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=-0.8 required=3.0 tests=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 6AE13C5CFC0 for ; Mon, 18 Jun 2018 16:55:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3115A208B1 for ; Mon, 18 Jun 2018 16:55:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3115A208B1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.vnet.ibm.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 S1755368AbeFRQy7 (ORCPT ); Mon, 18 Jun 2018 12:54:59 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:56950 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S934623AbeFRQyy (ORCPT ); Mon, 18 Jun 2018 12:54:54 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w5IGnNJr057587 for ; Mon, 18 Jun 2018 12:54:53 -0400 Received: from e11.ny.us.ibm.com (e11.ny.us.ibm.com [129.33.205.201]) by mx0a-001b2d01.pphosted.com with ESMTP id 2jpg6xs4t6-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 18 Jun 2018 12:54:53 -0400 Received: from localhost by e11.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 18 Jun 2018 12:54:48 -0400 Received: from b01ledav003.gho.pok.ibm.com (b01ledav003.gho.pok.ibm.com [9.57.199.108]) by b01cxnp22035.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w5IGslQE10093260 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 18 Jun 2018 16:54:47 GMT Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 17A83B205F; Mon, 18 Jun 2018 12:54:38 -0400 (EDT) Received: from b01ledav003.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id ED4E8B2064; Mon, 18 Jun 2018 12:54:37 -0400 (EDT) Received: from paulmck-ThinkPad-W541 (unknown [9.70.82.159]) by b01ledav003.gho.pok.ibm.com (Postfix) with ESMTP; Mon, 18 Jun 2018 12:54:37 -0400 (EDT) Received: by paulmck-ThinkPad-W541 (Postfix, from userid 1000) id DEC2516C6AFC; Mon, 18 Jun 2018 09:56:46 -0700 (PDT) Date: Mon, 18 Jun 2018 09:56:46 -0700 From: "Paul E. McKenney" To: Joel Fernandes Cc: kernel test robot , Joel Fernandes , linux-kernel@vger.kernel.org, kernel-team@android.com, Josh Triplett , Lai Jiangshan , Mathieu Desnoyers , mingo@redhat.com, Steven Rostedt , tglx@linutronix.de, lkp@01.org Subject: Re: [lkp-robot] [rcutorture] 46e26223e3: WARNING:at_kernel/rcu/rcutorture.c:#rcu_torture_stats_print Reply-To: paulmck@linux.vnet.ibm.com References: <20180610234544.150933-2-joel@joelfernandes.org> <20180613065711.GZ16472@yexl-desktop> <20180613072948.GA142000@joelaf.mtv.corp.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180613072948.GA142000@joelaf.mtv.corp.google.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 18061816-2213-0000-0000-000002BBB3D2 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00009215; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000265; SDB=6.01048839; UDB=6.00537370; IPR=6.00827813; MB=3.00021721; MTD=3.00000008; XFM=3.00000015; UTC=2018-06-18 16:54:51 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18061816-2214-0000-0000-00005A8664E0 Message-Id: <20180618165646.GA3593@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-06-18_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1805220000 definitions=main-1806180195 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 13, 2018 at 12:29:48AM -0700, Joel Fernandes wrote: > (I'm actually not working this week, but still thought of replying :)) > > On Wed, Jun 13, 2018 at 02:57:11PM +0800, kernel test robot wrote: > > > > FYI, we noticed the following commit (built with gcc-4.9): > > > > commit: 46e26223e39c64763e321f229e324be15179c505 ("rcutorture: Make boost test more robust") > > url: https://github.com/0day-ci/linux/commits/Joel-Fernandes/rcutorture-Disable-RT-throttling-for-boost-tests/20180611-074731 > > base: https://git.kernel.org/cgit/linux/kernel/git/paulmck/linux-rcu.git rcu/next > > > > in testcase: trinity > > with following parameters: > > > > runtime: 300s > > > > test-description: Trinity is a linux system call fuzz tester. > > test-url: http://codemonkey.org.uk/projects/trinity/ > > I'll try to reproduce this, but it could be because after this patch, the > boost test is actually working. Quite possibly. ;-) > The reason for the rcutorture test failure could be that the default > kthread_prio for the system's RCU threads is set to 1 (unless overridden by > rcutree.kthread_prio) which is also equal to the priority of the rcutorture's > boost threads. Due to this the rcutorture test could starve the RCU threads > as well and defeat the boosting mechanism. I was able to solve a similar > issue by just passing rcutree.kthread_prio of 50 on the kernel command line. > > Paul, would it be ok if we changed the default kthread_prio to something > 1 > so that rcutorture can test properly without needing to pass any extra > rcutree.* parameters? > > so something like this in kernel/rcu/tree.c ? > > static int kthread_prio = IS_ENABLED(CONFIG_RCU_BOOST) ? 2 : 0; Would it be possible to also condition this on rcutorture being built in? Or are they doing modprobes for rcutorture? Thanx, Paul From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============8904474522904851264==" MIME-Version: 1.0 From: Paul E. McKenney To: lkp@lists.01.org Subject: Re: [lkp-robot] [rcutorture] 46e26223e3: WARNING:at_kernel/rcu/rcutorture.c:#rcu_torture_stats_print Date: Mon, 18 Jun 2018 09:56:46 -0700 Message-ID: <20180618165646.GA3593@linux.vnet.ibm.com> In-Reply-To: <20180613072948.GA142000@joelaf.mtv.corp.google.com> List-Id: --===============8904474522904851264== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On Wed, Jun 13, 2018 at 12:29:48AM -0700, Joel Fernandes wrote: > (I'm actually not working this week, but still thought of replying :)) > = > On Wed, Jun 13, 2018 at 02:57:11PM +0800, kernel test robot wrote: > > = > > FYI, we noticed the following commit (built with gcc-4.9): > > = > > commit: 46e26223e39c64763e321f229e324be15179c505 ("rcutorture: Make boo= st test more robust") > > url: https://github.com/0day-ci/linux/commits/Joel-Fernandes/rcutorture= -Disable-RT-throttling-for-boost-tests/20180611-074731 > > base: https://git.kernel.org/cgit/linux/kernel/git/paulmck/linux-rcu.gi= t rcu/next > > = > > in testcase: trinity > > with following parameters: > > = > > runtime: 300s > > = > > test-description: Trinity is a linux system call fuzz tester. > > test-url: http://codemonkey.org.uk/projects/trinity/ > = > I'll try to reproduce this, but it could be because after this patch, the > boost test is actually working. Quite possibly. ;-) > The reason for the rcutorture test failure could be that the default > kthread_prio for the system's RCU threads is set to 1 (unless overridden = by > rcutree.kthread_prio) which is also equal to the priority of the rcutortu= re's > boost threads. Due to this the rcutorture test could starve the RCU threa= ds > as well and defeat the boosting mechanism. I was able to solve a similar > issue by just passing rcutree.kthread_prio of 50 on the kernel command li= ne. > = > Paul, would it be ok if we changed the default kthread_prio to something = > 1 > so that rcutorture can test properly without needing to pass any extra > rcutree.* parameters? > = > so something like this in kernel/rcu/tree.c ? > = > static int kthread_prio =3D IS_ENABLED(CONFIG_RCU_BOOST) ? 2 : 0; Would it be possible to also condition this on rcutorture being built in? Or are they doing modprobes for rcutorture? Thanx, Paul --===============8904474522904851264==--