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 8749EC19F2D for ; Tue, 9 Aug 2022 14:17:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DC8468E0001; Tue, 9 Aug 2022 10:16:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D82836B0073; Tue, 9 Aug 2022 10:16:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C3EC98E0001; Tue, 9 Aug 2022 10:16:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id B1FE76B0072 for ; Tue, 9 Aug 2022 10:16:59 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 7F2D31A04AD for ; Tue, 9 Aug 2022 14:16:59 +0000 (UTC) X-FDA: 79780255758.19.1D0FF48 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by imf21.hostedemail.com (Postfix) with ESMTP id 469161C019D for ; Tue, 9 Aug 2022 14:16:58 +0000 (UTC) Received: from fraeml704-chm.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4M2FS53Ggzz67FSP; Tue, 9 Aug 2022 22:14:13 +0800 (CST) Received: from lhrpeml500003.china.huawei.com (7.191.162.67) by fraeml704-chm.china.huawei.com (10.206.15.53) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2375.24; Tue, 9 Aug 2022 16:16:55 +0200 Received: from [10.195.245.222] (10.195.245.222) by lhrpeml500003.china.huawei.com (7.191.162.67) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 9 Aug 2022 15:16:53 +0100 Message-ID: <16f03f81-a8c7-bacf-c74c-67231f7f7202@huawei.com> Date: Tue, 9 Aug 2022 15:16:52 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 Subject: Re: [ata] 0568e61225: stress-ng.copy-file.ops_per_sec -15.0% regression From: John Garry To: Damien Le Moal , kernel test robot CC: Christoph Hellwig , "Martin K. Petersen" , LKML , "Linux Memory Management List" , , , , , , , References: <1f498d4a-f93f-ceb4-b713-753196e5e08d@opensource.wdc.com> <3451fa5a-6229-073f-ae18-0c232cd48ed5@huawei.com> In-Reply-To: <3451fa5a-6229-073f-ae18-0c232cd48ed5@huawei.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.195.245.222] X-ClientProxiedBy: lhrpeml100006.china.huawei.com (7.191.160.224) To lhrpeml500003.china.huawei.com (7.191.162.67) X-CFilter-Loop: Reflected ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1660054618; a=rsa-sha256; cv=none; b=KkbxmgpzTSB5LPEZxg35oW2RSSU2W3kOplIgeWXze0IEKzQ3p61Gr/cdSM8+AeW2XQcGHj hdoz9WNp2FP68P9uPcJLxLTshRH1E9uq18Kesgnly0S1UUlBt5uEBI7F1pT/6ATJ+IabJ7 1PD6OsCwJ5YhlctcpRHLFu91yGSTkE0= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=none; spf=pass (imf21.hostedemail.com: domain of john.garry@huawei.com designates 185.176.79.56 as permitted sender) smtp.mailfrom=john.garry@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1660054618; 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; bh=ZGrIFVED/TLuRZMwz0ZRaKrPkheMey9Pcv6f8BZGvII=; b=Q11d1uY/TbRBDgMk+JyiQjuXV5z5T38bZDjeXdYdj89P+w29SDa6fNrC/3+Vfpn5O7ewsT ad8MOtqy52BbZLxckEEK0zebuixvuWAoR+dPVbUWeY9qOS2WAaKopIvZtGM+jvNnZvAv71 tSLV9toRSQs0PFfNMjkbj7ISRAsX1Yk= X-Rspamd-Server: rspam06 X-Rspam-User: X-Stat-Signature: z5eoimpm89mjfh9hntwmqmj74r7d6q3d X-Rspamd-Queue-Id: 469161C019D Authentication-Results: imf21.hostedemail.com; dkim=none; spf=pass (imf21.hostedemail.com: domain of john.garry@huawei.com designates 185.176.79.56 as permitted sender) smtp.mailfrom=john.garry@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-HE-Tag: 1660054618-902160 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 09/08/2022 10:58, John Garry wrote: >>> >>> commit: 0568e6122574dcc1aded2979cd0245038efe22b6 ("ata: libata-scsi: >>> cap ata_device->max_sectors according to shost->max_sectors") >>> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master >>> >>> in testcase: stress-ng >>> on test machine: 96 threads 2 sockets Ice Lake with 256G memory >>> with following parameters: >>> >>>     nr_threads: 10% >>>     disk: 1HDD >>>     testtime: 60s >>>     fs: f2fs >>>     class: filesystem >>>     test: copy-file >>>     cpufreq_governor: performance >>>     ucode: 0xb000280 >> >> Without knowing what the device adapter is, hard to say where the >> problem is. I >> suspect that with the patch applied, we may be ending up with a small >> default >> max_sectors value, causing overhead due to more commands than necessary. >> >> Will check what I see with my test rig. > > As far as I can see, this patch should not make a difference unless the > ATA shost driver is setting the max_sectors value unnecessarily low. For __ATA_BASE_SHT, we don't set max_sectors. As such, we default shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS (=1024) in scsi_host_alloc(). I assume no shost dma mapping limit applied. Then - for example - we could select dev->max_sectors = ATA_MAX_SECTORS_LBA48 (=65535) in ata_dev_configure(). So with commit 0568e6122574 we would have final max sectors = 1024, as opposed to 65535 previously. I guess that the problem is something like this. If so, it seems that we would need to apply the shost dma mapping limit separately in ata_scsi_dev_config() and not use shost->max_sectors. thanks, John