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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2B2A5C43334 for ; Thu, 16 Jun 2022 01:07:20 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 365876B0071; Wed, 15 Jun 2022 21:07:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3153C6B0072; Wed, 15 Jun 2022 21:07:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 18F388D0001; Wed, 15 Jun 2022 21:07:19 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 0B8616B0071 for ; Wed, 15 Jun 2022 21:07:19 -0400 (EDT) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id D51362128E for ; Thu, 16 Jun 2022 01:07:18 +0000 (UTC) X-FDA: 79582310556.17.3B03D00 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by imf04.hostedemail.com (Postfix) with ESMTP id 092A540092 for ; Thu, 16 Jun 2022 01:07:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1655341637; x=1686877637; h=message-id:date:subject:to:cc:references:from: in-reply-to:content-transfer-encoding:mime-version; bh=lmxdoKaO/0j/BFyGaSXW7oqNjlPRyBjuIC+8EEQba7M=; b=hqktBnXK6EVSq+lJ5ozsYe3lnZDMVQ1ZRFmcCBekkYttAB/0wdfN47it 0zx6CC1F/tgCQwZY2C6rJA0CcP6LUChH9mx/0jNNGT/lT7+VD5h2AQsLV Jhmq7acvS8Ru0Ajg65hBuy4ffx+sccK6xMWGuS2D11GeRhs01AJbeO+sN bnSP2KoclZhLaQWJA18OFOJM3qSkPFUC7/Gc71i4NpdCiAvaay3i8PYhw t0Ndeax+SsckNXlibqlqGIqZcG4LcPUZmVYlZ4RxOr1dux2EffhgcWmK+ lYB51SikceMEOrOK2Bfr4YhGc1c00lbSUvd70qWevne0ikMUtJ7OI1Lin A==; X-IronPort-AV: E=McAfee;i="6400,9594,10379"; a="258991688" X-IronPort-AV: E=Sophos;i="5.91,302,1647327600"; d="scan'208";a="258991688" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jun 2022 18:07:14 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.91,302,1647327600"; d="scan'208";a="583445564" Received: from fmsmsx606.amr.corp.intel.com ([10.18.126.86]) by orsmga007.jf.intel.com with ESMTP; 15 Jun 2022 18:07:13 -0700 Received: from fmsmsx608.amr.corp.intel.com (10.18.126.88) by fmsmsx606.amr.corp.intel.com (10.18.126.86) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.27; Wed, 15 Jun 2022 18:07:13 -0700 Received: from fmsmsx608.amr.corp.intel.com (10.18.126.88) by fmsmsx608.amr.corp.intel.com (10.18.126.88) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.27; Wed, 15 Jun 2022 18:07:12 -0700 Received: from fmsedg601.ED.cps.intel.com (10.1.192.135) by fmsmsx608.amr.corp.intel.com (10.18.126.88) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.27 via Frontend Transport; Wed, 15 Jun 2022 18:07:12 -0700 Received: from NAM04-MW2-obe.outbound.protection.outlook.com (104.47.73.176) by edgegateway.intel.com (192.55.55.70) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2308.27; Wed, 15 Jun 2022 18:07:12 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=H0a1vVAvgsczFSQiqUp355T/jS+ltn9ekqGjj5MduKOYc+UVGJLHkZdmQ1jB3XlYbwhD4VCQGkBb7bv1z0WH2juOTQcQq1hacOywGoDyrC42Csy2C1WIRsbnPdpEPmhklWWf+WbRjPGL4C6g8orDkZWM6YKFEo62/eC2sTfalsUEUOszZIVTX/YTNuatWNkqrCmxLNMGvG7Ekok3H9Ik0FXSm3gPGrfPl5XmdfT6TZmZp23u0bVW81hwId2WPsSjxxVpZEPi2fKnMCGDa7XN5Yg+FB7eCh8nJwVn1nhEDXkCDk8zfe4tlGIeQpmIAhnAr1OFpWTq4GViv0TWb9d/UQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=HoWNdAE01qhx3qCirCe4hqfd89qyY1monwCw1n0bC70=; b=WXdATXOD4bkRO1/lNEWY47QrnOtihg53/x60PQHCznM9OedYjQ+CqrkLuij9J7Z6kRGq3vniGXoof/dT4DviN4UVGPBAbMlTvfufed/1wvQLBqTBI0FD6AVyqmsjPngV1jB0bdOcpVvFgOEo7z79llNuxsSgnDXToAcbQx6/81BhN02xKYpaPIPwsFPCQUXkc3CHXfD1BgbXBylzks/QeWwOp75pUviLLLwblsTQyUqgMO+JQqnCq0zeCygchzAYMsTfaooqNNE158oHaKGCJnq+qrGQT5vkbvNKRk4EC8Z9v7pRhzbWQj4dhN9uwzoUhFXqHa2FiL72qXbLlW7XFQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Received: from CO1PR11MB4820.namprd11.prod.outlook.com (2603:10b6:303:6f::8) by CY4PR1101MB2358.namprd11.prod.outlook.com (2603:10b6:903:ba::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5332.14; Thu, 16 Jun 2022 01:07:11 +0000 Received: from CO1PR11MB4820.namprd11.prod.outlook.com ([fe80::39e0:6f4d:9c2a:85d9]) by CO1PR11MB4820.namprd11.prod.outlook.com ([fe80::39e0:6f4d:9c2a:85d9%9]) with mapi id 15.20.5353.014; Thu, 16 Jun 2022 01:07:11 +0000 Message-ID: <304d2dff-ef46-180e-0840-8c6480de1f06@intel.com> Date: Thu, 16 Jun 2022 09:07:03 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Firefox/91.0 Thunderbird/91.9.1 Subject: Re: [LKP] Re: [mm/readahead] 793917d997: fio.read_iops -18.8% regression Content-Language: en-US To: Matthew Wilcox CC: LKML , , , , References: <20220418144234.GD25584@xsang-OptiPlex-9020> <1e8deaea-5a05-1846-d51c-b834beb9f23e@intel.com> From: Yin Fengwei In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: SG2P153CA0010.APCP153.PROD.OUTLOOK.COM (2603:1096::20) To CO1PR11MB4820.namprd11.prod.outlook.com (2603:10b6:303:6f::8) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 3374133f-55e2-4ec9-5969-08da4f348ac3 X-MS-TrafficTypeDiagnostic: CY4PR1101MB2358:EE_ X-LD-Processed: 46c98d88-e344-4ed4-8496-4ed7712e255d,ExtAddr X-Microsoft-Antispam-PRVS: X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CO1PR11MB4820.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230016)(366004)(6666004)(31696002)(38100700002)(86362001)(8936002)(5660300002)(2616005)(31686004)(6486002)(508600001)(82960400001)(4326008)(66946007)(66476007)(8676002)(316002)(66556008)(36756003)(6916009)(2906002)(26005)(6506007)(186003)(53546011)(6512007)(45980500001)(43740500002);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?ay9VMVkvV2tFdmphUHBaYXBVZUl6VGs2US9OYnVtZnVMOWVqbDNDcHlzRC9o?= =?utf-8?B?UEk4bFBwNFpMMk9wcFI1ZUxZMHp1V3FjSzBkazU5KzZLdEJBTGFSZHZSQUlw?= =?utf-8?B?bGxEemkzMSs2NUF6U1FFaEdkZHl5djBPZUdGbVY1OHAxZ3d0TFVmRGJUVmxH?= =?utf-8?B?MHdoajY3K2RIZWpiWUlqT0FpeWtkaFdYZkhQRjYweFZ0djNaRVBvRjFLajRz?= =?utf-8?B?cHVxMlNKbEx5Rlg5R0ZiS3g0MmV0SDJURXR1NW5LTmNxS0NRSUFuRzNudFRH?= =?utf-8?B?RnN4L3AvVHJiWTdLNkozVUY2QmFzWlNxanNOMFgzSnVVb2l0NTd6QWtDS2Qz?= =?utf-8?B?amVtN1p1VTB0S1p6K1lGZTdSZTFqZ1ZFK2pTSjNaTHRlcFJTQ0xyWUdwYkZM?= =?utf-8?B?UkF2YkphTnk2bkdVUE1VYUZhdFgyRDBPYzZWNTVHaWEvRjJ4TFdObitVc1lL?= =?utf-8?B?ZTFkOGpVMEdHOCtib0s2bkErSE9nVEhsdUgzSFl6R0lRVllmM210TUpQSlE0?= =?utf-8?B?M0ZJc3F0RW9vOEVkVGoySXdLSzZvRVR2cFVqUVBZT1NOMHJkcGtmVzIvM1ZB?= =?utf-8?B?UDVvMUw5RmFmQTIxYmhrNFAzOGg1WE5vZ3pXazJya3d2eFp0MXZZd0tTUmMz?= =?utf-8?B?UTBxbDFwSExLUHV0OXJpSlRtTVhPQjBNL2lBVktmOHJRV0dRRjAyVFhteFIw?= =?utf-8?B?WTZDdWNPNDhoYjJsUkphY3lMMkxnZjV2T3c0S3k3Z3hHUHkwcGt2SkxDSFI3?= =?utf-8?B?WmNhZTB4UTFrcFZVdDRpVTcxT3lqRjB4bGFnc2ZMY3lSaGtaMmlTSGN0V1c0?= =?utf-8?B?UFNEc0hDZ055VytmeWVsNk5sWGtZa0t2RjRZeVo1cWxCZ1B3YTg0QXJ0ZEt5?= =?utf-8?B?U3BmbjU2S2ZaMVZCQVZUOGNFanMzS0hVeERoQS9jaXVzNzZFVm5adFoxWHlB?= =?utf-8?B?ZExmZnhoVDdnUWhIS2o3V0dSM044MDNOTVAxQy9EUWNFYW1WSjBjUDBUL3Qx?= =?utf-8?B?V3dsZ0xWNzcyNTN0dWR5RmFjbmpSUGR1d1lGbUZKQXc1cUxnbng2NmhGYWo0?= =?utf-8?B?dVBXVzc2ZWlMWVRoVm9YTEtuUi9YMnlaait3OFdBZ2xTaThxZXZTb0t6QUFR?= =?utf-8?B?NXJDUkllRm83Sm1Sa3ZGeURlZnQzQzBhRnZkS0JqN0ExNEduVWlRZDNJbUVw?= =?utf-8?B?L2pwc09GVTRmQzF2ak1xS1BVOEpvQ2d0T0hkY3JKdWtlbFFLd3JGeGpYTTdT?= =?utf-8?B?ckJBa1JmVWhEVEl1K0p6ZlZLY1M0eGZ4YWpRc1Nwd2tiMGxZblJiVDJ3dmt6?= =?utf-8?B?T0NmUUJ1and1NEF6bGM4Q0Rucktsajh3blQ1RzM3YmtCeFFEU04rZkcyY0xm?= =?utf-8?B?YktMOVhtRjZOK0h2bTBoS0JLT01haUZHMTkxQUJ6OXZMdFFQNk92b1c3bVJK?= =?utf-8?B?ZzV4UGN2Sm5EaEZicWpPNnhBNnRxK3U4b25rWkN5VEpNdUdMcFBHcW14ZTdz?= =?utf-8?B?MHd4cGxGdDhvbzhGS3A3UVRONktHRWt3ODNQbFVuR3dWdlBjVVVMNDdNZWQv?= =?utf-8?B?WGFiRm52SFh4RXNUcG9yS3Arb25kME1oQWlQa0NaZW42Mm5KemdvNTV4SFJs?= =?utf-8?B?bVlLNCtuekFDczlENHlpV0tDczlCcFh3RHR2bktGQTRCWWVzTDd1cUR2cEdy?= =?utf-8?B?cnFYeXNVcmFvUjl0MHZRVm5rM1J5Wm91dlN1a2VnRjI4Z3VHRnU5aW1MeGFI?= =?utf-8?B?R0MyMnJXNm9vaGZGendSbU1OZmRwVHZHd1g3N3djKzlyUlZWcnlFeFc5RmVR?= =?utf-8?B?UThZaTh2K0RXWFNZUkF4K2FMeFJwZDR5ZDRoRWxkWjRJVzJqaGhONCtsbmk5?= =?utf-8?B?Q2VFRGZHR0ptNm9jZDE4dUlQVUNHRUJQUVdGeHBKSElKVERzQkovb1lpQzIv?= =?utf-8?B?Yk9BdWlYRU9MbGNET2NCZVltaGs2RlJvNEZHSDllU0xBYVlCK3N0KzI4cE1I?= =?utf-8?B?YmtOUEVER0JCQy82MXQ5R1h3aGozelh1cHpFV1J5VFRFTmlHV3J6VitxMnk0?= =?utf-8?B?bHpLMlZxRnc3NFFtUGRKVyt3dFFQWTdIL3g5OFVSeS96ZDBKNmEzMFZYb1F4?= =?utf-8?B?MGdQMVZ1anJHVHNKbkRUbG00UENyckFIQUhDdjFUV3Bycm15VHVGUWxUbndv?= =?utf-8?B?LzFjRG5xTncwdGlITkhOMXRsRXpweTNWb1pNczRqV0IrWjhOWnVZZDY0OXNa?= =?utf-8?B?VUZNa2IrNFl3Nmo2OHBvYXZXM2dRVXN4T2FzYWVsSGdjaDVwWmlJYlBDWmtI?= =?utf-8?B?aUtuWVlhMGs0MlBKQ2IzNjlZcHZFQlI4Nkx1QnFYK1IzdXZmWHpwdm5MMmNU?= =?utf-8?Q?pVWbo9e4EnQMbqKo=3D?= X-MS-Exchange-CrossTenant-Network-Message-Id: 3374133f-55e2-4ec9-5969-08da4f348ac3 X-MS-Exchange-CrossTenant-AuthSource: CO1PR11MB4820.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Jun 2022 01:07:11.4401 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: BpWsLiuHWWVZx19gmD4EeFAglFwCrxP/VfoMNOztNIZNpsl7EePG8ez0HnWbbFNOau5/Fn9zeSZ6QjRHNH66Yw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR1101MB2358 X-OriginatorOrg: intel.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655341638; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=HoWNdAE01qhx3qCirCe4hqfd89qyY1monwCw1n0bC70=; b=7zpGf0++ZA4ufuFyBkHctMZlhRK3BMaQX25h/kQ0oorJqmF07pAa8gcyRF0AOna4rMWxZa ZMyGMGLzapt3oofvdOKYns47aGmaCCr5pgT5/AmdY/PUok64nxlgobe+d4iXbQK4AymHBA 6ZiLvNpA57HcWXWcc4YlTan6UtS1u2Q= ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1655341638; a=rsa-sha256; cv=fail; b=VA00pCBcvpHetj+rq/1FrfzPjuPrWGzDn+zHiAJd4IdT99K6qR3oKYe4XnjnYT4mxaiFcG ctlu8jC+f1VL7tPwk2jrAtzMDSVsew8dLlud0RkOKz/oT28Revuh9tjqixovhcOFiWmw7y hcq71kw3IbDS/HC3LTwhGTzMdX4ND7o= ARC-Authentication-Results: i=2; imf04.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=hqktBnXK; arc=reject ("signature check failed: fail, {[1] = sig:microsoft.com:reject}"); dmarc=pass (policy=none) header.from=intel.com; spf=none (imf04.hostedemail.com: domain of fengwei.yin@intel.com has no SPF policy when checking 192.55.52.136) smtp.mailfrom=fengwei.yin@intel.com Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=hqktBnXK; arc=reject ("signature check failed: fail, {[1] = sig:microsoft.com:reject}"); dmarc=pass (policy=none) header.from=intel.com; spf=none (imf04.hostedemail.com: domain of fengwei.yin@intel.com has no SPF policy when checking 192.55.52.136) smtp.mailfrom=fengwei.yin@intel.com X-Rspamd-Server: rspam12 X-Rspam-User: X-Stat-Signature: 87ghesaz76b5e8r5a9im3zkrwp4ct9mz X-Rspamd-Queue-Id: 092A540092 X-HE-Tag: 1655341636-468566 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 6/15/2022 8:36 PM, Matthew Wilcox wrote: > On Wed, Jun 15, 2022 at 02:38:24PM +0800, Yin Fengwei wrote: >> On 4/19/2022 1:08 AM, Matthew Wilcox wrote: >>> >>> I'm on holiday today, but adding linux-fsdevel and linux-mm so relevant >>> people know about this. >>> >>> Don't focus on the 18% regression, focus on the 240% improvement on the >>> other benchmark ;-) >>> >>> Seriously, someone (probably me) needs to dig into what the benchmark >>> is doing and understand whether there's a way to avoid (or decide this >>> regression isn't relevant) while keeping the performance gains elsewhere. >> With: >> commit b9ff43dd27434dbd850b908e2e0e1f6e794efd9b >> Author: Matthew Wilcox (Oracle) >> Date: Wed Apr 27 17:01:28 2022 -0400 >> >> mm/readahead: Fix readahead with large folios >> >> the regression is almost gone: > > That makes sense. I did think at the time that this was probably the > cause of the problem. > >> commit: >> 18788cfa236967741b83db1035ab24539e2a21bb >> b9ff43dd27434dbd850b908e2e0e1f6e794efd9b >> >> 18788cfa23696774 b9ff43dd27434dbd850b908e2e0 >> ---------------- --------------------------- >> fail:runs %reproduction fail:runs >> | | | >> 4698:9 -36360% 1426:3 dmesg.timestamp:last >> 3027:9 -22105% 1037:3 kmsg.timestamp:last >> %stddev %change %stddev >> \ | \ >> 0.39 ±253% -0.3 0.09 ±104% fio.latency_1000us% >> 0.00 ±141% +0.0 0.01 fio.latency_100ms% >> 56.60 ± 5% +10.3 66.92 ± 8% fio.latency_10ms% >> 15.65 ± 22% -1.3 14.39 ± 17% fio.latency_20ms% >> 1.46 ±106% -0.5 0.95 ± 72% fio.latency_2ms% >> 25.81 ± 25% -9.2 16.59 ± 18% fio.latency_4ms% >> 0.09 ± 44% +0.9 1.04 ± 22% fio.latency_50ms% >> 0.00 ±282% +0.0 0.02 ±141% fio.latency_750us% >> 13422 ± 6% -1.4% 13233 fio.read_bw_MBps <----- > > A stddev of 6% and a decline of 1.4%? How many tests did you run > to make sure that this is a real decline and not fluctuation of > one-quarter-of-one-standard-devisation? For this test case (fio-basic with the specific parameters), we ran it 9 times with commit 18788cfa236967741b83db1035ab24539e2a21bb and 3 times with commit b9ff43dd27434dbd850b908e2e0e1f6e794efd9b. The stddev for commit 18788cfa236967741b83db1035ab24539e2a21bb is 6%. The test result for commit b9ff43dd27434dbd850b908e2e0e1f6e794efd9b is quite stable. Its stddev is less than 1% so the value is not shown. Specific for -1.4%, we don't think it's real regression. As you said, it's less than stddev and we don't know whether it's because of stddev or not. The point here is the commit b9ff43dd27434dbd850b908e2e0e1f6e794efd9b could fix this regression. Thanks. Regards Yin, Fengwei > _______________________________________________ > LKP mailing list -- lkp@lists.01.org > To unsubscribe send an email to lkp-leave@lists.01.org