[mpich-discuss] [PATCH v2] test: add attrdeleteget, MPI_Attr_get called from delete_fn

[Fab Tillier]

Pavan Balaji wrote on Mon, 20 May 2013 at 06:57:42

>> And what about the non-deterministic effects that I called out in the
>> email back in 2011 -- are those allowed, and if so, do we need to say
>> that they're non-deterministic?  ...and so on.-
> 
> Right, we did talk about the non-determinism on this email thread before
> you joined in, but we concluded that there's only one sensible way.  Of
> course, that should be clarified in the standard.  But it's not a major
> change in implementations, I think.

One thing we didn't discuss yet is whether the callbacks are called during MPI_Finalize, for attributes assigned to built-in communicators and/or types, and what operations are allowed therein.  This makes it that much more interesting to do non-blocking I/O from the callback, since technically the application has called MPI_Finalize.  However, if we go with the "as if MPI_*_DELETE_ATTR was called before the call, then anything should be valid, and we should have an advice to users regarding Finalize.

Boy, did this got messy quickly...

-Fab