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 X-Spam-Level: X-Spam-Status: No, score=-5.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3245C432BE for ; Mon, 26 Jul 2021 07:51:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D791360560 for ; Mon, 26 Jul 2021 07:51:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232308AbhGZHLY (ORCPT ); Mon, 26 Jul 2021 03:11:24 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]:3481 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231332AbhGZHLX (ORCPT ); Mon, 26 Jul 2021 03:11:23 -0400 Received: from fraeml704-chm.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4GYBZW2VHFz6BBDR; Mon, 26 Jul 2021 15:36:51 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) 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 15.1.2176.2; Mon, 26 Jul 2021 09:51:50 +0200 Received: from [10.47.94.42] (10.47.94.42) 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 15.1.2176.2; Mon, 26 Jul 2021 08:51:50 +0100 Subject: Re: [bug report] iommu_dma_unmap_sg() is very slow then running IO from remote numa node To: Ming Lei , Robin Murphy CC: , , , Will Deacon , References: <74537f9c-af5f-cd84-60ab-49ca6220310e@huawei.com> <9c929985-4fcb-e65d-0265-34c820b770ea@huawei.com> <0adbe03b-ce26-e4d3-3425-d967bc436ef5@arm.com> From: John Garry Message-ID: <6ceab844-465f-3bf3-1809-5df1f1dbbc5c@huawei.com> Date: Mon, 26 Jul 2021 08:51:32 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.94.42] X-ClientProxiedBy: lhreml748-chm.china.huawei.com (10.201.108.198) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23/07/2021 11:21, Ming Lei wrote: >> Thanks, I was also going to suggest the latter, since it's what >> arm_smmu_cmdq_issue_cmdlist() does with IRQs masked that should be most >> indicative of where the slowness most likely stems from. > The improvement from 'iommu.strict=0' is very small: > Have you tried turning off the IOMMU to ensure that this is really just an IOMMU problem? You can try setting CONFIG_ARM_SMMU_V3=n in the defconfig or passing cmdline param iommu.passthrough=1 to bypass the the SMMU (equivalent to disabling for kernel drivers). Thanks, John