Re: [dpdk-dev] [PATCH] eal:ppc: fix incorrect ifdef for ppc_64

[David Christensen <drc@linux.vnet.ibm.com>]

>>>> The change itself is not that scary, but just reading this commitlog I
>>>> fail to see the impact for an application.
>>>> Can you share some light?
>>>>
>>>
>>> As far as I can tell there is no impact on any applications.  The old
>>> code, which walked through the list in a forward direction, worked
>>> perfectly well with testpmd and DPDK pktgen applications on Power systems.
>>>
>>> With the ifdef fixed, the core walks the list in the reverse direction
>>> as intended, the code still worked (i.e. no errors or problems were
>>> observed in the same test applications).
>>>
>>> I'm not completely familiar with why memseg lists must be traversed in
>>> the reverse direction for Power systems.  It might be something specific
>>> to Power 8 systems which I'm not actually supporting on DPDK, only the
>>> Power 9 systems that I use for for development and testing.
>>>
>> If the code makes no difference anyway, should we just take it out so?
> 
> +1 :-)

I think there's a need for a larger review of Power8 vs. Power9 support. 
  You currently need to specify Power8 as the DPDK build target (e.g. 
ppc_64-power8-linux-gcc) but all of our internal development and testing 
efforts are targeting Power9 systems.  My preference would be to drop 
Power8 support all together but I'm reluctant to make such a potentially 
large change so close to an LTS release target, and not without 
soliciting some community comment on the idea.  As a result, I'd prefer 
to keep the change "as is" for this release.

Dave