[fedora-arm] OpenMPI atomics patch

[Jon Masters]

On 11/13/2012 02:27 PM, Leif Lindholm wrote:

> First of all, thanks for doing this.

No problem! Thanks for doing a bunch of the other OpenMPI bits :)

> Now on to some picky feedback:
> 
> - The only current difference between the ARMV6 and the ARMV7 versions is the use of cp15
> 
>   or DMB in the standalone barrier functions. Could this not be done through some sort of
> 
>   macro instead?

That could be done. I had been planning to throw this over the wall at
the OMPI guys and say "hey, how do you actually want to fix this?"

> - If we're playing around in here, might as well add support for (32-bit) ARMv8?

Oh, 32-bit. Hmmm. I guess. I assume you mean A32, in which case we can
just reuse the ARMv7 code with a couple of extra lines?

> - Can you not set ompi_cv_asm__arch to the target file name rather than copying around?

Nope :) That's what I did at first (pretty much your stuff below).
Unfortunately, the OpenMPI codebase is a total mess. I also didn't want
to do assembly calls to kernel helpers, but it was easier to do that
than to figure out what the heck they are doing. However. If you want to
have another poke at that option (don't forget to search for all their
uses of the ompi_vc_asm arch) then I think that's awesome :)

Jon.