Software developed by Indiana University and partner institutions helped the Fukitsu K Computer be named reigning champion of the world's fastest supercomputers.

At the International Supercomputing Conference, June 2011, a new Top 500 list of supercomputers (http://top500.org) was unveiled. Based on the new ranking, the K Computer, a Japanese supercomputer which performs more than 8 quadrillion calculations per second (8 petaflops per second), is the world's highest performing supercomputer.

A key factor in reaching these unprecedented speeds was the use of Open MPI (Message Passing Interface), an open-source software package initially co-developed by IU's Open Systems Lab (OSL) and three partner institutions. OSL is part of Pervasive Technology Institute at Indiana University.

"To make a parallel computation run at a high speed, different processors need to be able to communicate data as quickly as possible," said OSL Director Andrew Lumsdaine. "Hardware processing has become ever faster, but Open MPI is critical to enabling supercomputers to use that processing power."

The Message Passing Interface (MPI) is a specification that allows processes to communicate with one another. The MPI library used in the K Computer is based on the Open MPI 1.4 series with some extensions. The OSL has played a key role since the Open MPI project launched in 2004.

Jeff Squyres, a former researcher at IU and one of the Open MPI founders said, "Open MPI, an efficient MPI implementation, played a big part in achieving the stellar performance by powering the 8 petaflop runs at an amazing 93% efficiency." Squyres is currently a core developer of Open MPI at Cisco.

The Open MPI software has also shown incredible extensibility. "The K Computer has shown that Open MPI is scalable to the level of 68,000 processes, by connecting 68,544 nodes via our custom interconnect. We are pleased to use such great open source software," said Takahiro Kawashima, an MPI library development team member at Fujitsu.