From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <matan@mellanox.com> Received: from EUR01-DB5-obe.outbound.protection.outlook.com (mail-db5eur01on0062.outbound.protection.outlook.com [104.47.2.62]) by dpdk.org (Postfix) with ESMTP id BB0BF1B01C for <dev@dpdk.org>; Thu, 25 Jan 2018 10:36:41 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Mellanox.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version; bh=E2PV2wz16/G9HMh4FZbfJXePYJG9lU/t21WUSmivznM=; b=BWfvPjnaWTUbphwd4rijjcRJNnH6oEObGlGyqXMJ6O8NX+UFXimoJT1z5UCFpwsVb9EFffXBplXeqAtWVmig6cs0PYA5qlvTb4bRFdvJ6vz9Cjca2IqXaMflrYuPjggLcRO2gcYx1v8obTDht+cDxGO2WVcIsAL/hz0/XuNw4sQ= Received: from AM6PR0502MB3797.eurprd05.prod.outlook.com (52.133.21.26) by AM6PR0502MB4085.eurprd05.prod.outlook.com (52.133.30.160) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P256) id 15.20.444.14; Thu, 25 Jan 2018 09:36:39 +0000 Received: from AM6PR0502MB3797.eurprd05.prod.outlook.com ([fe80::6c28:c6b3:de94:a733]) by AM6PR0502MB3797.eurprd05.prod.outlook.com ([fe80::6c28:c6b3:de94:a733%13]) with mapi id 15.20.0444.015; Thu, 25 Jan 2018 09:36:39 +0000 From: Matan Azrad <matan@mellanox.com> To: Matan Azrad <matan@mellanox.com>, =?iso-8859-1?Q?Ga=EBtan_Rivet?= <gaetan.rivet@6wind.com>, "Ananyev, Konstantin" <konstantin.ananyev@intel.com>, Thomas Monjalon <thomas@monjalon.net> CC: "Wu, Jingjing" <jingjing.wu@intel.com>, "dev@dpdk.org" <dev@dpdk.org>, Neil Horman <nhorman@tuxdriver.com>, "Richardson, Bruce" <bruce.richardson@intel.com> Thread-Topic: [dpdk-dev] [PATCH v3 7/7] app/testpmd: adjust ethdev port ownership Thread-Index: AQHTlcAAsrC3L8dqnUaEGw/B6oZpaA== Date: Thu, 25 Jan 2018 09:36:39 +0000 Message-ID: <AM6PR0502MB37974A3305A09994C1CAB06DD2E10@AM6PR0502MB3797.eurprd05.prod.outlook.com> References: <1516293317-30748-8-git-send-email-matan@mellanox.com> <2601191342CEEE43887BDE71AB97725886280A68@irsmsx105.ger.corp.intel.com> <AM6PR0502MB37970EE52B78BA0B3E691A69D2EF0@AM6PR0502MB3797.eurprd05.prod.outlook.com> <2601191342CEEE43887BDE71AB97725886280AE8@irsmsx105.ger.corp.intel.com> <AM6PR0502MB3797B1AE571D56DBEB8C05CAD2EF0@AM6PR0502MB3797.eurprd05.prod.outlook.com> <20180119150017.mljpcdmldqx32mkq@bidouze.vm.6wind.com> <2601191342CEEE43887BDE71AB97725886281B1D@irsmsx105.ger.corp.intel.com> <AM6PR0502MB3797FB780B588499A71189DCD2EC0@AM6PR0502MB3797.eurprd05.prod.outlook.com> <2601191342CEEE43887BDE71AB97725886281E73@irsmsx105.ger.corp.intel.com> <AM6PR0502MB37976C3DFD1ABAF6439356BED2E30@AM6PR0502MB3797.eurprd05.prod.outlook.com> <20180123125637.p2kufd6n2erpiar5@bidouze.vm.6wind.com> <AM6PR0502MB37979FF971BEAE971C4714D6D2E30@AM6PR0502MB3797.eurprd05.prod.outlook.com> In-Reply-To: <AM6PR0502MB37979FF971BEAE971C4714D6D2E30@AM6PR0502MB3797.eurprd05.prod.outlook.com> Accept-Language: en-US, he-IL Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: spf=none (sender IP is ) smtp.mailfrom=matan@mellanox.com; x-originating-ip: [193.47.165.251] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1; AM6PR0502MB4085; 7:eqd/5l3zppCR6FetNQsT/0zKcXkv1OL43isgc4AnDsdGNEdl7o9qA/2OiA/P6DFA5u0B/ePoa9rGI43oZWRxIWVjeX40NN8kuFGXyWAgfHPUTmmyt6KBknPORsgkvnjV4TyuZ35noagFnMf6R6O0DtPV2JZfmih59GDkZrpG/Nn5k3twCMOsvQkrHjEaLi/QAmW9mxh39jsMbIPEWEe1N2ed4M6V85BNO4TTPHcNygDwnij+cOdShXdIYfboyaJc x-ms-exchange-antispam-srfa-diagnostics: SSOS; x-ms-office365-filtering-ht: Tenant x-ms-office365-filtering-correlation-id: ed70341a-25bf-4e90-b92c-08d563d722c3 x-microsoft-antispam: UriScan:; BCL:0; PCL:0; RULEID:(7020095)(4652020)(48565401081)(5600026)(4604075)(3008032)(2017052603307)(7153060)(7193020); SRVR:AM6PR0502MB4085; x-ms-traffictypediagnostic: AM6PR0502MB4085: x-ld-processed: a652971c-7d2e-4d9b-a6a4-d149256f461b,ExtAddr x-microsoft-antispam-prvs: <AM6PR0502MB4085E5C94BACDE566C313B08D2E10@AM6PR0502MB4085.eurprd05.prod.outlook.com> x-exchange-antispam-report-test: UriScan:(60795455431006)(278428928389397)(17755550239193); x-exchange-antispam-report-cfa-test: BCL:0; PCL:0; RULEID:(6040501)(2401047)(8121501046)(5005006)(93006095)(93001095)(3231023)(2400081)(944501161)(3002001)(10201501046)(6055026)(6041288)(20161123560045)(20161123564045)(201703131423095)(201702281528075)(20161123555045)(201703061421075)(201703061406153)(20161123562045)(20161123558120)(6072148)(201708071742011); SRVR:AM6PR0502MB4085; BCL:0; PCL:0; RULEID:; SRVR:AM6PR0502MB4085; x-forefront-prvs: 0563F2E8B7 x-forefront-antispam-report: SFV:NSPM; SFS:(10009020)(366004)(39380400002)(39860400002)(396003)(346002)(376002)(189003)(199004)(76104003)(55674003)(8936002)(99286004)(97736004)(33656002)(81156014)(81166006)(66066001)(54906003)(478600001)(3846002)(305945005)(7736002)(74316002)(68736007)(106356001)(229853002)(93886005)(316002)(110136005)(2906002)(2950100002)(55016002)(5250100002)(2900100001)(7696005)(6436002)(3660700001)(6506007)(76176011)(59450400001)(3280700002)(26005)(102836004)(105586002)(53936002)(4326008)(5660300001)(9686003)(6116002)(25786009)(86362001)(14454004)(6246003); DIR:OUT; SFP:1101; SCL:1; SRVR:AM6PR0502MB4085; H:AM6PR0502MB3797.eurprd05.prod.outlook.com; FPR:; SPF:None; PTR:InfoNoRecords; MX:1; A:1; LANG:en; received-spf: None (protection.outlook.com: mellanox.com does not designate permitted sender hosts) x-microsoft-antispam-message-info: uAkA9QJ4OpLcXZv8erlvUH6XFlNwQ3N7TsfxEG0YWlMIkt0OM2YfmEB89OX30GPxrBUnSsyBBoUf8kk2R7OsmQ== spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: Mellanox.com X-MS-Exchange-CrossTenant-Network-Message-Id: ed70341a-25bf-4e90-b92c-08d563d722c3 X-MS-Exchange-CrossTenant-originalarrivaltime: 25 Jan 2018 09:36:39.3757 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: a652971c-7d2e-4d9b-a6a4-d149256f461b X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM6PR0502MB4085 Subject: Re: [dpdk-dev] [PATCH v3 7/7] app/testpmd: adjust ethdev port ownership X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions <dev.dpdk.org> List-Unsubscribe: <https://dpdk.org/ml/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://dpdk.org/ml/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <https://dpdk.org/ml/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> X-List-Received-Date: Thu, 25 Jan 2018 09:36:41 -0000 Gaetan, Konstantin, Thomas Any response to my suggestion below? From: Matan Azrad > Hi >=20 > From: Ga=EBtan Rivet [mailto:gaetan.rivet@6wind.com] <snip> > > > > > > > Look, > > > > > > > > Testpmd initiates some of its internal databases depends > > > > > > > > on specific port iteration, In some time someone may take > > > > > > > > ownership of Testpmd ports and testpmd will continue to > > > > > > > > touch > > them. > > > > > > > > > > > > But if someone will take the ownership (assign new owner_id) > > > > > > that port will not appear in RTE_ETH_FOREACH_DEV() any more. > > > > > > > > > > > > > > > > Yes, but testpmd sometimes depends on previous iteration using > > internal database. > > > > > So it uses internal database that was updated by old iteration. > > > > > > > > That sounds like just a bug in testpmd that need to be fixed, no? > > > > > > If Testpmd already took ownership for these ports(like I did), it is = ok. > > > > > > > Have you tested using the default iterator (NO_OWNER)? > > It worked until now with the bare minimal device tagging using > > DEV_DEFERRED. Testpmd did not seem to mind having to skip this port. > > > > I'm sure there were places where this was overlooked, but overall, I'd > > think everything should be fixable using only the NO_OWNER iteration. >=20 > I don't think so. >=20 > > Can you point to a specific scenario (command line, chain of event) > > that would lead to a problem? > > >=20 > I didn't construct a race test to catch testpmd issue, but I think withou= t this > patch, there is a lot of issues. > Go to the testpmd code (before ownership) and find usage of the old > iterator(after the first iteration in main), Ask yourself what should hap= pen if > exactly in this time, a new port is created by fail-safe(plug in event). >=20 > > > > Any particular places where outdated device info is used? > > > > > > For example, look for the stream management in testpmd(I think I saw > > > it > > there). > > > > > > > The stream management is certainly shaky, but it happens after the EAL > > initial port creation, and is not able to update itself for new > > hotplugged ports (unless something changed). > > >=20 > Yes, but conceptually someone in the future may take the port(because it > ownerless). >=20 > > > > > > > If I look back on the fail-safe, its sole purpose is to have > > > > > > > seamless hotplug with existing applications. > > > > > > > > > > > > > > Port ownership is a genericization of some functions > > > > > > > introduced by the fail-safe, that could structure DPDK > > > > > > > further. It should allow applications to have a seamless > > > > > > > integration with subsystems using port ownership. Without > > > > > > > this, > > port ownership cannot be used. > > > > > > > > > > > > > > Testpmd should be fixed, but follow the most common design > > > > > > > patterns of DPDK applications. Going with port ownership > > > > > > > seems like a paradigm shift. > > > > > > > > > > > > > > > In addition > > > > > > > > Using the old iterator in some places in testpmd will > > > > > > > > cause a race for run- > > > > > > time new ports(can be created by failsafe or any hotplug code): > > > > > > > > - testpmd finds an ownerless port(just now created) by the > > > > > > > > old iterator and start traffic there, > > > > How does testpmd start traffic there? Testpmd has only a callback for > > displaying that it received an event for a new port. It has no concept > > of hotplugging beyond that. > > >=20 > Yes, so no traffic just some control command. >=20 > > Testpmd will not start using any new port probed using the hotplug API > > on its own, again, unless something has drastically changed. > > >=20 > Every iterator using in testpmd is exposed to race. >=20 > > > > > > > > - failsafe takes ownership of this new port and start traff= ic there. > > > > > > > > Problem! > > > > > > > > > > > > Could you shed a bit more light here - it would be race > > > > > > condition between whom and whom? > > > > > > > > > > Sure. > > > > > > > > > > > As I remember in testpmd all control ops are done within one > > > > > > thread (main lcore). > > > > > > > > > > But other dpdk entity can use another thread, for example: > > > > > Failsafe uses the host thread(using alarm callback) to create a > > > > > new port and > > > > to take ownership of a port. > > > > > > > > Hm, and you create new ports inside failsafe PMD, right and then > > > > set new owner_id for it? > > > > > > Yes. > > > > > > > And all this in alarm in interrupt thread? > > > > > > Yes. > > > > > > > If so I wonder how you can guarantee that no-one else will set > > > > different owner_id between > > > > rte_eth_dev_allocate() and rte_eth_dev_owner_set()? > > > > > > I check it (see failsafe patch to this series - V5). > > > Function: fs_bus_init. > > > > > > > Could you point me to that place (I am not really familiar with > > > > familiar with failsafe code)? > > > > > > > > > > > > > > The race: > > > > > Testpmd iterates over all ports by the master thread. > > > > > Failsafe takes ownership of a port by the host thread and start u= sing > it. > > > > > =3D> The two dpdk entities may use the device at same time! > > > > > > > > When can this happen? Fail-safe creates its initial pool of ports > > during EAL init, before testpmd scans eth_dev ports and configure its > streams. > > At that point, it has taken ownership, from the master lcore context. > > > > After this point, new ports could be detected and hotplugged by fail-sa= fe. > > However, even if testpmd had a callback to capture those new ports and > > reconfigure its streams, it would be executed from within the > > intr-thread, same as failsafe. If the thread was interrupted, by a > > dataplane-lcore for example, streams would not have been reconfigured. > > The fail-safe would execute its callback and set the owner-id before > > the callback chains goes to the application. > > >=20 > Some iterator may be invoked in plug out process by other thread in testp= md > and causes to control command >=20 > > And that would only be if testpmd had any callback for hotplugging > > ports and reconfiguring its streams, which it hasn't, as far as I know. > > >=20 > We don't need to implement it in testpmd. >=20 > > > > Ok, if failsafe really assigns its owner_id(s) to ports that are > > > > already in use by the app, then how such scheme supposed to work > > > > at > > all? > > > > > > If the app works well (with the new rules) it already took ownership > > > and > > failsafe will see it and will wait until the application release it. > > > Every dpdk entity should know which port it wants to manage, If 2 > > > entities want to manage the same device - it can be ok and port > > > ownership > > can synchronize the usage. > > > > > > Probably, application which will run fail-safe wants to manage only > > > the fail- > > safe port and therefor to take ownership only for it. > > > > > > > I.E. application has a port - it assigns some owner_id !=3D 0 to it= , > > > > then PMD tries to set its owner_id tot the same port. > > > > Obviously failsafe's set_owner() will always fail in such case. > > > > > > > Yes, and will try again after some time. > > > > > > > From what I hear we need to introduce a concept of 'default owner i= d'. > > > > I.E. when failsafe PMD is created - user assigns some owner_id to > > > > it > > (default). > > > > Then failsafe PMD generates it's own owner_id and assigns it only > > > > to the ports whose current owner_id is equal either 0 or 'default' > owner_id. > > > > > > > > > > It is a suggestion and we need to think about it more (I'm talking > > > about it > > with Gaetan in another thread). > > > Actually I think, if we want a generic solution to the generic > > > problem the > > current solution is ok. > > > > > > > We could as well conclude this other thread there. > > > > The only solution would be to have a default relationship between > > owners, something that goes beyond the scope assigned by Thomas to > > your evolution, but would be necessary for this API to be properly > > used by existing applications. > > > > I think it's the only way to have a sane default behavior with your > > API, but I also think this goes beyong the scope of the DPDK altogether= . > > > > But even with those considerations that could be ironed out later (API > > is still experimental anyway), in the meantime, I think we should > > strive not to break "userland" as much as possible. Meaning that > > unless you have a specific situation creating a bug, you shouldn't > > have to modify testpmd, and if an issues arises, you need to try to > > improve your API before resorting to changing the resource management > model of all existing applications. > > >=20 > I understand it. > Suggestion: >=20 > 2 system owners. > APP_OWNER - 1. > NO_OWNER - 0. >=20 > And allowing for more owners as now. >=20 > 1. Every port creation will set the owner for NO_OWNER (as now). > 2. There is option for all dpdk entities to take owner of NO_OWNER ports= all > the time(as now). > 3. In some point in the end of EAL init: set all the NO_OWNER to > APP_OWNER(for V6). > 4. Change the old iterator to iterate over APP_OWNER ports(for V6). >=20 > What do you think? >=20 > <snip>