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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 568B1C25B06 for ; Wed, 10 Aug 2022 08:33:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231203AbiHJIdj (ORCPT ); Wed, 10 Aug 2022 04:33:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58902 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230035AbiHJIda (ORCPT ); Wed, 10 Aug 2022 04:33:30 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60C8557250; Wed, 10 Aug 2022 01:33:29 -0700 (PDT) Received: from fraeml701-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4M2jrM3KsSz67Xgw; Wed, 10 Aug 2022 16:33:23 +0800 (CST) Received: from lhrpeml500003.china.huawei.com (7.191.162.67) by fraeml701-chm.china.huawei.com (10.206.15.50) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2375.24; Wed, 10 Aug 2022 10:33:27 +0200 Received: from [10.195.247.138] (10.195.247.138) 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; Wed, 10 Aug 2022 09:33:24 +0100 Message-ID: <82dbf4d6-2d43-20ff-22a7-857f9f11a5ce@huawei.com> Date: Wed, 10 Aug 2022 09:33:23 +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 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> <16f03f81-a8c7-bacf-c74c-67231f7f7202@huawei.com> From: John Garry In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.195.247.138] X-ClientProxiedBy: lhrpeml500005.china.huawei.com (7.191.163.240) To lhrpeml500003.china.huawei.com (7.191.162.67) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-ide@vger.kernel.org On 09/08/2022 15:57, Damien Le Moal wrote: >>> 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. > OK. Will have a look at that. > We may need to introduce something like shost->max_hw_sectors, which is set according to sht max sectors and dma mapping limits. That could be also used in USB scsiglue slave_configure() Or else set max_sectors value for __ATA_BASE_SHT, but I don't know a sane value there considering ATA_MAX_SECTORS_LBA48 gives max_sectors of 65535. Damien, please let me know if you need help now. I am just waiting for you to test to prove this theory about dev->max_sectors being capped. I don't have an AHCI setup readily-available for testing - just SAS cards or QEMU. Thanks, John From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============3370099377810384930==" MIME-Version: 1.0 From: John Garry To: lkp@lists.01.org Subject: Re: [ata] 0568e61225: stress-ng.copy-file.ops_per_sec -15.0% regression Date: Wed, 10 Aug 2022 09:33:23 +0100 Message-ID: <82dbf4d6-2d43-20ff-22a7-857f9f11a5ce@huawei.com> In-Reply-To: List-Id: --===============3370099377810384930== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On 09/08/2022 15:57, Damien Le Moal wrote: >>> 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 =3D SCSI_DEFAULT_MAX_SECTORS (=3D1024) in >> scsi_host_alloc(). I assume no shost dma mapping limit applied. >> >> Then - for example - we could select dev->max_sectors =3D >> ATA_MAX_SECTORS_LBA48 (=3D65535) in ata_dev_configure(). >> >> So with commit 0568e6122574 we would have final max sectors =3D 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. > OK. Will have a look at that. > = We may need to introduce something like shost->max_hw_sectors, which is = set according to sht max sectors and dma mapping limits. That could be = also used in USB scsiglue slave_configure() Or else set max_sectors value for __ATA_BASE_SHT, but I don't know a = sane value there considering ATA_MAX_SECTORS_LBA48 gives max_sectors of = 65535. Damien, please let me know if you need help now. I am just waiting for = you to test to prove this theory about dev->max_sectors being capped. I = don't have an AHCI setup readily-available for testing - just SAS cards = or QEMU. Thanks, John --===============3370099377810384930==--