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=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY autolearn=no 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 1C367C433C1 for ; Mon, 22 Mar 2021 23:51:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E6776619A5 for ; Mon, 22 Mar 2021 23:51:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230009AbhCVXuj (ORCPT ); Mon, 22 Mar 2021 19:50:39 -0400 Received: from aserp2130.oracle.com ([141.146.126.79]:39760 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230401AbhCVXud (ORCPT ); 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Mon, 22 Mar 2021 23:50:01 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 12MNkJ5M153839; Mon, 22 Mar 2021 23:50:00 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3020.oracle.com with ESMTP id 37dtxxja7t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 22 Mar 2021 23:50:00 +0000 Received: from abhmp0002.oracle.com (abhmp0002.oracle.com [141.146.116.8]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 12MNnmV2030006; Mon, 22 Mar 2021 23:49:52 GMT Received: from dhcp-10-39-195-110.vpn.oracle.com (/10.39.195.110) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 22 Mar 2021 23:49:48 +0000 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 13.4 \(3608.120.23.2.4\)) Subject: Re: [External] : Re: [LKP] Re: [locking/qspinlock] 0e8d8f4f12: stress-ng.zero.ops_per_sec -9.7% regression From: Alex Kogan In-Reply-To: Date: Mon, 22 Mar 2021 19:49:46 -0400 Cc: kernel test robot , 0day robot , Steven Sistare , Waiman Long , LKML , "lkp@lists.01.org" , "linux@armlinux.org.uk" , "peterz@infradead.org" , "mingo@redhat.com" , "will.deacon@arm.com" , "arnd@arndb.de" , "linux-arch@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "tglx@linutronix.de" , "bp@alien8.de" , "hpa@zytor.com" , "x86@kernel.org" , "guohanjun@huawei.com" , "jglauber@marvell.com" , Daniel Jordan , Dave Dice Content-Transfer-Encoding: quoted-printable Message-Id: <90FEBB90-F136-4692-8102-9C21367D34B9@oracle.com> References: <20201223054455.1990884-4-alex.kogan@oracle.com> <20201228081601.GA31221@xsang-OptiPlex-9020> <503790ff-7f97-a3d3-8780-6ebb234efde1@linux.intel.com> To: Xing Zhengjun X-Mailer: Apple Mail (2.3608.120.23.2.4) X-Proofpoint-IMR: 1 X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=9931 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 mlxlogscore=999 malwarescore=0 phishscore=0 bulkscore=0 mlxscore=0 suspectscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2103220177 X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=9931 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 phishscore=0 lowpriorityscore=0 suspectscore=0 clxscore=1015 priorityscore=1501 spamscore=0 adultscore=0 impostorscore=0 mlxlogscore=999 mlxscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2103220177 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Mar 22, 2021, at 7:15 PM, Alex Kogan wrote: >=20 > Many thanks to Zhengjun Xing for the help in reproducing the issue. >=20 > On our system, the regression is less than 7% (the numbers are below), = however, > at least at the full capacity, the numbers are very stable. This = allowed me to track down the > issue and identify unnecessary stores into the queue node structure, = which may cause=20 > cache misses during lock transfers. Moving those stores into the = initialization code (cna_init_nodes()) > solves the problem. >=20 > Below are the numbers of =E2=80=9Cbogo ops/s=E2=80=9D reported by = stress-ng with various numbers of workers.=20 > Each number represents an average over 25 runs, with the standard = deviation reported in (). >=20 > #workers stock CNA / speedup = CNA+patch / speedup > 18 16327.844 (581.744) 15480.061 (582.654) / 0.948 16422.349 = (473.729) / 1.006 > 36 8573.557 (285.058) 8003.888 (196.125) / 0.934 8457.436 = (258.065) / 0.986 > 72 4042.535 (28.766) 3960.407 (28.648) / 0.980 4107.143 = (23.037) / 1.016 > 108 2735.913 (7.440) 2678.888 (7.102) / 0.979 2774.751 = (4.375) / 1.014 > 144 2093.477 (3.341) 2042.968 (1.982) / 0.976 2109.879 = (1.714) / 1.008 Those are "bogo ops/s (usr+sys time)", btw. Just in case, below are = "bogo ops/s (real time)=E2=80=9D numbers, which I believe is what is reported by the kernel test robot: #workers stock CNA / speedup = CNA+patch / speedup 18 262932.282 (12638.248) 249653.081 (11822.940) / 0.949 = 265189.104 (9271.447) / 1.009 36 277315.640 (11100.324) 260177.335 (7186.451) / 0.938 = 274691.250 (10329.523) / 0.991 72 263904.000 (2128.206) 259967.180 (1857.393) / 0.985 = 268971.483 (1713.639) / 1.019 108 273811.373 (664.517) 268949.947 (690.329) / 0.982 = 278196.867 (403.978) / 1.016 144 284321.364 (399.281) 278153.208 (210.776) / 0.978 = 287343.806 (280.963) / 1.011 Regards, =E2=80=94 Alex > The patch is attached. As always, comments are welcome! >=20 > Unless there any objections, I will reintegrate the patch into the = series, and post a new > revision. >=20 > Regards, > =E2=80=94 Alex