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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 B485AC004D2 for ; Sun, 30 Sep 2018 09:01:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 60E732082A for ; Sun, 30 Sep 2018 09:01:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="dwuFkoX8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 60E732082A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.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 S1727992AbeI3PdI (ORCPT ); Sun, 30 Sep 2018 11:33:08 -0400 Received: from mail-yb1-f193.google.com ([209.85.219.193]:42482 "EHLO mail-yb1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727862AbeI3PdH (ORCPT ); Sun, 30 Sep 2018 11:33:07 -0400 Received: by mail-yb1-f193.google.com with SMTP id p74-v6so4415244ybc.9 for ; Sun, 30 Sep 2018 02:00:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dp1EPl6E1YaA9KJlXMxFyYBiqqHx1DOzErCtNm3n3jk=; b=dwuFkoX8IHszyH6aPIjl/RJ06nEhgEtEpqM2jK9acBwmKNXHuqch3qzsteuZFU79DY TQoXZ8WPH6ZsRi2MZRzcxcYqoWtQimr2xtrCZev2QXJvvijVPCq2haBqDjJw3xuPdCX3 DekyRE6cNX/Bwv84tCd7g5//+ZG3tCRSCjqqcwFivMcF0lfg4XFtbQz0fmaXDLQmswyx sWO6G2BrYZNapKTCVg8RW2Yk6IRvwi4zh3MWO3aMWnWqe6R7jbcP9zmbGQL0N2bDLV4M 7BSth2BQlPHwKQB2JUGmiYI+h//vyvfM7/quToWm3EjMgMaWUmfHy1HJBS9HblacNxSm Glvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=dp1EPl6E1YaA9KJlXMxFyYBiqqHx1DOzErCtNm3n3jk=; b=o+H3wHy/nsOltb+hhR15gR1zrgVO07xWwOiXnVkoSKWlGzORsSQI+OTKTxWnwp6z2x RlHztqrsadRCduW2OCVTjzJ346lFsaFri8D23fpuhFXbUNDiRlQcMIM5uu+Ubn2+K/dd v3XWCCkT1b+mdOa7Pr7QP6ZAxfvBIIZ4qTSPw9lfZVdKMWc3DYHukUsGz6T9uPr/bcu3 B/SixR3hUT2KWh+hw53Rq8DrIRgGXNhfYQM8pP44F46qUDoRKzpGbVvv6I3/8cAIQ8tl EiCWYsDGmhNLvLP7sTOBG+stt8I5NGdmWy8T5u9hEvEuiPzwOrNmY2nUR3A4DQiKffrz QCGg== X-Gm-Message-State: ABuFfogjC6kKZXadz25mkgaBfjnJKFea1pwxRmqYTzG6LaOdMFRcD/2k jPgoIQhsxT1P0aTdKiBoHWbhF6mx7MthpCspDGnE5qqX X-Google-Smtp-Source: ACcGV62GEGSE0L9KfG08pio5maHGBAYhMmpTlV655PPRVe4G8K1vFYgNyHy9tmnlwbUnY9IrqUl795lfrE5t1q2j4+8= X-Received: by 2002:a25:2ad1:: with SMTP id q200-v6mr3184399ybq.462.1538298058330; Sun, 30 Sep 2018 02:00:58 -0700 (PDT) MIME-Version: 1.0 References: <20180930065100.GL15893@shao2-debian> In-Reply-To: <20180930065100.GL15893@shao2-debian> From: Amir Goldstein Date: Sun, 30 Sep 2018 12:00:46 +0300 Message-ID: Subject: Re: [LKP] [fsnotify] 60f7ed8c7c: will-it-scale.per_thread_ops -5.9% regression To: rong.a.chen@intel.com Cc: Jan Kara , linux-kernel , Stephen Rothwell , LKP Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Sep 30, 2018 at 9:50 AM kernel test robot wrote: > > Greeting, > > FYI, we noticed a -5.9% regression of will-it-scale.per_thread_ops due to commit: > > > commit: 60f7ed8c7c4d06aeda448c6da74621552ee739aa ("fsnotify: send path type events to group with super block marks") > https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master > > in testcase: will-it-scale > on test machine: 88 threads Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz with 64G memory > with following parameters: > > nr_task: 16 > mode: thread > test: unlink2 > cpufreq_governor: performance > > test-description: Will It Scale takes a testcase and runs it from 1 through to n parallel copies to see if the testcase will scale. It builds both a process and threads based test in order to see any differences between the two. > test-url: https://github.com/antonblanchard/will-it-scale > > > > Details are as below: > --------------------------------------------------------------------------------------------------> > > > To reproduce: > > git clone https://github.com/intel/lkp-tests.git > cd lkp-tests > bin/lkp install job.yaml # job file is attached in this email > bin/lkp run job.yaml > > ========================================================================================= > compiler/cpufreq_governor/kconfig/mode/nr_task/rootfs/tbox_group/test/testcase: > gcc-7/performance/x86_64-rhel-7.2/thread/16/debian-x86_64-2018-04-03.cgz/lkp-bdw-ep3d/unlink2/will-it-scale > > commit: > 1e6cb72399 ("fsnotify: add super block object type") > 60f7ed8c7c ("fsnotify: send path type events to group with super block marks") > I have to admit this looks strange. All this commit does is dereference mnt->mnt.mnt_sb and then sb->s_fsnotify_mask/sb->s_fsnotify_marks to find that they are zero. AFAICT there should be no extra contention added by this commit and it's hard to believe that parallel unlink workload would suffer from this change. I will try to install lkp-tests to verify this on my own system, but until proven otherwise I will regard this as false positive. Thanks, Amir.