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From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: "Dumitrescu, Cristian" <cristian.dumitrescu@intel.com>
Cc: dev@dpdk.org,
	"jerin.jacob@caviumnetworks.com" <jerin.jacob@caviumnetworks.com>,
	"balasubramanian.manoharan@cavium.com"
	<balasubramanian.manoharan@cavium.com>,
	"hemant.agrawal@nxp.com" <hemant.agrawal@nxp.com>,
	"shreyansh.jain@nxp.com" <shreyansh.jain@nxp.com>,
	"Wiles, Keith" <keith.wiles@intel.com>,
	"Richardson, Bruce" <bruce.richardson@intel.com>
Subject: Re: [dpdk-dev] [PATCH v3 1/2] ethdev: add capability control API
Date: Mon, 06 Mar 2017 21:21:33 +0100	[thread overview]
Message-ID: <10140076.z0k8vql8dv@xps13> (raw)
In-Reply-To: <3EB4FA525960D640B5BDFFD6A3D891265275B202@IRSMSX108.ger.corp.intel.com>

> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> > 2017-03-06 16:35, Dumitrescu, Cristian:
> > > > > +int rte_eth_dev_capability_ops_get(uint8_t port_id,
> > > > > +	enum rte_eth_capability cap, void *arg);
> > > >
> > > > What is the benefit of getting different kind of capabilities with
> > > > the same function?
> > > > enum + void* = ioctl
> > > > A self-explanatory API should have a dedicated function for each kind
> > > > of features with different argument types.
> > >
> > > The advantage is providing a standard interface to query the capabilities of
> > the device rather than having each capability provide its own mechanism in a
> > slightly different way.
> > >
> > > IMO this mechanism is of great help to guide the developers of future
> > ethdev features on the clean path to add new features in a modular way,
> > extending the ethdev functionality while doing so in a separate name space
> > and file (that's why I tend to call this a plugin-like mechanism), as opposed to
> > the current monolithic approach for ethdev, where we have 100+ API
> > functions in a single name space and that are split into functional groups just
> > by blank lines in the header file. It is simply the generalization of the
> > mechanism introduced by rte_flow in release 17.02 (so all the credit should
> > go to Adrien and not me).
> > >
> > > IMO, having a standard function as above it cleaner than having a separate
> > and slightly different function per feature. People can quickly see the set of
> > standard ethdev capabilities and which ones are supported by a specific
> > device. Between A) and B) below, I definitely prefer A):
> > > A) status = rte_eth_dev_capability_ops_get(port_id,
> > RTE_ETH_CABABILITY_TM, &tm_ops);
> > > B) status = rte_eth_dev_tm_ops_get(port_id, &tm_ops);
> > 
> > I prefer B because instead of tm_ops, you can use some specific tm
> > arguments,
> > show their types and properly document each parameter.
> 
> Note that rte_flow already returns the flow ops as a void * with no strong argument type checking (approach A from above). Are you saying this is wrong?
> 
> 	rte_eth_dev_filter_ctrl(port_id, RTE_ETH_FILTER_GENERIC, RTE_ETH_FILTER_GET, void *eth_flow_ops);
> 
> Personally, I am in favour of allowing the standard interface at the expense of strong build-time type checking. Especially that this API function is between ethdev and the drivers, as opposed to between app and ethdev.

rte_eth_dev_filter_ctrl is going to be specialized in rte_flow operations.
I agree with you on having independent API blocks in ethdev like rte_flow.
But this function rte_eth_dev_capability_ops_get that you propose would be
cross-blocks. I don't see the benefit.
I especially don't think there is a sense in the enum
	enum rte_eth_capability {
		RTE_ETH_CAPABILITY_FLOW = 0, /**< Flow */
		RTE_ETH_CAPABILITY_TM, /**< Traffic Manager */
		RTE_ETH_CAPABILITY_MAX
	}

I won't debate more on this. We have to read opinions of other reviewers.

  reply	other threads:[~2017-03-06 20:21 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-04  1:10 [dpdk-dev] [PATCH v3 0/2] ethdev: abstraction layer for QoS hierarchical scheduler Cristian Dumitrescu
2017-03-04  1:10 ` [dpdk-dev] [PATCH v3 1/2] ethdev: add capability control API Cristian Dumitrescu
2017-03-06 10:32   ` Thomas Monjalon
2017-03-06 16:35     ` Dumitrescu, Cristian
2017-03-06 16:57       ` Thomas Monjalon
2017-03-06 18:28         ` Dumitrescu, Cristian
2017-03-06 20:21           ` Thomas Monjalon [this message]
2017-03-06 20:41             ` Wiles, Keith
2017-03-06 20:54               ` Stephen Hemminger
2017-03-07 10:14                 ` Dumitrescu, Cristian
2017-03-07 12:56                   ` Thomas Monjalon
2017-03-07 19:17                     ` Wiles, Keith
2017-03-06 16:36     ` Dumitrescu, Cristian
2017-05-19 17:12   ` [dpdk-dev] [PATCH v4 0/2] ethdev: abstraction layer for QoS traffic management Cristian Dumitrescu
2017-05-19 17:12     ` [dpdk-dev] [PATCH v4 1/2] ethdev: add traffic management ops get API Cristian Dumitrescu
2017-06-09 16:51       ` [dpdk-dev] [PATCH v5 0/2] ethdev: abstraction layer for QoS traffic management Cristian Dumitrescu
2017-06-09 16:51         ` [dpdk-dev] [PATCH v5 1/2] ethdev: add traffic management ops get API Cristian Dumitrescu
2017-06-09 16:51         ` [dpdk-dev] [PATCH v5 2/2] ethdev: add traffic management API Cristian Dumitrescu
2017-06-12  3:36           ` Jerin Jacob
2017-06-12 10:24             ` Dumitrescu, Cristian
2017-06-12 13:35           ` [dpdk-dev] [PATCH v6 0/2] ethdev: abstraction layer for QoS traffic management Cristian Dumitrescu
2017-06-12 13:35             ` [dpdk-dev] [PATCH v6 1/2] ethdev: add traffic management ops get API Cristian Dumitrescu
2017-06-12 13:35             ` [dpdk-dev] [PATCH v6 2/2] ethdev: add traffic management API Cristian Dumitrescu
2017-06-27 13:24             ` [dpdk-dev] [PATCH v6 0/2] ethdev: abstraction layer for QoS traffic management Dumitrescu, Cristian
2017-05-19 17:12     ` [dpdk-dev] [PATCH v4 2/2] ethdev: add traffic management API Cristian Dumitrescu
2017-05-19 17:34       ` Stephen Hemminger
2017-05-22 14:25         ` Dumitrescu, Cristian
2017-05-24 11:28       ` Hemant Agrawal
2017-05-31 13:45       ` Jerin Jacob
2017-05-31 17:05         ` Manoharan, Balasubramanian
2017-03-04  1:10 ` [dpdk-dev] [PATCH v3 2/2] ethdev: add hierarchical scheduler API Cristian Dumitrescu
2017-03-06 10:38   ` Thomas Monjalon
2017-03-06 16:59     ` Dumitrescu, Cristian
2017-03-06 20:07       ` Thomas Monjalon
2017-03-07 19:29         ` Dumitrescu, Cristian
2017-03-08  9:51           ` O'Driscoll, Tim
2017-03-10 18:37             ` Dumitrescu, Cristian
2017-03-15 12:43               ` Thomas Monjalon
2017-03-16 16:23                 ` Dumitrescu, Cristian
2017-03-16 17:29                   ` Thomas Monjalon
2017-03-16 17:40                     ` Dumitrescu, Cristian
2017-03-16 18:10                       ` Thomas Monjalon
2017-03-16 19:06                         ` Dumitrescu, Cristian
2017-03-24 19:55                           ` Dumitrescu, Cristian
2017-03-06 16:15   ` Stephen Hemminger
2017-03-06 18:17     ` Dumitrescu, Cristian
2017-03-16 17:35   ` Thomas Monjalon
2017-03-30 10:32   ` Hemant Agrawal
2017-04-07 16:51     ` Dumitrescu, Cristian
2017-04-07 13:20   ` Jerin Jacob
2017-04-07 17:47     ` Dumitrescu, Cristian
2017-04-10 14:00       ` Jerin Jacob

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