Fine-Grain MPI

Fine-Grain MPI (FG-MPI) extends the execution model of Message Passing Interface (MPI) to allow for interleaved execution of multiple concurrent MPI processes inside an OS-process. FG-MPI is integrated into the MPICH middleware and has a light-weight design based on coroutines that can scale to millions of MPI processes on a node or across nodes on a cluster. FG-MPI provides the ability to take advantage of finer-grain parallelism available on today's multicore systems, while maintaining MPI's rich support for communication inside clusters.

FG-MPI adds a new dimension to mapping processes onto nodes. Its flexible process mapping allows granularity of MPI programs to be adjusted through the command-line to better fit the cache leading to improved performance. For communication efficiency, we exploit the locality of MPI processes in the system and implement optimized communication between concurrent processes in the same OS-process. We have investigated scalability issues related to MPI groups and communicators and defined new efficient algorithms for communicator creation and storage of process maps.

FG-MPI's light-weight design and ability to expose massive concurrency enables a task-oriented programming approach that can be used to simplify MPI programming and avoid some of the non-blocking communication. The fine-grain nature of FG-MPI makes it suitable for chips with a large number of cores. As well, it is based on message-passing and it will be portable to multicore chips with or without support for cache-coherence.

FG-MPI supports function-level concurrency which enables design of novel algorithms and techniques to achieve scalable performance and match the number of processes to the problem rather than the hardware.

FG-MPI at a glance: FG-MPI Flyer

 

We acknowledge the support of the on-going FG-MPI project by: