Fujitsu A64FX

The A64FX is a 64-bit ARM architecture microprocessor designed by Fujitsu.[1][4] The processor is replacing the SPARC64 V as Fujitsu's processor for supercomputer applications.[5] It powers the Fugaku supercomputer, the fastest supercomputer in the world by TOP500 rankings as of June 2020.[4][5][6][7]

A64FX

General information
Launched	2019
Marketed by	Fujitsu
Designed by	Fujitsu
Common manufacturer(s)	TSMC
Architecture and classification
Min. feature size	7 nm
Microarchitecture	In-house
Instruction set	ARMv8.2-A with SVE and SBBA level 3
Physical specifications
Cores	48 per CPU[1] plus optional assistant cores[2][3]

Design

Fujitsu collaborated with ARM to develop the processor; it is the first processor to use the ARMv8.2-A Scalable Vector Extension SIMD instruction set with 512-bit vector implementation.[4] A prototype computer using the processors was ranked as the 159th fastest computer in the world on the TOP500 list in November 2019.[8]

It has "Four-operand FMA with Prefix Instruction",[1] i.e. MOVPRFX instruction followed by FMA3 (ARM, like RISC in general, is a 3-operand machine, doesn't have space for 4 operands), which get packed into a single operation in the pipeline. For the processor the designer claim ">90% execution efficiency in (D|S|H)GEMM and INT16/8 dot product".[1]

The processor uses 32 gigabytes of HBM2 memory with a bandwidth of 1 TB per second.[4] The processor contains 16 PCI Express generation 3 lanes[1] to connect to accelerators (hypothetical e.g. GPUs and FPGAs). The reported transistor count is about 8.8 billion.[4]

Each A64FX processor has 4 NUMA nodes, with each NUMA node having 12 compute cores, for a total of 48 cores per processor.[9][2][3] Each NUMA node also has its own level 2 cache, HBM2 memory, and assistant cores for non-computational purposes.[9]

Fujitsu intends to produce lower specification machines with reduced assistant cores.[2][3] Reliability, availability and serviceability (RAS) capabilities are claimed, i.e. ~128,400 error checkers in total.

Implementations

Fujitsu designed the A64FX for the Fugaku. As of June 2020, the Fugaku is the fastest supercomputer in the world by TOP500 rankings.[10] Fujitsu intends to sell smaller machines with A64FX processors.[2][3] Anandtech reported in June 2020 that the cost of a PRIMEHPC FX700 server, with 2 A64FX nodes, was ¥4,155,330 (c. US$39,000).[11]

Cray is developing supercomputers using the A64FX.[12][13] The Isambard 2 supercomputer is being built for a consortium in the United Kingdom, led by the University of Bristol and also including the Met Office, using the Fujitsu processors.[14][15] It is an upgrade to the Isambard supercomputer which was built with the Marvell ThunderX2, another ARM architecture microprocessor.[15]

See also

• Comparison of ARMv8-A cores
• SPARC64 V
• ThunderX2 – another ARM architecture high performance computing microprocessor
• Huawei Kunpeng 920 – also an ARM high-performance microprocessor, but developed by the Huawei-owned HiSilicon. Only available in China.

References

1. "Hot Chips 30 conference; Fujitsu briefing" (PDF). Toshio Yoshida.
2. "Fujitsu Launches New PRIMEHPC Supercomputers Using Fugaku Technology - Fujitsu Global". www.fujitsu.com. 13 November 2019. Retrieved 28 June 2020.
3. "FUJITSU Supercomputer PRIMEHPC Specifications". www.fujitsu.com. Retrieved 28 June 2020.
4. "Fujitsu Successfully Triples the Power Output of Gallium-Nitride Transistors - Fujitsu Global". www.fujitsu.com. Fujitsu. Retrieved 8 March 2020.
5. Morgan, Timothy Prickett (24 August 2018). "Fujitsu's A64FX Arm Chip Waves The HPC Banner High". The Next Platform. Retrieved 8 March 2020.>
6. "Outline of the Development of the Supercomputer Fugaku | RIKEN Center for Computational Science RIKEN Website". www.r-ccs.riken.jp. Retrieved 18 November 2020.
7. "Supercomputer Fugaku - Supercomputer Fugaku, A64FX 48C 2.2GHz, Tofu interconnect D | TOP500". www.top500.org. Retrieved 18 November 2020.
8. "A64FX prototype - Fujitsu A64FX, Fujitsu A64FX 48C 2GHz, Tofu interconnect D | TOP500 Supercomputer Sites". www.top500.org. Retrieved 8 March 2020.
9. Odajima, Tetsuya; Kodama, Yuetsu; Tsuji, Miwako; Matsuda, Motohiko; Maruyama, Yutaka; Sato, Mitsuhisa (September 2020). "Preliminary Performance Evaluation of the Fujitsu A64FX Using HPC Applications". 2020 IEEE International Conference on Cluster Computing (CLUSTER): 523–530. doi:10.1109/CLUSTER49012.2020.00075. |access-date= requires |url= (help)
10. "Supercomputer Fugaku - Supercomputer Fugaku, A64FX 48C 2.2GHz, Tofu interconnect D | TOP500". www.top500.org. Retrieved 18 November 2020.
11. Cutress, Dr Ian (26 June 2020). "HPC Systems Special Offer: Two A64FX Nodes in a 2U for $40k". www.anandtech.com. Retrieved 28 June 2020.
12. "Cray, Fujitsu Both Bringing Fujitsu A64FX-based Supercomputers to Market in 2020". HPCwire. 13 November 2019. Retrieved 8 March 2020.
13. Tsukimori, Osamu (7 January 2021). "Japan's Fugaku supercomputer is tackling some of the world's biggest problems". The Japan Times. Retrieved 26 January 2021.
14. Bristol, University of. "February: GW4 Isambard - News and features - University of Bristol". www.bristol.ac.uk. Retrieved 8 March 2020.
15. Burt, Jeffrey (9 March 2020). "Isambard 2 Is About Driving Technology Diversity". The Next Platform. Retrieved 9 March 2020.