From:   "Chen, Mike Ximing" <mike.ximing.chen@intel.com>
To:     Andrew Lunn <andrew@lunn.ch>
CC:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "arnd@arndb.de" <arnd@arndb.de>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "Williams, Dan J" <dan.j.williams@intel.com>,
        "pierre-louis.bossart@linux.intel.com" 
        <pierre-louis.bossart@linux.intel.com>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "davem@davemloft.net" <davem@davemloft.net>,
        "kuba@kernel.org" <kuba@kernel.org>
Subject: RE: [RFC PATCH v12 01/17] dlb: add skeleton for DLB driver
Thread-Topic: [RFC PATCH v12 01/17] dlb: add skeleton for DLB driver
Thread-Index: AQHX9jcKOP1y1O92CEC3pIeygh1pI6w8tNAAgACRSSCAADPkgIAABxaggAGHswCAAHiSsA==
Date:   Thu, 23 Dec 2021 05:15:34 +0000
Message-ID: <CO1PR11MB5170B7667FD1C091E1946CEDD97E9@CO1PR11MB5170.namprd11.prod.outlook.com>
References: <20211221065047.290182-1-mike.ximing.chen@intel.com>
 <20211221065047.290182-2-mike.ximing.chen@intel.com>
 <YcGkILZxGLEUVVgU@lunn.ch>
 <CO1PR11MB51705AE8B072576F31FEC18CD97C9@CO1PR11MB5170.namprd11.prod.outlook.com>
 <YcJJh9e2QCJOoEB/@lunn.ch>
 <CO1PR11MB5170C1925DFB4BFE4B7819F5D97C9@CO1PR11MB5170.namprd11.prod.outlook.com>
 <YcOYDi1s5x5gU/5w@lunn.ch>
In-Reply-To: <YcOYDi1s5x5gU/5w@lunn.ch>
Accept-Language: en-US
Content-Language: en-US
dlp-version: 11.6.200.16
dlp-reaction: no-action
dlp-product: dlpe-windows
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?rnzr/9uoE1u3F9PnwOt+KS50fcIpgIUAKj0ytWPOfWrzW1F+wJ+u1IS2axQe?=
 =?us-ascii?Q?jGWQo4fSyhsFOUb0iuzmJIHlp5nS/kBc3hdoy9SqxpNC/pZsSucSdkO/fvar?=
 =?us-ascii?Q?ECnSXta93R/bzg+Ndp4VwwZ42lZ4/z/4JlB1rPdYrjKJ5EKv+SETYGmN8z3w?=
 =?us-ascii?Q?C0c41mXjHp3k5g2cnRc43Sgk833S0wqEljdELhLsKZEjm6q4cEQF1x8w2Z6o?=
 =?us-ascii?Q?0Av8kmLOwjICOh9b846v3uM9N8E+XgOAnXmwqXZVlL9ExVxzHgsxwclq3Lq+?=
 =?us-ascii?Q?sKQCE0kl7lXrcYbv3zzemF/YlZNPEs1Mv+WPeIWIOFlEOp0g+XBrfyrtiTC4?=
 =?us-ascii?Q?/PWJpmoEAeTBl9BlPMATOJsgEAGP5F7QESymOcmK51OUrfxRDsUe/KyyB3nF?=
 =?us-ascii?Q?bZw0vSiSQcxcVD1YpMqhh6JGz3sgJ6IZ3M+0RtRlMtHkmEeKu3dTNfv/ywDV?=
 =?us-ascii?Q?FNbD51pXXWQJUqHC0nMkc2x3Xdlu9EfmtdWqXoMfXo5bIxZZUHURg1DxjEl2?=
 =?us-ascii?Q?KHc06+z3428YHUGM5B+tdI4uXJQP8Vrc4eMBXvireSkdsaV7e1+2337rsoii?=
 =?us-ascii?Q?sUodC3mnIyKWBbHnkYQponHomEMET0JWbDHWp4FAqT+NksGidpTh93YkGmF/?=
 =?us-ascii?Q?hmeBb7YQveva2s9Y9LCWNuPb0O0JKtLvfLZplX1ArQYWQUUnqHdFq7eu3kUs?=
 =?us-ascii?Q?Q67+xmGnGVBTnqPiC5VdB2f1orxMJJ3vDYgADVxsZFG3oQK2+lIx7Zc24og/?=
 =?us-ascii?Q?VTOxJBj30nCDH8IRiyufDevU9DyrbAiOUaivlzuGla9ST44BNRK224QLxJU8?=
 =?us-ascii?Q?hm33qIZ+1hlxNFrZsMn/B8rV/K1qcqQ1nDeTx5eC+zxPnpD4YfO6TZgbUlxk?=
 =?us-ascii?Q?h0nB7lhRQqABbSMwCcefiH9YMq4BpL+XsHtDbhhVECTrrGi/0QzWxQ3TFc1K?=
 =?us-ascii?Q?7cPheK9+ZiNQqRKraWVxQdtim+FV1Seuh5mdbZnG/BZXSlPIh237o3qiDN5F?=
 =?us-ascii?Q?Dblk/l2l0Tt3A9HZxsUWZZFfbc46l56NCw90OfbBsFlXpre0OcZtUJCeCmuJ?=
 =?us-ascii?Q?1Eix3TeT5sS1TjG9Pe/Fx1BKYzs2VuCZv7OXWnMk9K2UxkeQBAri1SQxmhLW?=
 =?us-ascii?Q?Y6xG0C/2YVD4v27crEWm7fCvJiivJ6e3ydNzCv86fTgPMxsu85yX1XrP63FZ?=
 =?us-ascii?Q?ULUO14BV4lNHxmRPwPb5A5njY7pDTyyXLw45ww/DulJ/jMciWDWWWA1FNayI?=
 =?us-ascii?Q?9roMbXV5CTPKz7ShuOLHa1vHO27qrnpfO+r8amkiwVtsi+CYYCWtPK/lFzcx?=
 =?us-ascii?Q?6gbzx7jydIcJnlslBoRwuwsQNNvPJptiWlq6xeB6m7PcK2CVcVW/on++Le9m?=
 =?us-ascii?Q?t84EteOKuhSrexqtgyGbi6BdUatFIBLUYSfmmAhop86dhk4YQt8n9CFuEsqZ?=
 =?us-ascii?Q?z7NFtuIL5psBgNL3QP0qZl1RKfCaE1hG0bvvhwLzP4RCFp8dkzdUpuX38GpD?=
 =?us-ascii?Q?VOcBKOVw3VMHsGt+ZKGxvh1+RHKPJHib7aMb8dwHjQIyDEUkvpv3UVQk8hHY?=
 =?us-ascii?Q?kfUsDaCvK0h5YeDex5z3BLCjFNIuMMLIP4yRJBoBEzDgrWwSiRNkYB4kfoqq?=
 =?us-ascii?Q?ulV93sNu7h/+QotDGZuFermXfnxxAd7SQZcWg1MWQJg1MmHcjeWPZeOBru7A?=
 =?us-ascii?Q?F6BXBg=3D=3D?=
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: CO1PR11MB5170.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: d3cd59d5-5fb9-40af-65ff-08d9c5d33fef
X-MS-Exchange-CrossTenant-originalarrivaltime: 23 Dec 2021 05:15:34.9886
 (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: ks122s1cIdO4GWrd0LWtdVd1qbssECyKT8fbZo9BsP6wADZJ50Y3XNom4elLbbz3TUiNkLs6pNAMYqSSf0/tQZCEHs/YWwCuPY20CzzZRxU=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR1101MB2240
X-OriginatorOrg: intel.com
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


> -----Original Message-----
> From: Andrew Lunn <andrew@lunn.ch>
> Sent: Wednesday, December 22, 2021 4:27 PM
> To: Chen, Mike Ximing <mike.ximing.chen@intel.com>
> Cc: linux-kernel@vger.kernel.org; arnd@arndb.de; gregkh@linuxfoundation.o=
rg; Williams, Dan J
> <dan.j.williams@intel.com>; pierre-louis.bossart@linux.intel.com; netdev@=
vger.kernel.org;
> davem@davemloft.net; kuba@kernel.org
> Subject: Re: [RFC PATCH v12 01/17] dlb: add skeleton for DLB driver
>=20
> > > pointing to skbufs? How are the lifetimes of skbufs managed? How do
> > > you get skbufs out of the NIC? Are you using XDP?
> >
> > This is not a network accelerator in the sense that it does not have
> > direct access to the network sockets/ports. We do not use XDP.
>=20
> So not using XDP is a problem. I looked at previous versions of this patc=
h, and it is all DPDK. But DPDK is
> not in mainline, XDP is. In order for this to be merged into mainline you=
 need a mainline user of it.
>=20
> Maybe you should abandon mainline, and just get this driver merged into t=
he DPDK fork of Linux?
>=20
Hi Andrew,

I am not sure why not using XDP is a problem. As mentioned earlier, the
DLB driver is not a part of network stack. =20

DPDK is one of applications that can make a good use of DLB, but is not the
only one. We have applications that access DLB directly via the kernel driv=
er API
without using DPDK. Even in a DPDK application, the only part that involves
DLB is the eventdev poll mod driver module, in which we can replace a
traditional software base queue manager with DLB. The network access and
receiving/transmitting data from/to NIC is, on the other hand, handled by
the ethdev in DPDK. The eventdev (and DLB) distributes packet processing
over multiple worker cores.

Thanks
Mike