When the MPI Forum reconvened in March 1995, the main reason was to produce a new version of MPI that would have significant new features. The original MPI is being referred to as MPI-1 and the new effort is being called MPI-2. The need and desire to extend MPI-1 arose from several factors. One consideration was that the MPI-1 effort had a constrained scope. This was done to avoid introducing a standard that was seen as too large and burdensome for implementors. It was also done to complete MPI-1 in the Forum-imposed deadline of one year. A second consideration for limiting MPI-1 was the feeling by many Forum members that some proposed areas were still under investigation. As a result, the MPI Forum decided not to propose a standard in these areas for fear of discouraging useful investigations into improved methods.
The MPI Forum is now actively meeting and discussing extensions to MPI-1 that will become MPI-2. The areas that are currently under discussion are: 0.1truein
External Interfaces: This will define interfaces to allow easy extension of MPI with libraries, and facilitate the implementation of packages such as debuggers and profilers. Among the issues considered are mechanisms for defining new nonblocking operations and mechanisms for accessing internal MPI information.
One-Sided Communications: This will extend MPI to allow communication that does not require execution of matching calls at both communicating processes. Examples of such operations are put/get operations that allow a process to access data in another process' memory, messages with interrupts (e.g., active messages), and Read-Modify-Write operations (e.g., fetch and add).
Dynamic Resource Management: This will extend MPI to allow the acquisition of computational resources and the spawning and destruction of processes after MPI_INIT.
Extended Collective: This will extend the collective calls to be non-blocking and apply to inter-communicators.
Bindings: This will produce bindings for Fortran 90 and C++.
Real Time: This will provide some support for real time processing. 0.1truein Since the MPI-2 effort is ongoing, the topics and areas covered are still subject to change.
The MPI Forum set a timetable at its first meeting in March 1995. The goal is release of a preliminary version of certain parts of MPI-2 in December 1995 at Supercomputing '95. This is to include dynamic processes. The goal of this early release is to allow testing of the ideas and to receive extended public comments. The complete version of MPI-2 will be released at Supercomputing '96 for final public comment. The final version of MPI-2 is scheduled for release in the spring of 1997.