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World's fastest: IBM's Roadrunner supercomputer breaks petaflop barrier using Cell and Opteron processors



Roadrunner is a supercomputer built by IBM at the Los Alamos National Laboratory in New Mexico, USA. Currently the world's fastest computer, the US$133-million Roadrunner is designed for a peak performance of 1.7 petaflops, achieving 1.026 on May 25, 2008.

Roadrunner differs from many contemporary supercomputers in that it is a hybrid system, using two different processor architectures. Usually supercomputers only use one, since such a design is easier to design and program for. To realise the full potential of Roadrunner, all software will have to be written specially for this hybrid architecture. The hybrid design consists of dual-core Opteron server processors manufactured by AMD using the standard AMD64 architecture. Attached to each Opteron core is a Cell processor manufactured by IBM using Power Architecture technology. As a supercomputer, the Roadrunner is considered an Opteron cluster with Cell accelerators, as each node consists of a Cell attached to an Opteron core and the Opterons to each other.

Processors

Roadrunner is unique for its hybrid design using two different models of processors.


Opteron

AMD Opteron 2210, running at 1.8 GHz. These are processors with two general purpose cores each. Opterons are used both in the computational nodes feeding the Cells with useful data and in the system operations and communication nodes passing data between computing nodes and helping the operators running the system. Roadrunner has a total of 6912 Opteron processors (6480 computation, 432 operation), for a total of (12960+864) 13824 cores.


PowerXCell

IBM PowerXCell 8i, running at 3.2 GHz. These processors have one general purpose core (PPE), and eight special performance cores (SPE) for floating point operations. Roadrunner has a total of 12,960 PowerXCell processors, with 12,960 PPE cores and 103,680 SPE cores, for a total of 116,640 cores.

Overall system information:
6,480 Opteron processors with 51.8 TiB RAM (in 3,240 LS21 blades)
12,960 Cell processors with 51.8 TiB RAM (in 6,480 QS22 blades)
216 System x3755 I/O nodes
26 288-port ISR2012 Infiniband 4x DDR switches
296 racks
2.35 MW power .