Re: [dpdk-dev] [dpdk-techboard] DPDK ABI/API Stability

[Thomas Monjalon <thomas@monjalon.net>]

05/04/2019 15:25, Ray Kinsella:
> On 04/04/2019 14:10, Bruce Richardson wrote:
> > On Thu, Apr 04, 2019 at 02:05:27PM +0100, Ray Kinsella wrote:
> >> On 04/04/2019 13:02, Luca Boccassi wrote:
> >>> On Thu, 2019-04-04 at 11:54 +0100, Bruce Richardson wrote:
> >>>> On Thu, Apr 04, 2019 at 10:29:19AM +0100, Burakov, Anatoly wrote:
> >>>>> On 03-Apr-19 4:42 PM, Ray Kinsella wrote:
> >>
> > I would be too, with certain exceptions - rte_mbuf for one. Any structures
> > that are used by applications cannot be made opaque, as apps do not want to
> > pay the cost of having to call a function every time they want to access
> > something from one of those structures.
> 
> These the layout of these structures really must become sacrosanct.
> As Stephen points out, there may be room for a one more change - fool me
> once - to future poof the structure but after, that these structure will
> become very hard to change.

Yes, looks like a good plan.

> > Thankfully for us, we have plenty of other structures that we can work on
> > in the meantime that can be made private to avoid ABI breaks! :-) I suggest
> > we work through those first, allowing us to hone our ABI-break avoidance
> > skills.

+1 to work on obvious cases first.

I think we should not wait too much to improve mbuf
with some dynamically registered fields, because it may be
long to achieve such an important feature and make everybody happy.
Note: we may have to sacrifice a few cycles for some features
like distributor or IPsec.