[ofa-general] New proposal for memory management

[Woodruff, Robert J]

Jeff wrote,
>I would be extremely hesitant to have an OpenFabrics-provided library  
>do this.  MPI implementations spend a *lot* of time an effort on this  
>section of code because it is *the* heart of the MPI message passing  
>engine.  To be blunt: here is not enough MPI expertise in the current  
>set of OpenFabrics developers to build such a library.  I doubt that  
>the academic and proprietary MPI implementations would want to  
>contribute resources to make one, either (it's their secret sauce!).

Interesting that you would want the OFA developers to implement a 
memory registration cache and think they could manage the registration
of MPI memory better than MPI can, but then say that tag-matching drivers
in MPI are their secret sauce. Seems like registration caching is also
some of various MPI's secret sauce. 

>Indeed, to make such a proposal work, there would, by definition, have  
>to be new hardware capabilities, and therefore new verbs to support  
>those hardware capabilities.  So this might just end up as new verbs  
>anyway -- not a new middleware library.

Yes, new hardware capabilities would be needed for this and it is always
hard to get new hardware features added, but if they were added to some
future IBTA or iWarp spec, I think it would be good for MPIs, as we have
seen that this is the way other interconnects like myrinet can achieve good
performance for MPI applications.

Anyway, just thought I would bring it up as a possibility for solving 
some of the issues that you raised at Sonoma.

woody