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=-7.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_PASS,USER_AGENT_MUTT 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 07959C43381 for ; Tue, 19 Feb 2019 12:19:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B5329217D7 for ; Tue, 19 Feb 2019 12:19:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550578750; bh=rhp0tL21cRIxcBhxTt3aCrKDczKZ5oqAqZa92OHkjj4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=ErdYk8XehF5yBfoju5wHCCZyGSsufRcUnsMoVS91MjSH/Xqgl5pMDK5WQllD39BpF ML5HorTa9oHUdyUFkap+MWObns27/vlR9OQbnoM51CQRLi9NgZ+pwTIlllvT7ZjhLa uVldEy+NYyq9C/s0D37ZCUaRfPGTFoJIgXtkJRj0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727584AbfBSMTJ (ORCPT ); Tue, 19 Feb 2019 07:19:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:38072 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726141AbfBSMTI (ORCPT ); Tue, 19 Feb 2019 07:19:08 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D2C83217D7; Tue, 19 Feb 2019 12:19:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550578747; bh=rhp0tL21cRIxcBhxTt3aCrKDczKZ5oqAqZa92OHkjj4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hL41tv+/TVcEoLwqKKK3pNu4yVbAVS1sbASCeN10pANzTNZe9ynMthb4vNTja31fP EIVgjxn7YF+MaVB2b3l1UMxbPtTgo6N68P5UUPMXRdP01qmWu4B6G1tR+iaUogTy6v sMm5NtmnEj0rchITNWKqpLMxIJdKZyy6zlCWraLw= Date: Tue, 19 Feb 2019 13:19:04 +0100 From: Greg Kroah-Hartman To: Wei Yang Cc: kernel test robot , "Rafael J. Wysocki" , LKML , Stephen Rothwell , lkp@01.org Subject: Re: [LKP] [driver core] 570d020012: will-it-scale.per_thread_ops -12.2% regression Message-ID: <20190219121904.GA24103@kroah.com> References: <20190218075442.GI29177@shao2-debian> <20190219005945.GA16734@richard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190219005945.GA16734@richard> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 19, 2019 at 08:59:45AM +0800, Wei Yang wrote: > On Mon, Feb 18, 2019 at 03:54:42PM +0800, kernel test robot wrote: > >Greeting, > > > >FYI, we noticed a -12.2% regression of will-it-scale.per_thread_ops due to commit: > > > > > >commit: 570d0200123fb4f809aa2f6226e93a458d664d70 ("driver core: move device->knode_class to device_private") > >https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master > > > > This is interesting. > > I didn't expect the move of this field will impact the performance. > > The reason is struct device is a hotter memory than device->device_private? > > >in testcase: will-it-scale > >on test machine: 288 threads Knights Mill with 80G memory > >with following parameters: > > > > nr_task: 100% > > 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 > > > >In addition to that, the commit also has significant impact on the following tests: > > > >+------------------+---------------------------------------------------------------+ > >| testcase: change | will-it-scale: will-it-scale.per_thread_ops -29.9% regression | > >| test machine | 288 threads Knights Mill with 80G memory | > >| test parameters | cpufreq_governor=performance | > >| | mode=thread | > >| | nr_task=100% | > >| | test=signal1 | Ok, I'm going to blame your testing system, or something here, and not the above patch. All this test does is call raise(3). That does not touch the driver core at all. > >+------------------+---------------------------------------------------------------+ > >| testcase: change | will-it-scale: will-it-scale.per_thread_ops -16.5% regression | > >| test machine | 288 threads Knights Mill with 80G memory | > >| test parameters | cpufreq_governor=performance | > >| | mode=thread | > >| | nr_task=100% | > >| | test=open1 | > >+------------------+---------------------------------------------------------------+ Same here, open1 just calls open/close a lot. No driver core interaction at all there either. So are you _sure_ this is the offending patch? thanks, greg k-h