLgpQnaXtpfbGGx9VSTjI7IElHHPGv7hVFrDLRzXS_7zKsgqosNLF3hTiOeNsc1A4rK_oc9 BfDZbuFJkg2P.sS3TymoZy2ivcH3SKBfkE7jBV.SXnV7.9Z5faN0AHaglfVp4rVwrZQYWTA0R7gQ Pq7VV6EhKK_HE0ii9hjVAjTjxZTjhPKT7He8d3g77ICs55NV.lhIEgf5i8Ml3QKaBTCZFiOHrw.p 647uEj6CLsUCLBVlqUVb4dZAXzszUIglcuPJWVmW9.iHC.wKqDK6gcOHy6WZM4dqUafEillCZHFY np9x0fin4A_YG8gsk5Z7yCqBUQ7V1fz.BG1MxaLRyLgwDwxmAz8kPhyNYyRIQnQA3g2KCgw7XYW7 LGjoIHOIZavnV9aiZMzqhr85mjMUNIVuIJirfJEpElAfy6bPfBf2gyvz2AysYJ0EbPZzJXE34X_3 .6g3L8lZrnJ.PnQZ7CzjwXyTF0KSdqh.jUTB0DwLvRh4- Received: from sonic.gate.mail.ne1.yahoo.com by sonic310.consmr.mail.gq1.yahoo.com with HTTP; Mon, 5 Nov 2018 17:11:54 +0000 Received: from 60.177.33.247 (EHLO [192.168.199.149]) ([60.177.33.247]) by smtp432.mail.gq1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID 3a3443c36cf107c1ec063a51e3d2ba26; Mon, 05 Nov 2018 17:11:52 +0000 (UTC) Subject: Re: Re: [PATCH v2] bit_spinlock: introduce smp_cond_load_relaxed To: Gao Xiang , Greg Kroah-Hartman Cc: Philippe Ombredanne , Kate Stewart , Thomas Gleixner , Will Deacon , linux-kernel@vger.kernel.org, Peter Zijlstra , Miao Xie , Chao Yu References: <1539413249-4402-1-git-send-email-hsiangkao@aol.com> <20181030060441.16107-1-gaoxiang25@huawei.com> <3455f753-8f7c-91a8-c926-e06f5ed2d1bb@huawei.com> From: Gao Xiang Message-ID: Date: Tue, 6 Nov 2018 01:11:44 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <3455f753-8f7c-91a8-c926-e06f5ed2d1bb@huawei.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi all, ping... is there someone interested in this patch? It seems bit_spinlock performs much better by using smp_cond_load_relaxed than just do busy-loop in arm64... Thanks, Gao Xiang On 2018/10/30 13:52, Gao Xiang wrote: > Hi, > > On 2018/10/30 14:04, Gao Xiang wrote: >> It is better to use wrapped smp_cond_load_relaxed >> instead of open-coded busy waiting for bit_spinlock. >> >> Signed-off-by: Gao Xiang >> --- >> >> change log v2: >> - fix the incorrect expression !(VAL >> (bitnum & (BITS_PER_LONG-1))) >> - the test result is described in the following reply. >> >> Thanks, >> Gao Xiang > > > Simple test script: > #include > #include > #include > > unsigned long global_lock; > > int test_thread(void *data) > { > unsigned long thread_id = (unsigned long)data; > int i; > u64 start = ktime_get_ns(); > > for (i = 0; i < 500000; ++i) { > bit_spin_lock(0, &global_lock); > __asm__("yield"); > bit_spin_unlock(0, &global_lock); > } > pr_err("Thread id: %lu time: %llu\n", thread_id, ktime_get_ns() - start); > > do_exit(0); > } > > > static int __init bitspinlock_test_module_init(void) > { > int i; > > for (i = 0; i < 8; ++i) { > if (IS_ERR(kthread_run(test_thread, (void *)(unsigned long)i, "thread-%d", i))) > pr_err("fail to create thread %d\n", i); > } > > return 0; > } > > static void __exit bitspinlock_test_module_exit(void) > { > } > > module_init(bitspinlock_test_module_init); > module_exit(bitspinlock_test_module_exit); > MODULE_LICENSE("GPL"); > > > ...and tested in the following ARM server environment: > > Processor: HI1616 (https://en.wikichip.org/wiki/hisilicon/hi16xx/hi1616) > Board: HiSilicon D05 Development Board (http://open-estuary.org/d05/) > Memory: 512GB > Host OS: Ubuntu 18.04.1 LTS (Ubuntu 4.15.0-29.31-generic 4.15.18) > QEMU KVM OS: Linux 4.19 + buildroot > QEMU KVM cmdline: qemu-system-aarch64 -enable-kvm -cpu host -smp 4 -m 256M -kernel Image -M virt,kernel_irqchip=on -nographic -hda rootfs.ext2 -append 'root=/dev/vda console=ttyAMA0 earlycon=pl011,0x9000000' -serial mon:stdio -net none > > Without this patch: > Thread 0 Thread 1 Thread 2 Thread 3 Thread 4 Thread 5 Thread 6 Thread 7 > 1 1283709480 1271869280 454742480 1173673820 1145643640 1118846920 774616920 1144146140 > 2 643580180 625143860 576841700 322982340 649987880 585749000 529178880 373374780 > 3 672307220 847315000 880801860 1039502040 667086380 1033939940 1035381120 1046898300 > 4 568635580 440547020 737000380 910040880 804543740 712314280 868896880 867049000 > 5 749107320 726397720 776134480 611970100 756721040 753449440 711691300 609343300 > > With this patch: > Thread 0 Thread 1 Thread 2 Thread 3 Thread 4 Thread 5 Thread 6 Thread 7 > 1 170327620 196322160 169434180 74723860 178145600 178873460 143843260 70998780 > 2 166415220 129649200 166161240 175241520 155474460 112811860 157003140 150087420 > 3 511420780 117655640 598641860 596213720 462888760 430838600 554346300 428035120 > 4 174520240 156311800 120274280 87465380 172781400 136118620 163728340 63026360 > 5 153677940 202786860 183626500 140721300 150311360 161266840 168154340 107247460 > > Thanks, > Gao Xiang >