Hi, In MPI22 Standard document [*1*<http://www.mpi-forum.org/docs/mpi-2.2/mpi22-report.pdf>] on page 305 lines 27-30 we can see this paragraph:

The MPI Forum decided not to address resource control because it was not able to

design a portable interface that would be appropriate for the broad spectrum

of existing

and potential resource and process controllers. Resource control can

encompass a wide

range of abilities, including adding and deleting nodes from a virtual

parallel machine, ...

Which means, an MPI-based cluster is not reconfigurable at run time! but in EuroPVM/MPI 2006 a reconfigurable version of MPI for HPC clusters was described by University of New Mexico Scalable Systems Lab [*2*<http://www.pvmmpi06.org/talks/CommProt/venkata.pdf>] and they show that their implementation will enhance performance (the main goal of MPI). So, why in MPI22 standard "*The MPI forum decided not to address resource control*" which can improve both flexibility and performance of an MPI-based cluster? Ref: MPI/CTP: A Reconfigurable MPI for HPC Applications<http://www.springerlink.com/content/w588601267363238/> Regards, Siavash *