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=-7.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 04E7FC433E1 for ; Thu, 11 Jun 2020 02:07:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DC6CB207ED for ; Thu, 11 Jun 2020 02:07:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726407AbgFKCHd (ORCPT ); Wed, 10 Jun 2020 22:07:33 -0400 Received: from mga02.intel.com ([134.134.136.20]:18297 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726265AbgFKCHc (ORCPT ); Wed, 10 Jun 2020 22:07:32 -0400 IronPort-SDR: MM2iTVu7nZ5lej1oVUpCCr8KyskROO1SZFCSwxBudqgb72LN7CHCLu9g5+7d/8JUI9NzvppZeK 4rAJ8rBr/g6w== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Jun 2020 19:07:32 -0700 IronPort-SDR: /Ge1PVEpVrBbA2100P3pQNHJyfAEGcrkEFRiCLJorfdprEtApfcMvqffyphjlsELMvbEEkWC1y HMDXYRYgadTA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,498,1583222400"; d="scan'208";a="275176620" Received: from shao2-debian.sh.intel.com (HELO localhost) ([10.239.13.3]) by orsmga006.jf.intel.com with ESMTP; 10 Jun 2020 19:07:26 -0700 Date: Thu, 11 Jun 2020 10:06:57 +0800 From: kernel test robot To: Ian Kent Cc: Greg Kroah-Hartman , Andrew Morton , Al Viro , Tejun Heo , Rick Lindsley , Stephen Rothwell , David Howells , Miklos Szeredi , linux-fsdevel , Kernel Mailing List , lkp@lists.01.org Subject: Re: [kernfs] ea7c5fc39a: stress-ng.stream.ops_per_sec 11827.2% improvement Message-ID: <20200611020657.GI12456@shao2-debian> References: <159038562460.276051.5267555021380171295.stgit@mickey.themaw.net> <20200606155216.GU12456@shao2-debian> <20200606181802.GA15638@kroah.com> <5df6bec6f1b332c993474782c08fe8db30bffddc.camel@themaw.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <5df6bec6f1b332c993474782c08fe8db30bffddc.camel@themaw.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Sun, Jun 07, 2020 at 09:13:08AM +0800, Ian Kent wrote: > On Sat, 2020-06-06 at 20:18 +0200, Greg Kroah-Hartman wrote: > > On Sat, Jun 06, 2020 at 11:52:16PM +0800, kernel test robot wrote: > > > Greeting, > > > > > > FYI, we noticed a 11827.2% improvement of stress- > > > ng.stream.ops_per_sec due to commit: > > > > > > > > > commit: ea7c5fc39ab005b501e0c7666c29db36321e4f74 ("[PATCH 1/4] > > > kernfs: switch kernfs to use an rwsem") > > > url: > > > https://github.com/0day-ci/linux/commits/Ian-Kent/kernfs-proposed-locking-and-concurrency-improvement/20200525-134849 > > > > > > > Seriously? That's a huge performance increase, and one that feels > > really odd. Why would a stress-ng test be touching sysfs? > > That is unusually high even if there's a lot of sysfs or kernfs > activity and that patch shouldn't improve VFS path walk contention > very much even if it is present. > > Maybe I've missed something, and the information provided doesn't > seem to be quite enough to even make a start on it. > > That's going to need some analysis which, for my part, will need to > wait probably until around rc1 time frame to allow me to get through > the push down stack (reactive, postponed due to other priorities) of > jobs I have in order to get back to the fifo queue (longer term tasks, > of which this is one) list of jobs I need to do as well, ;) > > Please, kernel test robot, more information about this test and what > it's doing. > Hi Ian, We increased the timeout of stress-ng from 1s to 32s, and there's only 3% improvement of stress-ng.stream.ops_per_sec: fefcfc968723caf9 ea7c5fc39ab005b501e0c7666c testcase/testparams/testbox ---------------- -------------------------- --------------------------- %stddev change %stddev \ | \ 10686 3% 11037 stress-ng/cpu-cache-performance-1HDD-100%-32s-ucode=0x500002c/lkp-csl-2sp5 10686 3% 11037 GEO-MEAN stress-ng.stream.ops_per_sec It seems the result of stress-ng is inaccurate if test time too short, we'll increase the test time to avoid unreasonable results, sorry for the inconvenience. Best Regards, Rong Chen