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[2620:137:e000::1:20]) by mx.google.com with ESMTP id b8-20020a631b48000000b003644cfa0dd2si1445766pgm.141.2022.03.03.00.49.15; Thu, 03 Mar 2022 00:49:33 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@intel.com header.s=Intel header.b=Z4mgowcg; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231328AbiCCIoK (ORCPT + 99 others); Thu, 3 Mar 2022 03:44:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34246 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229741AbiCCIoK (ORCPT ); Thu, 3 Mar 2022 03:44:10 -0500 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 440144476F for ; Thu, 3 Mar 2022 00:43:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1646297005; x=1677833005; h=from:to:cc:subject:references:date:in-reply-to: message-id:mime-version; bh=SHdyf+PKhNOcM/g/UzBGMpH6cSN4pJToBy0ZwbC6omc=; b=Z4mgowcgDSTcEYZ9goxNuhRUBjU90TJiLhTzARI2uFinQVRXCmCXWZrq ohMEsrF/P//ninyzMAqpR+b20QeHdK0Wqd1LmM7nlS6gDbVrtTVYF2VTt 8gDsHLfZR5jiCCib59qbwpBNJMeaeilgK2wI9wwK/SWCLdIGbvB9Oistj nFWUGZfUjj1Bl7syTAgGgG2lfyrY2XmmdvmEE0+qEMjaLkWK/U1LS1tah B2BBhizvICX+JpDdZYh8VMywGJMciMVurERS8IRVvH6pXL4T+SIsxt995 K9UU5ZGodo3xX3xlOsNkBAFlrXb/OAxfFulwNmNLvTA69NJTRKDXHUdKz w==; X-IronPort-AV: E=McAfee;i="6200,9189,10274"; a="316836438" X-IronPort-AV: E=Sophos;i="5.90,151,1643702400"; d="scan'208";a="316836438" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Mar 2022 00:43:24 -0800 X-IronPort-AV: E=Sophos;i="5.90,151,1643702400"; d="scan'208";a="535739738" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.239.13.11]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Mar 2022 00:43:22 -0800 From: "Huang, Ying" To: kernel test robot Cc: Peter Zijlstra , LKML , , , , , , , , Subject: Re: [sched/numa] 0fb3978b0a: stress-ng.fstat.ops_per_sec -18.9% regression References: <20220302140220.GA32817@xsang-OptiPlex-9020> Date: Thu, 03 Mar 2022 16:43:20 +0800 In-Reply-To: <20220302140220.GA32817@xsang-OptiPlex-9020> (kernel test robot's message of "Wed, 2 Mar 2022 22:02:21 +0800") Message-ID: <87mti7s9xz.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Spam-Status: No, score=-4.8 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Oliver, Thanks for report. I still cannot connect the regression with the patch yet. To double check, I have run test again with "sched_verbose" kernel command line, and verified that the sched_domain isn't changed at all with the patch. kernel test robot writes: > 0.11 6% +0.1 0.16 4% perf-profile.self.cycles-pp.update_rq_clock > 0.00 +0.1 0.06 6% perf-profile.self.cycles-pp.memset_erms > 0.00 +0.1 0.07 5% perf-profile.self.cycles-pp.get_pid_task > 0.06 7% +0.1 0.17 6% perf-profile.self.cycles-pp.select_task_rq_fair > 0.54 5% +0.1 0.68 perf-profile.self.cycles-pp.lockref_put_return > 4.26 +1.1 5.33 perf-profile.self.cycles-pp.common_perm_cond > 15.45 +4.9 20.37 perf-profile.self.cycles-pp.lockref_put_or_lock > 20.12 +6.7 26.82 perf-profile.self.cycles-pp.lockref_get_not_dead From the perf-profile above, the most visible change is more cycles in lockref_get_not_dead(), which will loop with cmpxchg on dentry->d_lockref. So this appears to be related to the memory layout. I will try to debug that. Because stress-ng is a weird "benchmark" although it's a very good functionality test, and I cannot connect the patch with the test case and performance metrics collected. I think this regression should be a low priority one which shouldn't prevent the merging etc. But I will continue to investigate the regression to try to root cause it. Best Regards, Huang, Ying