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Tue, 17 Mar 2020 15:01:00 +0000 Date: Tue, 17 Mar 2020 17:00:57 +0200 From: Leon Romanovsky To: Andrew Boyer Cc: linux-rdma@vger.kernel.org Subject: Re: Lockless behavior for CQs in userspace Message-ID: <20200317150057.GJ3351@unreal> References: <6C1A3349-65B0-4F22-8E82-1BBC22BF8CA2@pensando.io> Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <6C1A3349-65B0-4F22-8E82-1BBC22BF8CA2@pensando.io> X-ClientProxiedBy: AM3PR07CA0093.eurprd07.prod.outlook.com (2603:10a6:207:6::27) To AM6PR05MB6408.eurprd05.prod.outlook.com (2603:10a6:20b:b8::23) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from localhost (2a00:a040:183:2d::393) by AM3PR07CA0093.eurprd07.prod.outlook.com (2603:10a6:207:6::27) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2835.11 via Frontend Transport; Tue, 17 Mar 2020 15:00:59 +0000 X-Originating-IP: [2a00:a040:183:2d::393] X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-HT: Tenant X-MS-Office365-Filtering-Correlation-Id: cc795018-e570-46e2-1938-08d7ca840101 X-MS-TrafficTypeDiagnostic: AM6PR05MB5991: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:8882; X-Forefront-PRVS: 0345CFD558 X-Forefront-Antispam-Report: SFV:NSPM;SFS:(10009020)(4636009)(7916004)(396003)(366004)(346002)(376002)(39860400002)(136003)(199004)(81166006)(16526019)(81156014)(186003)(8936002)(8676002)(966005)(6916009)(5660300002)(2906002)(4326008)(478600001)(33656002)(66946007)(86362001)(66476007)(66556008)(316002)(4744005)(52116002)(9686003)(6496006)(33716001)(1076003)(6486002);DIR:OUT;SFP:1101;SCL:1;SRVR:AM6PR05MB5991;H:AM6PR05MB6408.eurprd05.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1; Received-SPF: None (protection.outlook.com: mellanox.com does not designate permitted sender hosts) X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-MS-Exchange-AntiSpam-MessageData: RWwV8EbazPKOihORxdIsYIjBZz4igjakbLMrnTXPUjOnaowbl20Np8OpxRsYDp9sNWUZnvBQp3bVyeLgm1INnbdQd8vzlP4YOwFRbnUlHdOpkyimsx+hm8dOBCysPWHYLVM8L0Z9pr047KHwX1Erk4yHv/ve6N3SaR4XfOt1wzg= X-OriginatorOrg: Mellanox.com X-MS-Exchange-CrossTenant-Network-Message-Id: cc795018-e570-46e2-1938-08d7ca840101 X-MS-Exchange-CrossTenant-OriginalArrivalTime: 17 Mar 2020 15:00:59.9186 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: a652971c-7d2e-4d9b-a6a4-d149256f461b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 0TSVoGxSMfcdVH9cl0euME1bB1XGyuISWPbAsdOVHO4r0Ryd7XnIVX3EHh6SG8JiRS0RP38GK0AstRVUfy4eWw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM6PR05MB5991 Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Tue, Mar 17, 2020 at 10:45:08AM -0400, Andrew Boyer wrote: > Hello Leon, > I understand that we are not to create new providers that use environment variables to control locking behavior. The ‘new’ way to do it is to use thread domains and parent domains. > > However, even mlx5 still uses the env var exclusively to control lockless behavior for CQs. Do you have anything in mind for how to extend thread_domains or some other part of the API to cover the CQ case? Which parameter did you have in mind? I would say that all those parameters are coming from pre-rdma-core era. Doesn't this commit do what you are asking? https://github.com/linux-rdma/rdma-core/commit/0dbde57c59d2983e848c3dbd9ae93eaf8e7b9405 Thanks > > Thank you, > Andrew >