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 smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 65C57CCA473 for ; Thu, 9 Jun 2022 17:54:12 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id 170458402F; Thu, 9 Jun 2022 17:54:12 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id KsuYDdJ7j1Ok; Thu, 9 Jun 2022 17:54:11 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp1.osuosl.org (Postfix) with ESMTPS id 08CDB84000; Thu, 9 Jun 2022 17:54:11 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id E17ABC0032; Thu, 9 Jun 2022 17:54:10 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 3592CC002D for ; Thu, 9 Jun 2022 17:54:09 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 15A024152D for ; Thu, 9 Jun 2022 17:54:09 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 3mMp68UYLZhL for ; Thu, 9 Jun 2022 17:54:07 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by smtp4.osuosl.org (Postfix) with ESMTPS id 6108F41906 for ; Thu, 9 Jun 2022 17:54:07 +0000 (UTC) Received: from fraeml715-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4LJs7n4GZKz67xjL; Fri, 10 Jun 2022 01:50:29 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml715-chm.china.huawei.com (10.206.15.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 9 Jun 2022 19:54:03 +0200 Received: from [10.47.88.201] (10.47.88.201) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 9 Jun 2022 18:54:02 +0100 Message-ID: <9b1d155e-28cc-08dc-5a5a-8580132575e7@huawei.com> Date: Thu, 9 Jun 2022 18:54:01 +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: [PATCH v3 3/4] scsi: core: Cap shost max_sectors according to DMA optimum mapping limits To: Bart Van Assche , , , , , , , , References: <1654507822-168026-1-git-send-email-john.garry@huawei.com> <1654507822-168026-4-git-send-email-john.garry@huawei.com> <31417477-953d-283e-808e-cf8701e820a8@huawei.com> <5b214e95-dd95-551a-496e-a2139a74e8eb@huawei.com> In-Reply-To: X-Originating-IP: [10.47.88.201] X-ClientProxiedBy: lhreml727-chm.china.huawei.com (10.201.108.78) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Cc: linux-scsi@vger.kernel.org, linux-doc@vger.kernel.org, liyihang6@hisilicon.com, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, iommu@lists.linux-foundation.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: John Garry via iommu Reply-To: John Garry Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On 09/06/2022 18:18, Bart Van Assche wrote: >>> >>> SCSI host bus adapters that support 64-bit DMA may support much >>> larger transfer sizes than 128 KiB. >> >> Indeed, and that is my problem today, as my storage controller is >> generating DMA mapping lengths which exceeds 128K and they slow >> everything down. >> >> If you say that SRP enjoys best peformance with larger transfers then >> can you please test this with an IOMMU enabled (iommu group type DMA >> or DMA-FQ)? > > Hmm ... what exactly do you want me to test? Do you perhaps want me to > measure how much performance drops with an IOMMU enabled? Yes, I would like to know of any performance change with an IOMMU enabled and then with an IOMMU enabled and including my series. > I don't have > access anymore to the SRP setup I referred to in my previous email. But > I do have access to devices that boot from UFS storage. For these > devices we need to transfer 2 MiB per request to achieve full bandwidth. ok, but do you have a system where the UFS host controller is behind an IOMMU? I had the impression that UFS controllers would be mostly found in embedded systems and IOMMUs are not as common on there. Thanks, John _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu