Re: [dpdk-dev] [PATCH v13 2/5] eal: add the APIs to wait until equal

[David Marchand <david.marchand@redhat.com>]

On Tue, Dec 10, 2019 at 8:52 AM Honnappa Nagarahalli
<Honnappa.Nagarahalli@arm.com> wrote:
> > > > > > Again I suppose they might be re-used in future some other ARM
> > > specific low-level primitvies.
> > > > >
> > > > > Do this low-level routines _LOAD_EXC_ need to be exposed in EAL
> > > > > for re-
> > > use?
> > > >
> > > > About load_exc don't know for sure...
> > > > Though as I can see wfe/sevl are used here:
> > > > http://patchwork.dpdk.org/patch/61779/
> > > > Might be it is possible to reuse these functions/macros...
> > > > But again, I am not arm expert, would be interested to know what arm
> > > guys think.
> > >
> > >
> > > Considering WFE has a requirement on using load_exec on ARM so IMO, it
> > > makes sense to expose load_exec in conjunction with wfe/sevl to use it
> > > properly.
> > Agree, WFE should have more use cases can be developed, not limited to the
> > WAIT_UNTIL_EQUAL_XX APIs. Marvel's patch is an example.
> > Sorry I don't have more use case so far, but Arm is evolving WFE, so I think
> > more use cases are emerging.
> > /Gavin
> I think the focus of this patch is 'rte_wait_until_equal_xxx' APIs. I would say, this patch serves that purpose as we all agree on the definition of the APIs.
> The implementation of the API may be conservative, but I think it is alright as it does not bind us from changing it in the future. We can look at further use cases as and when they come.

Sorry for being so long to work on this.

We discussed this in december with Honnappa.
The main point that transpired is that there is no other usecase for
wfe/sevl/loadex block than the rte_wait_until_equal APIs.

I then intend to stick to the last version I sent, which only exposes
these APIs and hides all the other details.

If we need to expose those blocks for new usecases, then we will
rediscuss the APIs.

I will merge this series tomorrow so that it makes it into 20.02-rc1.
If there are strong oppositions to my last changes, we can have
followup patches on the implementation, the exposed APIs will be the
same anyway.

Thanks.


-- 
David Marchand