From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id BC153A04C0; Tue, 29 Sep 2020 11:03:38 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 91A991D6F6; Tue, 29 Sep 2020 11:03:37 +0200 (CEST) Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by dpdk.org (Postfix) with ESMTP id B5ED51D6F4 for ; Tue, 29 Sep 2020 11:03:35 +0200 (CEST) IronPort-SDR: 5dHCvNl6BN3lh8eKgcpKfkke2Y48ocfXqbHIi8jh57XVo5G/UWuZ7Su7TdmRfOmE6aiXefAyuS lRGmMUjgz2OQ== X-IronPort-AV: E=McAfee;i="6000,8403,9758"; a="149804355" X-IronPort-AV: E=Sophos;i="5.77,317,1596524400"; d="scan'208";a="149804355" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Sep 2020 02:03:32 -0700 IronPort-SDR: iz+aaFSBPOb1TUn8ZVpTDz8h62X5FnBj83tTFrspGKU8v26pEGf8L5/88a+z0EjipOEP0OcnHY 3cOrp/h8Jycw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,317,1596524400"; d="scan'208";a="324607166" Received: from orsmsx606.amr.corp.intel.com ([10.22.229.19]) by orsmga002.jf.intel.com with ESMTP; 29 Sep 2020 02:03:32 -0700 Received: from orsmsx601.amr.corp.intel.com (10.22.229.14) by ORSMSX606.amr.corp.intel.com (10.22.229.19) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Tue, 29 Sep 2020 02:03:32 -0700 Received: from ORSEDG601.ED.cps.intel.com (10.7.248.6) by orsmsx601.amr.corp.intel.com (10.22.229.14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5 via Frontend Transport; Tue, 29 Sep 2020 02:03:32 -0700 Received: from NAM02-BL2-obe.outbound.protection.outlook.com (104.47.38.56) by edgegateway.intel.com (134.134.137.102) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.1713.5; Tue, 29 Sep 2020 02:03:31 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=cLQfREya8PVxtG8zsXxa9I+Nxte8jIb3pJ/5ezRHl8PGT8Iy3rRAGBmBY1T0pdcVFsSRVPAM1cqawFzU+vxcz1Q+/VisNUKWyA8sjU9HY7n8xRyqsewW7+xuypGUsEkfNHeV6l51okTNEFFo7JGyH4lIlnnzynsGTdMlCwpeQEdU39X+a9YTm5c9YiuilHr70xmUNVwwj+FQAk1ik5b1Gdvll6fyvJbt1Hy3aoqOpulK4jv7uM9cerndj4AtqIcNIlr8JsJKqIE3lov9g2cBAstgEjJRx6JKXUfoIPFByZV7unMt5t9TLKJnijWAHvk+u8+OgRHoUNOiyghgrptHcw== 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-SenderADCheck; bh=BBgyd0DJ7N6oI9mUyA6R0ycuKvTD9k+NOgQlkTCwRmU=; b=iewU2snWndbSbImJJec3m12HhFzCSwqGmrueuXPgO1BmpKINpw7rpGsFJoXE48wcHUGbi/m8sTyfDtXkCVsrynGK1r9qkT+/uP+nPGh72junCTfFm7e80rs+1ygQJQ4eNKB2PfV8WNSOnrs9tucyJDI72POxsmCVvzm145k3xixfa9h1MgRarBf+oZQR6dC3L2Hubo4XsnNZUebGvuTcYj+n75fG2BFe2ZpjcpA6ahdnGLzqxtQvEMFfLwJuWXAMjN3fdOUWjZwztk/5F/3rtKkEOQCyG72l7AFqNkqLd2eAAhBePnGnvboXuehJz04Nme2WOwoS9M/bQccCuNklCQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel.onmicrosoft.com; s=selector2-intel-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=BBgyd0DJ7N6oI9mUyA6R0ycuKvTD9k+NOgQlkTCwRmU=; b=uTWDn6jB+9oqJ2srLRasrmb3scqd/KCi8ewfzFa0SQD+VAThb9ezL12cuPGa6wMjokkCH0T1Kw9LDDF4zWxWbbu6tr1qqjGTRVA6E8Or/XAevOTXJGuU8Qqg82M6Pf/JW2GptkOkMnvSZxrMqo+2qK9huyvagf8cdhkasjay+RQ= Received: from BYAPR11MB3301.namprd11.prod.outlook.com (2603:10b6:a03:7f::26) by BYAPR11MB2677.namprd11.prod.outlook.com (2603:10b6:a02:cd::32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3412.28; Tue, 29 Sep 2020 09:03:27 +0000 Received: from BYAPR11MB3301.namprd11.prod.outlook.com ([fe80::f5a4:3f6b:ade3:296b]) by BYAPR11MB3301.namprd11.prod.outlook.com ([fe80::f5a4:3f6b:ade3:296b%3]) with mapi id 15.20.3412.026; Tue, 29 Sep 2020 09:03:27 +0000 From: "Ananyev, Konstantin" To: Honnappa Nagarahalli , "Gujjar, Abhinandan S" , "dev@dpdk.org" , "Doherty, Declan" CC: "jerinj@marvell.com" , "Akhil.goyal@nxp.com" , "Vangati, Narender" , nd , nd Thread-Topic: [dpdk-dev] [v2 1/2] cryptodev: support enqueue callback functions Thread-Index: AQHWhsTbY+pAzzKww0euN2orABmUValrRWzAgAAl9gCAAW0pMIAGJnUAgAAH/lCAAp3uAIAAgn/ggADASgCAASzNQIAHHMUAgAA/FzA= Date: Tue, 29 Sep 2020 09:03:27 +0000 Message-ID: References: <1599549024-195051-1-git-send-email-abhinandan.gujjar@intel.com> In-Reply-To: Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-reaction: no-action dlp-version: 11.5.1.3 authentication-results: arm.com; dkim=none (message not signed) header.d=none;arm.com; dmarc=none action=none header.from=intel.com; x-originating-ip: [46.7.39.127] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: e6a9f642-9360-4cdf-f345-08d864568745 x-ms-traffictypediagnostic: BYAPR11MB2677: x-ld-processed: 46c98d88-e344-4ed4-8496-4ed7712e255d,ExtAddr x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:10000; x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: DIr508a5GA9CxzX5dJFYsOOeyGIdqF7DOILaWqTK4/9U3lar57OUwDkYFaOI199SOU/pL/hrUe/VAcKtlVJOCQ+9pZkHRVpyY3y2PlkuJHA9jOBOlxpE13A9n6OkUanRA1p8PD6BS+yiTe1y1p3qbvrT2gZDNgkvQXyhj/JNVYBfyzug9q8rzkKbROQcIy8GnDI0XHTPNKHW3kJwLr2oSHH/evBkYHg4sIrQu3t8RUpHxpsrNfVXKTT6lycIDyEUtcXCx9jDvaMR66Iw1iKCIXMby0CmFIvaVKgmH/l2Qnc2vTBQnHjRd1UV7Cx+chqMmyGY6pPCbU6eL3+W2xcabBDd97FvmtaX7Pf7dMiOc/Ezh4890Z/N/xJxAKA/eanz4ZGPA51VdA4QimXYIfvxk2buWFforAqlSnAHmSb7Tj+hjN5aymxvYZvIMJDtIrA1vEIygMb1ZHRAwXPPIm85Fg== x-forefront-antispam-report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:BYAPR11MB3301.namprd11.prod.outlook.com; PTR:; CAT:NONE; SFS:(4636009)(376002)(346002)(366004)(39860400002)(136003)(396003)(6636002)(6506007)(26005)(186003)(9686003)(55016002)(66946007)(76116006)(66446008)(66476007)(66556008)(64756008)(52536014)(8676002)(71200400001)(33656002)(478600001)(966005)(7696005)(8936002)(86362001)(4326008)(54906003)(83380400001)(316002)(5660300002)(30864003)(2906002)(110136005); DIR:OUT; SFP:1102; x-ms-exchange-antispam-messagedata: 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 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: BYAPR11MB3301.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: e6a9f642-9360-4cdf-f345-08d864568745 X-MS-Exchange-CrossTenant-originalarrivaltime: 29 Sep 2020 09:03:27.0599 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: KV1GzEJO0BVr37+GOb3co26YwK3LVHXurdC+GaK9AsteMmJDCAzb0RS+YtxPbU5W2OESHrCrUvimDFos3WdnBCcYPEu3SYt8czpGumQNvOg= X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR11MB2677 X-OriginatorOrg: intel.com Subject: Re: [dpdk-dev] [v2 1/2] cryptodev: support enqueue callback functions X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Archived-At: List-Archive: >=20 > > > > > > > > > > > > > > > > > > > > > > > > > +#ifdef RTE_CRYPTODEV_CALLBACKS int > > > > > > > > > > > +rte_cryptodev_rcu_qsbr_add(uint8_t dev_id, struct > > > > > > > > > > > +rte_rcu_qsbr > > > > > > > > > > > +*qsbr) { > > > > > > > > > > > + > > > > > > > > > > > + struct rte_cryptodev *dev; > > > > > > > > > > > + > > > > > > > > > > > + if (!rte_cryptodev_pmd_is_valid_dev(dev_id)) { > > > > > > > > > > > + CDEV_LOG_ERR("Invalid dev_id=3D%" PRIu8, > > dev_id); > > > > > > > > > > > + return -EINVAL; > > > > > > > > > > > + } > > > > > > > > > > > + > > > > > > > > > > > + dev =3D &rte_crypto_devices[dev_id]; > > > > > > > > > > > + dev->qsbr =3D qsbr; > > > > > > > > > > > + return 0; > > > > > > > > > > > +} > > > > > > > > > > > > > > > > > > > > So if I understand your patch correctly you propose a > > > > > > > > > > new working model for > > > > > > > > > > crypto-devs: > > > > > > > > > > 1. Control-plane has to allocate/setup rcu_qsbr and do > > > > > > > > > > rte_cryptodev_rcu_qsbr_add(). > > > > > > > > > > 2. Data-plane has somehow to obtain pointer to that > > > > > > > > > > rcu_qsbr and wrap > > > > > > > > > > cryptodev_enqueue() > > > > > > > > > > with rcu_qsbr_quiescent() or > > > > rcu_qsbr_online()/rcu_qsbr_offline(). > > > > > > > > > Yes. I think, it is not a new model. It is same as RCU > > > > > > > > > integration with > > > > > > LPM. > > > > > > > > > Please refer: https://patches.dpdk.org/cover/73673/ > > > > > > > > > > > > > > > > I am talking about new working model for crypto-dev > > > > enqueue/dequeue. > > > > > > > > As I said above now it becomes data-plane thread responsibi= lity to: > > > > > > > > -somehow to obtain pointer to that rcu_qsbr for each > > > > > > > > cryptodev it is > > > > > > using. > > > > > > > > -call rcu sync functions (quiescent/online/offline) on a r= egular > > basis. > > > > > > > It is not on regular basis. When data plane comes up, they re= port > > online. > > > > > > > They report quiescent when they are done with critical sectio= n > > > > > > > or shared > > > > > > structure. > > > > > > > > > > > > I understand that, but it means all existing apps have to be > > > > > > changed that > > > > way. > > > > > > > > > > > > > All though, there is some dataplane changes involved here, I > > > > > > > don't think, it > > > > > > is major. > > > > > > > > > > > > I still think our goal here should be to make no visible change= s > > > > > > to the dataplane. > > > > > > I.E. all necessary data-plane changes need to be hidden inside > > > > > > CB invocation part. > > > > > Please note that this is being implemented using the memory > > > > > reclamation framework documented at > > > > > https://doc.dpdk.org/guides/prog_guide/rcu_lib.html#resource-recl= a > > > > > mati > > > > > on-framework-for-dpdk > > > > > > > > > > While using RCU there are couple of trade-offs that applications > > > > > have to > > > > consider: > > > > > 1) Performance - reporting the quiescent state too often results > > > > > in performance impact on data plane > > > > > 2) Amount of outstanding memory to reclaim - reporting less often > > > > > results in more outstanding memory to reclaim > > > > > > > > > > Hence, the quiescent state reporting is left to the application. > > > > > The application decides how often it reports the quiescent state > > > > > and has control > > > > over the data plane performance and the outstanding memory to recla= im. > > > > > > > > > > When you say "new working model for crypto-dev enqueue/dequeue", > > > > > > > > > > 1) are you comparing these with existing crypto-dev > > > > > enqueue/dequeue > > > > APIs? If yes, these are new APIs, it is not breaking anything. > > > > > 2) are you comparing these with existing call back functions in > > > > > ethdev enqueue/dequeue APIs? If yes, agree that this is a new > > > > > model. But, it is > > > > possible to support what ethdev supports along with the RCU method > > > > used in this patch. > > > > > > > > What I am talking about: > > > > > > > > Existing cryptodev enqueue/dequeue model doesn't require for the > > > > user to manage any RCU QSBR state manually. > > > > I believe that addition of ability to add/remove enqueue/dequeue > > > > callbacks shouldn't change existing working model. > > > > I think that adding/removing such callbacks has to be opaque to the > > > > user DP code and shouldn't require user to change it. Same as we > > > > have now for ethdev callback implementation. > > > The ethdev callback implementation conveniently leaves the problem of > > freeing memory to the user to resolve, it does not handle the issue. > > > Hence, it "looks" to be opaque to the DP code. However, if the > > > application has to implement a safe way to free the call back memory,= its > > DP is affected based on call backs are being used or not. > > > > Yes, I think that's big drawback in initial ethdev callback implementat= ion - it > > simply ignores DP/CP sync problem completely. > > Though I think it is possible to have both here: > > keep callback "opaque" to DP code and provide some sync mechanism > > between DP/CP. > > Hopefully one day we can fix ethdev callbacks too. > The solution we develop can be used in ethdev too. >=20 > > > > > > I think that forcing DP code to be aware that callbacks are present > > > > or not and to modify its behaviour depending on that nearly voids > > > > the purpose of having callbacks at all. > > > > In that case DP can just invoke callback function directly from it'= s > > codepath . > > > > > > > > > > > > > > > > > > > > > > > > > Note that now data-plane thread would have to do that alway= s > > > > > > > > - even if there are now callbacks installed for that > > > > > > > > cryptodev queue > > > > right now. > > > > > > > > All that changes behaviour of existing apps and I presume > > > > > > > > would reduce adoption of that fature. > > > > > If I understand this correct, you are talking about a case where > > > > > in the application might be registering/unregistering multiple > > > > > times during its lifetime. In this case, yes, the application > > > > > might be reporting the > > > > quiescent state even when it has not registered the call backs. But= , > > > > it has the flexibility to not report it if it implements additional= logic. > > > > > Note that we are assuming that the application has to report > > > > > quiescent state only for using callback functions. Most probably > > > > > the application has > > > > other requirements to use RCU. > > > > > Why not support what is done for ethdev call back functions along > > > > > with > > > > providing RCU method? > > > > > > > > > > > > There is always trade off involved! > > > > > > > In the previous patch, you suggested that some lazy app may > > > > > > > not free up the memory allocated by add cb. For such apps, > > > > > > > this patch has sync mechanism with some additional cost of CP= & DP > > changes. > > > > > > > > > > > > Sigh, it is not about laziness of the app. > > > > > > The problem with current ethedev cb mechanism and yours V1 > > > > > > (which was just a clone of it) - CP doesn't know when it is saf= e > > > > > > after CB removal to free related memory. > > > > > > > > > > > > > > I still think all this callback mechanism should be totally > > > > > > > > opaque to data-plane threads - user shouldn't change his ap= p > > > > > > > > code depending on would some enqueue/dequeue callbacks be > > > > installed or not. > > > > > > > I am not sure, how that can be implemented with existing RCU > > design. > > > > > > > > > > > > As I said below the simplest way - with calling rcu > > > > > > onine/offline inside CB invocation block. > > > > > > That's why I asked you - did you try that approach and what is > > > > > > the perf numbers? > > > > > > I presume with no callbacks installed the perf change should be > > > > > > nearly > > > > zero. > > > > > > > > > > > > > @Honnappa Nagarahalli, Do you have any suggestions? > > > > > Reporting quiescent state in the call back functions has several > > > > disadvantages: > > > > > 1) it will have performance impacts and the impacts will increase > > > > > as the > > > > number of data plane threads increase. > > > > > 2) It will require additional configuration parameters to control > > > > > how often the quiescent state is reported to control the performa= nce > > impact. > > > > > 3) Does not take advantage of the fact that most probably the > > > > > application is using RCU already > > > > > 4) There are few difficulties as well, please see below. > > > > > > > > I suggested Abhinandan to use RCU library because it is already > > > > there, and I thought it would be good not to re-implement the wheel= . > > > > Though if you feel librte_rcu doesn't match that task - fine, let's > > > > do it without librte_rcu. > > > > After all, what we need here - just an atomic ref count per queue > > > > that we are going to increment at entering and leaving list of > > > > callbacks inside enqueue/dequeue. > > > Ok, looks like I missed the point that a queue is used by a single da= ta plane > > thread. > > > Along with ref count increment you need the memory orderings to avoid > > race conditions. These will be the same ones used in RCU. > > > On the control plane, you need to read this counter and poll for the > > counter updates. All this is same cost as in RCU. > > > > Agree. > > > > > To control the cost, you > > > will have to control the rate of quiescent state reporting and might = have to > > expose this as a configuration parameter. > > > > > > The other important information you have to consider is if the thread > > > is making any blocking calls, which may be in some other library. The > > > thread is supposed to call rcu_qsbr_thread_offline API before calling= a > > blocking call. This allows the RCU to know that this particular thread = will not > > report quiescent state. The cryptodev library might not have that infor= mation. > > > > > > If you want to go ahead with this design, you can still use RCU with > > > single thread configuration (like you have mentioned below) and hide = the > > details from the application. > > > > Yes, same thought here - use rcu_qsbr online/offline for DP part and = hide > > actual sync details inside callback code. > We can give it a try. If we can have the performance numbers, we can deci= de about how to control how often these APIs are called on the > data plane. To avoid misunderstanding: I am talking about calling online/offline with every cryptodev_enqueue() traversal over CB list. >=20 > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > That seems quite a big change and I don't think it is > > > > > > > > > > acceptable for most users. > > > > > > > > > > From my perspective adding/installing call-backs to the > > > > > > > > > > dev has to be opaque to the data-plane code. > > > > > > > > > > Also note that different callbacks can be installed by > > > > > > > > > > different entities (libs) and might have no idea about = each > > other. > > > > > > > > > > That's why I thought it would be better to make all thi= s > > > > > > > > > > RCU stuff internal inside cryptodev: > > > > > > > > > > hide all this rcu_qsbr allocation/setup inside > > > > > > > > > > cryptod somehow to > > > > > > > > obtain pointer to that rcu_qsbr ev init/queue setup > > > > > > > > > > invoke rcu_qsbr_online()/rcu_qsbr_offline() inside > > > > > > > > cryptodev_enqueue(). > > > > > This will bring in the application related information such as th= e > > > > > thread ID > > > > into the library. > > > > > > > > I don't think it would. > > > > Cryptodev enqueue/dequeue functions are not supposed to be thread > > > > safe (same as rx/tx burst). > > > > So we can always use RCU with just one thread(thread_id =3D 0). > > > Agree, the memory that needs to be freed is accessed by a single thre= ad > > on the data plane. RCU with one thread would suffice. > > > > > > > But as I said above - if you feel RCU lib is an overhead here, > > > > that's fine - I think it would be easy enough to do without librte_= rcu. > > > > > > > > > If the same API calls are being made from multiple data plane > > > > > threads, you need a way to configure that information to the > > > > > library. So, it is better to leave those details for the applicat= ion to handle. > > > > > > > > > > > > > > I have already tried exploring above stuffs. There are to= o > > > > > > > > > many > > > > > > constraints. > > > > > > > > > The changes don't fit in, as per RCU design. > > > > > > > > > > > > > > > > Hmm could you be more specific here - what constraints are > > > > > > > > you referring to? > > > > > > > > > > > > > > > > > Moreover, having rcu api under enqueue_burst() will affec= t > > > > > > > > > the > > > > > > > > performance. > > > > > > > > > > > > > > > > It most likely will. Though my expectation it will affect > > > > > > > > performance only when some callbacks are installed. My > > > > > > > > thought > > > > here: > > > > > > > > callback function by itself will affect cryptdev_enqueue > > > > > > > > performance anyway, > > > > > > > With existing callback design, I have measured the > > > > > > > performance(with > > > > > > crypto perf test) on xeon. > > > > > > > It was almost negligible and same was shared with Declan. > > > > > > > > > > > > I am asking about different thing: did you try alternate > > > > > > approach I described, that wouldn't require changes in the user= data- > > plane code. > > > > > > > > > > > > > That is one of the reasons, I didn't want to add to many > > > > > > > stuffs in to the > > > > > > callback. > > > > > > > The best part of existing design is crypto lib is not much mo= dified. > > > > > > > The changes are either pushed to CP or DP. > > > > > > > > > > > > > > so adding extra overhead for sync is probably ok here. > > > > > > > > > > > > I think that extra overhead when callbacks are present is > > > > > > expected and probably acceptable. > > > > > > Changes in the upper-layer data-plane code - probably not. > > > > > > > > > > > > > > Though for situation when no callbacks are installed - > > > > > > > > perfomance should be left unaffected (or impact should be a= s > > > > > > > > small > > > > as possible). > > > > > > > > > > > > > > > > > The changes are more on control plane side, which is one = time. > > > > > > > > > The data plane changes are minimal. > > > > > > > > > > > > > > > > I still think upper layer data-plane code should stay > > > > > > > > unaffected (zero changes). > > > > > > > > > > > > > > > > > > > > > > > >