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 10DE2C25B0F for ; Sat, 13 Aug 2022 07:23:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234125AbiHMHXo (ORCPT ); Sat, 13 Aug 2022 03:23:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45912 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233812AbiHMHXo (ORCPT ); Sat, 13 Aug 2022 03:23:44 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F3E836FA11; Sat, 13 Aug 2022 00:23:39 -0700 (PDT) Received: from fraeml705-chm.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4M4X350TN8z67TNp; Sat, 13 Aug 2022 15:18:57 +0800 (CST) Received: from lhrpeml500003.china.huawei.com (7.191.162.67) by fraeml705-chm.china.huawei.com (10.206.15.54) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2375.24; Sat, 13 Aug 2022 09:23:37 +0200 Received: from [10.48.145.22] (10.48.145.22) 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; Sat, 13 Aug 2022 08:23:36 +0100 Message-ID: <2b900d3b-9b52-5bc3-4ba8-24249f3c2e42@huawei.com> Date: Sat, 13 Aug 2022 08:23:36 +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 , Oliver Sang 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> <2e9cf5a6-c043-5ccf-e363-097c6c941891@huawei.com> <4642848c-a386-d6a0-6255-8b16800e0548@opensource.wdc.com> <840a5f98-a53c-ce08-2833-f41d8c9a015b@opensource.wdc.com> From: John Garry In-Reply-To: <840a5f98-a53c-ce08-2833-f41d8c9a015b@opensource.wdc.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.48.145.22] X-ClientProxiedBy: lhrpeml100001.china.huawei.com (7.191.160.183) 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 12/08/2022 19:27, Damien Le Moal wrote: >> Interestingly ata dev max_sectors kb also gets capped from 32MB (LBA48) >> -> 256KB due to swiotlb max mapping size. (It would be capped by shost >> default max sectors 512KB without that swiotlb limit). I assume capping >> due to swiotlb limit is not occuring on Oliver's machine. > Yes, I was suspecting that we may be seeing a difference for anything that is > not AHCI, e.g. with other drivers. > > But that seems to be the correct thing to do, no ? Yes, this should be the correct thing to do. > How was this working before > without applying the swiotlb limit ? > Not sure. I would need to check the libata code for how it handles DMA mapping errors, which I assume would occur for when we exceed the swiotlb limit. Having said this, from limited testing, whenever I check megaraid sas or mpt3sas for performance, the length of request data never/rarely comes close to max sectors. That why I am surprised with the regression which Oliver reports. Thanks, John From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============4878315860925234326==" 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: Sat, 13 Aug 2022 08:23:36 +0100 Message-ID: <2b900d3b-9b52-5bc3-4ba8-24249f3c2e42@huawei.com> In-Reply-To: <840a5f98-a53c-ce08-2833-f41d8c9a015b@opensource.wdc.com> List-Id: --===============4878315860925234326== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On 12/08/2022 19:27, Damien Le Moal wrote: >> Interestingly ata dev max_sectors kb also gets capped from 32MB (LBA48) >> -> 256KB due to swiotlb max mapping size. (It would be capped by shost >> default max sectors 512KB without that swiotlb limit). I assume capping >> due to swiotlb limit is not occuring on Oliver's machine. > Yes, I was suspecting that we may be seeing a difference for anything tha= t is > not AHCI, e.g. with other drivers. > = > But that seems to be the correct thing to do, no ? = Yes, this should be the correct thing to do. > How was this working before > without applying the swiotlb limit ? > Not sure. I would need to check the libata code for how it handles DMA = mapping errors, which I assume would occur for when we exceed the = swiotlb limit. Having said this, from limited testing, whenever I check megaraid sas or = mpt3sas for performance, the length of request data never/rarely comes = close to max sectors. That why I am surprised with the regression which = Oliver reports. Thanks, John --===============4878315860925234326==--