Fugaku is a big old supercomputer at RIKEN-RCCS in Kobe, Japan. It is built on Fujitsu A64FX processors with HBM2 and achieved an HPL score of 415.53 PFLOPS on the June 2020 Top500 list.1
System overview
Fugaku has:2
- 158,976 compute nodes
- 158,976 Fujitsu A64FX Arm CPUs
- 432 racks (it’s huge)
396 racks are fully populated with 384 nodes, while 36 racks are half-populated with 192 nodes.2 It’s unclear if those half-racks have half as many shelves or depopulated BoBs.
The Fugaku platform (which doesn’t have a brand name?) has:
- 2x nodes per “CPU Memory Unit” (CMU)
- 8x CMUs per “bunch of blades” (BoB)
- 3x BoBs per shelf
- 8x shelves per rack
Fujitsu sells a platform called PRIMEHPC FX1000 which appears to be identical to Fugaku, but Fujitsu differentiates PRIMEHPC FX1000 and Fugaku branding. Maybe this is the same relationship that Red Storm and Cray XT3 had.
Node architecture
Each node has:2
- 1x Fujitsu A64fx CPU
- 48 Armv8.2-A SVE cores + 2 assistant cores
- 2.0 GHz base, 2.2 GHz max
- 3.072 TF FP64 base, 3.3792 TF FP64 max
- 32 GB HBM2, 1024 GB/s peak bandwidth
- 1x 10-port Tofu D router (28 Gbps x 2 lanes per port)
- 1x PCIe Gen3 x16
Footnotes
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It debuted in at ISC 2020 but got a few more nodes and a higher score by November 2020. ↩