Isambard ARM supercomputer takes shape

Team develops simulator for world's largest ARM supercomputer
13th September 2018

The world’s first 64bit ARM supercomputer is coming life, with early benchmarks showing is is highly competitive with existing Intel-based high performance computing (HPC) systems.

The £4.7m three year Isambard project uses 10,752 Armv8 cores (168 x 2 x 32) in 32core, 2.1GHz ThunderX chips from Cavium. The machine is built in the Cray XC50 Scout form factor with high-speed Aries interconnect and an optimised software stack from Cray, which has its European research centre in Bristol.

“The results show ThunderX2 performance is competitive with current high-end server CPUs, while performance per dollar is compelling,” said Simon McIntosh-Smith, Professor of High Performance Computing at the University of Bristol (above). “The full Isambard XC50 Arm system is coming up now, and we are aiming to have early results to share later this year.”

The first phase was installed in March 2017 and the current phase, the ARM chips, is being brought up at the moment. Benchmarking of the new system has shown that the performance is comparable to supercomputers using Intel’s Xeon chips but at a third of the cost and power consumption.

“The signs are that Arm-based systems are now real alternatives for HPC, reintroducing much needed competition to the market,” he said.

The team at Bristol has also developed a new configurable cycle accurate simulator that comes within 5 to 10% of the performance of the TX2 hardware. This is highly configurable to almost any design of HPC processor architecture, and the team is working on a version of the latest high performance ARM chip from Fujitsu called the A64fx. There are also plans for future support for x86 and RISC-V (MIPS) co-processors.

Isambard is being developed as part of a project by the GW4 collaboration of the universities of Bristol, Bath, Exeter and Cardiff