From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Iremonger, Bernard" <bernard.iremonger@intel.com>
Subject: Re: [RFC PATCH v2 3/5] librte_ether: add API's for VF
 management
Date: Wed, 28 Sep 2016 15:24:37 +0000
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Cc: "dev@dpdk.org" <dev@dpdk.org>, "Ananyev, Konstantin"
 <konstantin.ananyev@intel.com>, "Richardson, Bruce"
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 "Shah, Rahul R" <rahul.r.shah@intel.com>, "Lu, Wenzhuo"
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To: Thomas Monjalon <thomas.monjalon@6wind.com>
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Hi Thomas,

<snip>

> -----Original Message-----
> Subject: Re: [dpdk-dev] [RFC PATCH v2 3/5] librte_ether: add API's for VF
> management
>=20
> 2016-09-28 14:48, Iremonger, Bernard:
> > <snip>
> >
> > > > Subject: Re: [dpdk-dev] [RFC PATCH v2 3/5] librte_ether: add API's
> > > > for VF management
> > > >
> > > > 2016-09-28 13:26, Ananyev, Konstantin:
> > > > > From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> > > > > > 2016-09-28 11:23, Ananyev, Konstantin:
> > > > > > > If we  this way (force user to include driver specific
> > > > > > > headers and call driver specific functions), how you guys
> > > > > > > plan to make this
> > > functionality available for multiple driver types.
> > > > > >
> > > > > > Multiple drivers won't have exactly the same specific features.
> > > > > > But yes, there are some things common to several Intel NICs.
> > > > > >
> > > > > > > From discussion with Bernard  understand that customers
> > > > > > > would
> > > need similar functionality for i40e.
> > > > > > > Does it mean that they'll have to re-implement this part of
> > > > > > > their code
> > > again?
> > > > > > > Or would have to create (and maintain) their own shim layer
> > > > > > > that
> > > would provide some s of abstraction?
> > > > > > > Basically their own version of rte_ethdev?
> > > > > >
> > > > > > No definitive answer.
> > > > > > But we can argue the contrary: how to handle a generic API
> > > > > > which is implemented only in 1 or 2 drivers? If the
> > > > > > application tries to use it,
> > > we can imagine that a specific range of hardware is expected.
> > > > >
> > > > > Yes, as I understand, it is a specific subset of supported HW
> > > > > (just Inel NICs
> > > for now, but different models/drivers).
> > > > > Obviously users would like to have an ability to run their app
> > > > > on all HW
> > > from this subset without rebuilding/implementing the app.
> > > > >
> > > > > >
> > > > > > I think it is an important question.
> > > > > > Previously we had the issue of having some API which are too
> > > > > > specific and need a rework to be used with other NICs. In
> > > > > > order to avoid such rework and API break, we can try to make
> > > > > > them available in a driver-specific or vendor-specific staging
> > > > > > area, waiting for
> > > > a later generalization.
> > > > >
> > > > > Could you remind me why you guys were that opposed to ioctl
> > > > > style
> > > approach?
> > > > > It is not my favorite thing either, but it seems pretty generic
> > > > > way to
> > > handle such situations.
> > > >
> > > > We prefer having well-defined functions instead of opaque
> > > > ioctl-style
> > > encoding.
> > > > And it was not clear what is the benefit of ioctl.
> > > > Now I think I understand you would like to have a common ioctl
> > > > service for
> > > features available on 2 drivers. Right?
> > >
> > > Yes.
> > >
> > > > Example (trying to  read your mind):
> > > > 	rte_ethdev_ioctl(port_id, <TLV encoding VF_PING service and VF
> > > id>); instead of
> > > > 	rte_pmd_ixgbe_vf_ping(port_id, vf_id);
> > > > 	rte_pmd_i40e_vf_ping(port_id, vf_id); Please confirm I understand
> > > > what you are thinking about.
> > >
> > > Yep, you read my mind correctly :)
> > > Konstantin
> > >
> > Adding the pmd_ops field to struct eth_devops {} discussed previously i=
n
> this email thread will allow driver specific functions for multiple drive=
rs and
> will get rid of the driver specific header file rte_pmd_driver.h.
> > Would this be an acceptable solution?
>=20
> How pmd_ops would be different of eth_devops?

There is not a lot of difference, however it would separate generic ethdev =
functions from driver specific functions.

Regards,

Bernard.