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

[Ray Kinsella <mdr@ashroe.eu>]

On 08/04/2019 14:38, Burakov, Anatoly wrote:
> On 08-Apr-19 2:00 PM, Ray Kinsella wrote:
>>
>>
>> On 08/04/2019 11:15, Burakov, Anatoly wrote:
>>> On 08-Apr-19 10:04 AM, Ray Kinsella wrote:
>>>> On 07/04/2019 10:48, Thomas Monjalon wrote:
>>>>> 04/04/2019 16:07, Burakov, Anatoly:
>>>>>> On 04-Apr-19 1:52 PM, Ray Kinsella wrote:
>>>>>>> On 04/04/2019 11:54, 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:
>>>> [SNIP]
>> [SNIP]
[SNIP]
>>
> 
> Perhaps i didn't phrase myself well enough. When i say "DPDK 1.0
> specification" i don't mean there literally should be a document with a
> formal specification :)

When I hear the word specification I think encyclopedia-like stacks of
paper.

> 
> Rather, i'm thinking more along the lines of, let's take a look at what
> we have, and think of ways we can reduce the amount of code and improve
> things without causing major inconveniences to great majority of users.
> As in, if we want to "break once more and then never again", then maybe
> instead of small incremental fixes here and there, we could actually do
> a more drastic change that keeps perhaps 90% users happy instead of
> 100%, but which reduces maintenance/validation effort from 100% down to
> 30%.

Agreed - all I would propose on top of this is that we give ourselves a
real deadline.

The DPDK API has been iterating since 2012 and while we can spare a few
more months to do tidy-up and get it right, we _do_ need to draw a line
in the sand at the same time.

> 
> As a concrete proposal, my number one dream would be to see multiprocess
> gone. I also recall desire for "DPDK to be more lightweight", and i
> maintain that DPDK *cannot* be lightweight if we are to support
> multiprocess - we can have one or the other, but not both. However,
> realistically, i don't think dropping multiprocess is ever going to
> happen - not only it is too entrenched in DPDK use cases, it is actually
> quite useful despite its flaws.
> 
> However, what *could* be realistic is to trim down complexity in EAL
> init and system code in general - to me (again, a concrete proposal!),
> that would be dropping igb_uio and supporting upstream kernel modules
> only (VFIO, maybe uio_pci_generic if we're pushing it?), dropping 32-bit
> support and legacy mem modes, and perhaps bumping kernel version and
> removing some compatibility code as well. This would remove potentially
> thousands of lines of code and keep EAL cleaner and more maintainable:
> right now, we have two different hotplug mechanisms (UIO and VFIO), lots
> of different memory/interrupt modes, etc., for no reason that is readily
> apparent to me.
> 
> So, as you can see, an effort to review and delineate what we want to
> support would be necessary if we want to ease the maintenance burden for
> either myself or anyone that inherits this code, as well as reducing the
> number of moving parts and, as a consequence, validation effort and
> amount of bugs. We can't simply do it in a random release "just
> because", but if we were to "break once more and then never again",
> perhaps this is something that could be considered.
>