From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 53FCB438A1; Fri, 12 Jan 2024 11:57:01 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 1C3104028C; Fri, 12 Jan 2024 11:57:01 +0100 (CET) Received: from NAM04-MW2-obe.outbound.protection.outlook.com (mail-mw2nam04on2055.outbound.protection.outlook.com [40.107.101.55]) by mails.dpdk.org (Postfix) with ESMTP id EAF9C4026E for ; Fri, 12 Jan 2024 11:56:58 +0100 (CET) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Rox1iJJlhNHOiGNUyWB9xl0dvL6Qx7VQglPpqzUFf7DHHNi694qtS5qs90lt6KcstkT5FNxcN+xtiXTedlXTA5egQ9ddkU+EF3rm/E/8/fa+Ucc6aMRLnRb0KidtSrgV5CwIyN+JTwVxCIblstiWfIf8RUF6DxvDQR+0n8twRH3DTEbQTdDsmUpo4byL+lS5Kci/8C6BL3Jq4hwO6wA1LLgv4c+n5uGL4AHt7ms0d80zeXqd/q8MNmdK67W3oF/MSHazB+16SYcnwoNUt/GPtHQ2PvAgVQxWiuMT4JShM97Lt2kss2g/cCOwKQ5ic+rZtpFdn1fKJHsCrSJtCZHzfQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=fxYVgKczi62D+OGs3kF7sCVCyuCnWeVYrfOg2m/AjGA=; b=OYrqLifXR1HzU5xWlzOu7r/4Va9PdWBuDQ669x7lHlbykfdL9ilUGzCYnOQXPvJGUnJ3Oxc1tqBk8S1mQ/RFKWwVtXZ841OmtRwZKtjunrpyzvCLpUX9elUtfDMFPWmRR3OAzadNP1Ya0nQR9Oh7Xy1rR/rQJH68FLZyHdDF15Zjm3b7b5fqe4VCVt4WNNhnA6cVxCFv3Z3j769PIUBsMHrzfzPfN508jV0tfhMe3tTq8HIsmvScGLBugyAem4O9DGUIinJthkbAsKGZFsolnuRpdUcn1Lgd9leq0mtjjtc575DIJM70+d/OSrlzbzf3wnlt+otu7hCIbRjeXDJ39g== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=amd.com; dmarc=pass action=none header.from=amd.com; dkim=pass header.d=amd.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=fxYVgKczi62D+OGs3kF7sCVCyuCnWeVYrfOg2m/AjGA=; b=nakKzp/1GeYsGzXaKaeclNvoUs7M77zghWsvaFX1Y3bmA12BSQq6GdBCEPVnXPqDJ6k0W+M+3zX/1A96lK7WLAlTNpkiQVXwAlzNlrtL3lLtXZrXyqD1uP/9puO6zVpUsq38MtWvm/npANroGyGRGddtad9SsqUMsgDHALFxmi8= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from CH2PR12MB4294.namprd12.prod.outlook.com (2603:10b6:610:a9::11) by DM6PR12MB4092.namprd12.prod.outlook.com (2603:10b6:5:214::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7181.18; Fri, 12 Jan 2024 10:56:56 +0000 Received: from CH2PR12MB4294.namprd12.prod.outlook.com ([fe80::815a:45e6:cf5e:479f]) by CH2PR12MB4294.namprd12.prod.outlook.com ([fe80::815a:45e6:cf5e:479f%4]) with mapi id 15.20.7181.018; Fri, 12 Jan 2024 10:56:55 +0000 Message-ID: <65c85f06-3cdc-44f2-9a17-217dfcbf7fad@amd.com> Date: Fri, 12 Jan 2024 10:56:39 +0000 User-Agent: Mozilla Thunderbird Subject: Re: [dpdk-dev] [RFC] ethdev: support Tx queue free descriptor query Content-Language: en-US To: =?UTF-8?Q?Morten_Br=C3=B8rup?= , Bruce Richardson , jerinj@marvell.com Cc: dev@dpdk.org, Thomas Monjalon , Andrew Rybchenko , ferruh.yigit@xilinx.com, ajit.khaparde@broadcom.com, aboyer@pensando.io, beilei.xing@intel.com, chas3@att.com, chenbo.xia@intel.com, ciara.loftus@intel.com, dsinghrawat@marvell.com, ed.czeck@atomicrules.com, evgenys@amazon.com, grive@u256.net, g.singh@nxp.com, zhouguoyang@huawei.com, haiyue.wang@intel.com, hkalra@marvell.com, heinrich.kuhn@corigine.com, hemant.agrawal@nxp.com, hyonkim@cisco.com, igorch@amazon.com, irusskikh@marvell.com, jgrajcia@cisco.com, jasvinder.singh@intel.com, jianwang@trustnetic.com, jiawenwu@trustnetic.com, jingjing.wu@intel.com, johndale@cisco.com, john.miller@atomicrules.com, linville@tuxdriver.com, keith.wiles@intel.com, kirankumark@marvell.com, oulijun@huawei.com, lironh@marvell.com, longli@microsoft.com, mw@semihalf.com, spinler@cesnet.cz, matan@nvidia.com, matt.peters@windriver.com, maxime.coquelin@redhat.com, mk@semihalf.com, humin29@huawei.com, pnalla@marvell.com, ndabilpuram@marvell.com, qiming.yang@intel.com, qi.z.zhang@intel.com, radhac@marvell.com, rahul.lakkireddy@chelsio.com, rmody@marvell.com, rosen.xu@intel.com, sachin.saxena@oss.nxp.com, skoteshwar@marvell.com, shshaikh@marvell.com, shaibran@amazon.com, shepard.siegel@atomicrules.com, asomalap@amd.com, somnath.kotur@broadcom.com, sthemmin@microsoft.com, steven.webster@windriver.com, skori@marvell.com, mtetsuyah@gmail.com, vburru@marvell.com, viacheslavo@nvidia.com, xiao.w.wang@intel.com, cloud.wangxiaoyun@huawei.com, yisen.zhuang@huawei.com, yongwang@vmware.com, xuanziyang2@huawei.com, cristian.dumitrescu@intel.com References: <20231219172948.3909749-1-jerinj@marvell.com> <98CBD80474FA8B44BF855DF32C47DC35E9F11E@smartserver.smartshare.dk> From: Ferruh Yigit Autocrypt: addr=ferruh.yigit@amd.com; keydata= xsFNBGJDD3EBEAC/M7Tk/DfQSmP1K96vyzdhfSBzlCaGtcxNXorq4fALruqVsD3oi0yfyEz9 4YN8x7py0o9EL8ZdpOX0skc0AMCDAaw033uWhCn0GLMeGRKUbfOAPvL6ecSDvGD7CJIO9j0J eZUvasBgPdM/435PEr9DmC6Ggzdzt8IuG4PoLi5jpFSfcqxZFCCxLUDEo/w0nuguk2FTuYJg B2zEZ4JTBZrw7hIHiFh8D8hr6YA6a5uTofq1tr+l048lbtdFUl8TR0aIExVzE4Z8qKZlcE+9 RQaewjK5Al1jLE4sHdmd3GN+IvgDF3D/fLsi25SKJDeGSdeHkOmaX0qGeM4WKIfU6iARRCiQ N3AmBIxZ/A7UXBKLaOyZ+/i3sE6Wb53nrO4i8+0K2Qwyh6LjTeiJAIjYKN43ppxz3DaI+QwQ vI+uyHr4Gg0Da9EPPz/YyKauSeOZCfCB5gIfICO0j6x0SCl8uQ2nLpjxcZkf0gjcwUzP3h+S 3x6NfDji9YEij0zczW/dcSpGgZ6vsFpPrtnP9ZXy6J53yp0kJtOJoOlkEFFdU2yCZnCDseum CoudmGLZVvS0/DzHDJejq+3kK3FDGktZBOxZIIpal+nFqS7lVgOZc4+huVv3jyhzoAUOEyXA XK5j6o7g8STUY+z33QNnHpdLvecMwuzmvqy0jR54yAbZ64mB9QARAQABzSNGZXJydWggWWln aXQgPGZlcnJ1aC55aWdpdEBhbWQuY29tPsLBlwQTAQgAQQIbAwULCQgHAgYVCgkICwIEFgID AQIeAQIXgAIZARYhBEm7aYjps5XGsPHCElRTPtCKKm/6BQJkdyEEBQkE3meNAAoJEFRTPtCK Km/6UdcP/0/kEp49aIUhkRnQfmKmNVpcBEs4NqceNCWTQlaXdEwL1lxf1L49dsF5Jz1yvWi3 tMtq0Mk1o68mQ7q8iZAzIeLxGQAlievMNE0BzLWPFmuX+ac98ITBqKdnUAn6ig5ezR+jxrAU 58utUszDl16eMabtCu76sINL5izB8zCWcDEUB4UqM8iBSQZ7/a7TSBVS0jVBldAORg1qfFIs cGMPQn/skhy3QqbK3u3Rhc44zRxvzrQJmhY6T1rpeniHSyGOeIYqjpbpnMU5n1VWzQ4NXvAD VDkZ4NDw6CpvF4S2h2Ds7w7GKvT6RRTddrl672IaLcaWRiqBNCPm+eKh4q5/XkOXTgUqYBVg Ors8uS9EbQC/SAcp9VHF9fB+3nadxZm4CLPe5ZDJnSmgu/ea7xjWQYR8ouo2THxqNZtkercc GOxGFxIaLcJIR/XChh9d0LKgc1FfVARTMW8UrPgINVEmVSFmAVSgVfsWIV+NSpG9/e90E4SV gMLPABn1YpJ8ca/IwqovctqDDXfxZOvCPOVWTzQe/ut767W+ctGR1kRkxWcz470SycOcY+PW VRPJd91Af0GdLFkwzZgNzkd6Gyc9XXcv4lwwqBLhWrBhqPYB0aZXIG1E/cVTiRp4dWpFHAFD DcuLldjIw93lCDsIeEDM9rBizGVMWEoeFmqSe7pzGTPXzsFNBGJDD3EBEAC8fBFQHej8qgIG CBzoIEd1cZgPIARlIhRudODXoNDbwA+zJMKtOVwol3Hh1qJ2/yZP11nZsqrP4fyUvMxrwhDe WBWFVDbWHLnqXMnKuUU1vQMujbzgq/4Rb9wSMW5vBL6YxhZng+h71JgS/9nVtzyaTtsOTrJi 6nzFSDx6Wbza2jYvL9rlK0yxJcMEiKwZQ/if4KcOesD0rtxomU/iSEv6DATcJbGXP6T93nPl 90XksijRKAmOwvdu3A8IIlxiSSVRP0lxiHOeR35y6PjHY2usfEDZZOVOfDfhlCVAIBZUZALv VmFOVSTYXeKgYa6Ooaf72+cHM3SgJIbYnevJfFv8YQW0MEAJ/IXE7B1Lk+pHNxwU3VBCrKnA fd/PTvviesuYRkrRD6qqZnINeu3b2DouVGGt2fVcGA38BujCd3p8i7azoGc7A6cgF7z9ETnr ANrbg1/dJyDmkDxOxVrVquTBbxJbDy2HaIe9wyJTEK2Sznpy62DaHVY+gfDQzexBXM10geHC IIUhEnOUYVaq65X3ZDjyAQnNDBQ4uMqSHZk8DpJ22X+T+IMzWzWl+VyU4UZXjkLKPvlqPjJk 1RbKScek5L2GhxHQbPaD76Hx4Jiel0vm2G+4wei8Ay1+0YRFkhySxogU/uQVXHTv63KzQMak oIfnN/V2R0ucarsvMBW+gwARAQABwsF8BBgBCAAmAhsMFiEESbtpiOmzlcaw8cISVFM+0Ioq b/oFAmR3IPsFCQTeZ44ACgkQVFM+0Ioqb/qINhAAtcor9bevHy22HvJvXX17IOpPSklZJAeQ Az43ZEo5kRlJ8mElc2g3RzYCvL/V3fSiIATxIsLq/MDtYhO8AAvklxND/u2zeBd7BkRZTZZX W1V1cM3oTvfx3LOhDu4f2ExQzCGdkzbXTRswSJIe1W0qwsDp+YPekbrsKp1maZArGeu+6FuW honeosIrWS98QJmscEhP8ooyJkLDCCOgEk+mJ/JBjzcJGuYn6+Iy/ApMw/vqiLGL1UWekcTA g18mREHqIR+A3ZvypIufSFB52oIs1zD/uh/MgmL62bY/Cw6M2SxiVxLRsav9TNkF6ZaNQCgn GqifliCEMvEuLZRBOZSYH2A/PfwjYW0Ss0Gyfywmb2IA990gcQsXxuCLG7pAbWaeYazoYYEQ NYmWatZNMAs68ERI2zvrVxdJ/fBWAllIEd0uQ4P05GtAHPdTIDQYp545+TPV7oyF0LfXcsQs SFVZE6igdvkjfYmh+QOrHGZvpWXLTmffVf/AQ81wspzbfxJ7sYM4P8Mg5kKOsaoUdyA/2qVe cMh1CLUHXF1GlofpGbe1lj4KUJVse5g3qwV7i9VrseA8c4VIZewdIjkzAhmmbxl+8rM/LKBH dZUMTzME5PFCXJIZ83qkZQ795MTe2YScp9dIV7fsS5tpDwIs7BZNVM1l3NAdK+DLHqNxKuyO 8Zk= In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC35E9F11E@smartserver.smartshare.dk> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-ClientProxiedBy: FR4P281CA0184.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:ca::19) To CH2PR12MB4294.namprd12.prod.outlook.com (2603:10b6:610:a9::11) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH2PR12MB4294:EE_|DM6PR12MB4092:EE_ X-MS-Office365-Filtering-Correlation-Id: fa7da57e-98d5-4a79-f811-08dc135d30e6 X-LD-Processed: 3dd8961f-e488-4e60-8e11-a82d994e183d,ExtAddr X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:CH2PR12MB4294.namprd12.prod.outlook.com; PTR:; CAT:NONE; SFS:(13230031)(366004)(39860400002)(376002)(396003)(346002)(136003)(230922051799003)(64100799003)(1800799012)(186009)(451199024)(31686004)(2906002)(7406005)(5660300002)(7366002)(478600001)(7416002)(44832011)(4326008)(41300700001)(54906003)(8936002)(110136005)(8676002)(66946007)(66556008)(36756003)(316002)(6486002)(31696002)(6666004)(86362001)(53546011)(6506007)(66476007)(66574015)(2616005)(38100700002)(83380400001)(26005)(6512007)(43740500002)(45980500001); DIR:OUT; SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?MTZVTTJpR2lHUXBZMitaY2srejZhdmZTZUUwajZGcVlkZUc1MUFCNUlyZ1Z6?= =?utf-8?B?Ly9rd242d0phRzMzWWh5QU9ZL0VzdzFCZlpMa2p2ekdaRjBwSEMxeFlEZEZZ?= =?utf-8?B?dzY3N201TUZhRm5KMmd6ZjQ3YXg5NmFqUFE0QU44N0Y1eEZZNWJPODBGaXhi?= =?utf-8?B?bUhDM0lseFdDdVlDaEFyR0RDczhhRTlSQksvSzU2T0E1NkU1SDNaZUk5N1Z5?= =?utf-8?B?bkRSSTFtY3IreXlCV01ZSmlkVXdGUFpYVmQ5MlJ0WFdxQmJZdFQyUXcwa2or?= =?utf-8?B?VFoxMUpvVmFqUEVoNXBySlNBcnkrNWQ3Qml5d3NHYk5zeE1TZUR2WU52eTQ1?= =?utf-8?B?d3hPQ2ZWZi9Kb0RObkk5SVYxOUdaOWdIZHVML2wrVVlEdEVHZ09zMVJHSjEy?= =?utf-8?B?dmdLV0R5dnptZWp3TnN0aUJrQzV6bitkQW9LQXY5eDgycmpKSW5Oa09ldC81?= =?utf-8?B?UXZ1MkhJSkxxeU5obDJlUzRvZzNOUm9kRExRTkZpM01Ga1FJVlB0WCt1Mmll?= =?utf-8?B?MG9za2t2MHZFS1JidzVnZFBlRFcvSG5nZ2h1bDJxelJycEZSK2VyY1BqYUJH?= =?utf-8?B?LzY4NGFKaFBoRWUvSmZvd1NVbjY5V0JKWVgzZ25aTFFOSS82eTJPeXdydTVE?= =?utf-8?B?emdlb3djaFRHNHl0M2JpMEM5VnM4U2ZQUXZ3ejdvQ1F6OUppenRNVWhaRkNo?= =?utf-8?B?cXdaVkJLMldlR0g2c3V1OW1FSXFnOVdMOEhXTkh5SVFEWmY0UnZKZ2tMS003?= =?utf-8?B?YnNkUUw1ZThxaURhVHczRXlwMC9pNnc1ZlY3dEs2a285Q3ZodXdDQWMxSmlG?= =?utf-8?B?OTRFY3Q0d2RUQjJ4S1lVYkVqaXdYb1FMM0Q1cTF0emh1NUhrUm4zNkVYVkJM?= =?utf-8?B?ajF2NXV6Z2o0T0lFUlIzT0JoSHc5eGR3NmdrenpQczVkN3ZsaG1CN3pBQmdK?= =?utf-8?B?c1pNenNxMmltZVpIeGJkMERxZThGckRqQWkxNXVCZzQrNkJtdmNQSGhoaDJN?= =?utf-8?B?dEloS3RreENxVkdEMzRJSzM3U0xyWGNQNWdkbTRhQ3hERUFZMFFXOExkSy9D?= =?utf-8?B?WGtCSkovcHVEb3lKbDNReXlmbmdMQWZueWFCRy9CK282RDNGdTBNTVR3cXJn?= =?utf-8?B?TkZzcWRRSDVwK2lHMnU2NnJicWhrTHczRy9SU3FRYUVZQUV4aXMwbDZWRHVO?= =?utf-8?B?bDVTWFZFUi91YzJJMkxRT1ViNk4xZzdaQW03Y0dqR1llZ2pIc3BRUjdzalNL?= =?utf-8?B?TVl6bDAxMzJUWDF4VVhlM040R1NSVC95dUoraEVTOE9ZQ1R0Q1MvbVArNTYx?= =?utf-8?B?M25LakoyV1FBL3JsVVNlcmhMbnIvdVdGU1hUandoMWRIcXRRRlIxWHFFemRT?= =?utf-8?B?azhDNmk0OGlZMXNoK25hbjYrMHdMSWJVZmhsOWMxMVQ0TTdYQktlVlRkeUR6?= =?utf-8?B?c3FLRGF3ZGh5NW9iNE51UFZJdlB3TFkzTmdGQnBrWlE5a0toM29Odk0rVTU4?= =?utf-8?B?MzFZdUdHRjgxVlA0WHorTEY1bGVIZVl4T1R4QnFVWTdXNXRBQkU5SnhtMDZh?= =?utf-8?B?OHRRZ04zVmVoNUVOWCt6ZlhiUnhIOTlJY3JDRUhPNHNsdzh5cFgvTDdTeDNZ?= =?utf-8?B?d3VYY1I0RU5rWmx0UGZXVDFZcVZIeEFxM3R0ZUxGdWtmdFdCMThPVFlnME8r?= =?utf-8?B?YjdaSitnR0ZEck52SDlhaXZGcE1VYnYyMDJCQmRIM3pUcWtkazlIOEhKTGtZ?= =?utf-8?B?OEhEMS9ZL1c2ZTc0U3BnTG10d09qNzE3NTd3aklTOUs4SFJWeGhTKzk5elI1?= =?utf-8?B?cFovdnBHSVAvZEtBR2tBOU0ydHVEQ0JOd3duLzRRYVNUcUN2MjNoWFZJamJB?= =?utf-8?B?QW5nSm1aUk5CVVloak1jY1I5cXFqazJITy84QmxaT0I0ckhlZVBjZXhUUUI4?= =?utf-8?B?bDdpUFljK3NlMTI0a0VIT3B6ZXZDOTU3dGNuaExHN3B6eHJLRWNOanQ4ZEJa?= =?utf-8?B?MmZuTGxCK21ybEJmUFRINlNEbWI0YUFDczNJa1JOS0xlcHdubGNGR3kxdFc5?= =?utf-8?B?UEcwMm1ibUp3bjhFakdYblBFSTNrcU5Ld004d25zWlNXSTVHU2tDWW4vME1B?= =?utf-8?Q?nZdg=3D?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: fa7da57e-98d5-4a79-f811-08dc135d30e6 X-MS-Exchange-CrossTenant-AuthSource: CH2PR12MB4294.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 Jan 2024 10:56:55.6394 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 4fCWNA25w1DxybjFutkNOVPWjzsp2tA8hHTQ8ngauHtBJyx6plsEO853veveA8e3 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR12MB4092 X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On 1/8/2024 9:15 PM, Morten Brørup wrote: >> From: Bruce Richardson [mailto:bruce.richardson@intel.com] >> Sent: Monday, 8 January 2024 11.54 >> >> On Tue, Dec 19, 2023 at 10:59:48PM +0530, jerinj@marvell.com wrote: >>> From: Jerin Jacob >>> >>> Introduce a new API to retrieve the number of available free >> descriptors >>> in a Tx queue. Applications can leverage this API in the fast path to >>> inspect the Tx queue occupancy and take appropriate actions based on >> the >>> available free descriptors. >>> >>> A notable use case could be implementing Random Early Discard (RED) >>> in software based on Tx queue occupancy. >>> >>> Signed-off-by: Jerin Jacob >>> --- >> >> Hi Jerin, >> >> while I don't strongly object to this patch, I wonder if it encourages >> sub-optimal code implementations. To determine the number of free >> descriptors in a ring, the driver in many cases will need to do a scan >> of >> the descriptor ring to see how many are free/used. However, I suspect >> that >> in most cases we will see something like the following being done: >> >> count = rte_eth_rx_free_count(); > > Typo: rte_eth_rx_free_count() -> rte_eth_tx_free_count() > >> if (count > X) { >> /* Do something */ >> } >> >> For instances like this, scanning the entire ring is wasteful of >> resources. >> Instead it would be better to just check the descriptor at position X >> explicitly. Going to the trouble of checking the exact descriptor count >> is >> unnecessary in this case. > > Yes, it introduces such a risk. > All DPDK examples simply call tx_burst() without checking free space first, so I think the probability (of the simple case) is low. > And the probability for the case comparing to X could be mitigated by referring to rte_eth_tx_descriptor_status() in the function description. > Agree on the risk, perhaps adding some documentation to the API helps, we can highlight intended usecase is QoS implementations, like RED etc.. >> >> Out of interest, are you aware of a case where an app would need to >> know >> exactly the number of free descriptors, and where the result would not >> be >> just compared to one or more threshold values? Do we see cases where it >> would be used in a computation, perhaps? > > Yes: RED. When exceeding the minimum threshold, the probability of marking/dropping a packet increases linearly with the queue's fill level. > E.g.: > 0-900 packets in queue: don't drop, > 901-1000 packets in queue: probability of dropping the packet is 1-100 % (e.g. 980 packets in queue = 80 % drop probability). > >