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=-10.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 41739C433FE for ; Wed, 9 Dec 2020 14:45:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 15266233EA for ; Wed, 9 Dec 2020 14:45:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733070AbgLIOpR (ORCPT ); Wed, 9 Dec 2020 09:45:17 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:23670 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733060AbgLIOpJ (ORCPT ); Wed, 9 Dec 2020 09:45:09 -0500 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0B9EXfMg167391; Wed, 9 Dec 2020 09:42:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=pp1; bh=9yaToXePl5w30PZNMLzXKenGOVLUECi6fnk4Bwg1kqs=; b=egH335cyF4EjWtM14prZHcXm1ncwClP38Bi8eTZcJJ/MxRY9ZhaF6ze5TsExStyD5UnQ 6C4yxz8rdZ+5iPWAGRC919JIZLKAq/qQlkb7+UOGyR9nLNG4sVSGOX7EwEXmw7IJkm0M wjLwDIWexNLZzBIRNsb1wci7MQYCsC0HtlJcIziITUqWKdxAg09uFWv3XOtzvHA6OF6m igc3qWZa8BdGD0F6lVt6eoazgejts8wg+Z+WtHPfjtddCjuoW9BKRejPybcX9ijErFUH BQzKwDJPRJphYrGTfFrtK6igoWKWKPx2NA0ZOmhcXuLMwxkAXILCa1z1ZIBcEGrCafmm AA== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 35avder39x-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 09 Dec 2020 09:42:51 -0500 Received: from m0098394.ppops.net (m0098394.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 0B9EYpfd178675; Wed, 9 Dec 2020 09:42:51 -0500 Received: from ppma02dal.us.ibm.com (a.bd.3ea9.ip4.static.sl-reverse.com [169.62.189.10]) by mx0a-001b2d01.pphosted.com with ESMTP id 35avder35a-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 09 Dec 2020 09:42:51 -0500 Received: from pps.filterd (ppma02dal.us.ibm.com [127.0.0.1]) by ppma02dal.us.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 0B9Ec9rQ009612; Wed, 9 Dec 2020 14:42:41 GMT Received: from b01cxnp23034.gho.pok.ibm.com (b01cxnp23034.gho.pok.ibm.com [9.57.198.29]) by ppma02dal.us.ibm.com with ESMTP id 3581ua06gf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 09 Dec 2020 14:42:41 +0000 Received: from b01ledav001.gho.pok.ibm.com (b01ledav001.gho.pok.ibm.com [9.57.199.106]) by b01cxnp23034.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 0B9Ege1S12059340 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 9 Dec 2020 14:42:40 GMT Received: from b01ledav001.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 94DB428059; Wed, 9 Dec 2020 14:42:40 +0000 (GMT) Received: from b01ledav001.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A28E228058; Wed, 9 Dec 2020 14:42:38 +0000 (GMT) Received: from [9.211.50.183] (unknown [9.211.50.183]) by b01ledav001.gho.pok.ibm.com (Postfix) with ESMTP; Wed, 9 Dec 2020 14:42:38 +0000 (GMT) Subject: Re: [PATCH v2] vfio iommu type1: Improve vfio_iommu_type1_pin_pages performance To: Cornelia Huck , "xuxiaoyang (C)" Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Alex Williamson , kwankhede@nvidia.com, wu.wubin@huawei.com, maoming.maoming@huawei.com, xieyingtai@huawei.com, lizhengui@huawei.com, wubinfeng@huawei.com, Zhenyu Wang , Zhi Wang References: <60d22fc6-88d6-c7c2-90bd-1e8eccb1fdcc@huawei.com> <4d58b74d-72bb-6473-9523-aeaa392a470e@huawei.com> <20201209125450.3f5834ab.cohuck@redhat.com> From: Eric Farman Message-ID: <9e37b8d9-3654-5b89-e3b4-5e6ede736320@linux.ibm.com> Date: Wed, 9 Dec 2020 09:42:37 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.3.1 MIME-Version: 1.0 In-Reply-To: <20201209125450.3f5834ab.cohuck@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.343,18.0.737 definitions=2020-12-09_13:2020-12-09,2020-12-09 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 mlxlogscore=999 malwarescore=0 bulkscore=0 lowpriorityscore=0 impostorscore=0 clxscore=1011 phishscore=0 adultscore=0 spamscore=0 priorityscore=1501 suspectscore=9 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012090104 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/9/20 6:54 AM, Cornelia Huck wrote: > On Tue, 8 Dec 2020 21:55:53 +0800 > "xuxiaoyang (C)" wrote: > >> On 2020/11/21 15:58, xuxiaoyang (C) wrote: >>> vfio_pin_pages() accepts an array of unrelated iova pfns and processes >>> each to return the physical pfn. When dealing with large arrays of >>> contiguous iovas, vfio_iommu_type1_pin_pages is very inefficient because >>> it is processed page by page.In this case, we can divide the iova pfn >>> array into multiple continuous ranges and optimize them. For example, >>> when the iova pfn array is {1,5,6,7,9}, it will be divided into three >>> groups {1}, {5,6,7}, {9} for processing. When processing {5,6,7}, the >>> number of calls to pin_user_pages_remote is reduced from 3 times to once. >>> For single page or large array of discontinuous iovas, we still use >>> vfio_pin_page_external to deal with it to reduce the performance loss >>> caused by refactoring. >>> >>> Signed-off-by: Xiaoyang Xu > > (...) > >> >> hi Cornelia Huck, Eric Farman, Zhenyu Wang, Zhi Wang >> >> vfio_pin_pages() accepts an array of unrelated iova pfns and processes >> each to return the physical pfn. When dealing with large arrays of >> contiguous iovas, vfio_iommu_type1_pin_pages is very inefficient because >> it is processed page by page. In this case, we can divide the iova pfn >> array into multiple continuous ranges and optimize them. I have a set >> of performance test data for reference. >> >> The patch was not applied >> 1 page 512 pages >> no huge pages： 1638ns 223651ns >> THP： 1668ns 222330ns >> HugeTLB： 1526ns 208151ns >> >> The patch was applied >> 1 page 512 pages >> no huge pages 1735ns 167286ns >> THP： 1934ns 126900ns >> HugeTLB： 1713ns 102188ns >> >> As Alex Williamson said, this patch lacks proof that it works in the >> real world. I think you will have some valuable opinions. > > Looking at this from the vfio-ccw angle, I'm not sure how much this > would buy us, as we deal with IDAWs, which are designed so that they > can be non-contiguous. I guess this depends a lot on what the guest > does. This would be my concern too, but I don't have data off the top of my head to say one way or another... > > Eric, any opinion? Do you maybe also happen to have a test setup that > mimics workloads actually seen in the real world? > ...I do have some test setups, which I will try to get some data from in a couple days. At the moment I've broken most of those setups trying to implement some other stuff, and can't revert back at the moment. Will get back to this. Eric