[pooma-dev] Merging native MPI parallelization

[Jeffrey D. Oldham]

Richard Guenther wrote:
> Hi!
> 
> I'd like to merge in a native MPI parallelization.  Unfortunately the
> patch is huge and touches a lot of files.  Basically one part of the patch
> introduces a new #define POOMA_MESSAGING and replaces occourences of
> POOMA_CHEETAH with POOMA_MESSAGING where appropriate.  A lot of tests are
> touched by this and also all the remote engine stuff.  Second, the common
> entry header for messaging support is changed to Tulip/Messaging.h which
> can be unconditionally (or conditionally on POOMA_MESSAGING) included
> instead of Cheetah/Cheetah.h.
> 
> After merging the above changes, the remaining part should only touch
> Tulip/ and the remote engines.  Unfortunately, the serial async scheduler
> is also hacked to support async completion of MPI requests.
> 
> Would it be ok to merge the first part unconditionally in if the second
> part will be accepted?  If it is, I'll try to split the patch
> appropriately.

Native MPI support will be good because it will lower the barrier to 
parallel use.  At the same time, there are probably still Cheetah users 
and we should support them.  Can we do so using POOMA_CHEETAH and 
POOMA_MESSAGING preprocessor definitions?

Packaging the changes to have reasonable size can be difficult.  I think 
all changes should be presented as patches for community review. 
ChangeLog entries will help understand the changes.

-- 
Jeffrey D. Oldham
oldham at codesourcery.com