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Fujitsu Raises Arm Over SPARC

September 25, 2018

Author: Tom R. Halfhill

SPARC isn’t quite extinguished, but it’s dimming. Although Fujitsu’s product roadmap still shows a 7nm SPARC design in progress, the company’s next-generation supercomputer switches to a custom 64-bit Arm processor built in the same technology. This powerful 52-core chip will appear in the mammoth Post-K supercomputer scheduled to debut in 2021. “Post-K” is a placeholder name for the machine that will supersede Fujitsu’s famous K supercomputer, which in 2011 became the world’s first to exceed 10 petaflop/s. The company has initial silicon samples of the chip and demonstrated a single-rack Post-K prototype at a supercomputer conference earlier this year, but building the full system will take years.

At last month’s Hot Chips conference, Fujitsu said the new Arm-based A64FX processor delivers at least 2.7 double-precision teraflop/s of peak performance per chip, so it’s about 21x faster than the Sparc64 VIIIfx chips in the K supercomputer. The company estimates Post-K will be about 100x faster than its predecessor, which contains 88,128 processors. Thus, Post-K could become the first exascale computer—a system capable of delivering at least one exaflop/s (one billion billion floating-point operations per second). Both machines are joint projects with the Riken Advanced Institute for Computational Science in Kobe, Japan. Currently, the world’s fastest supercomputer is the 188-petaflop/s Summit system at Oak Ridge National Laboratory in Tennessee; it employs IBM Power9 processors and Nvidia Tesla V100 GPUs.

Fujitsu is switching to Arm to increase power efficiency and to tap the growing ecosystem of Arm software and development tools. Power efficiency is the main motivation, however; Arm is new to supercomputing, so its big-iron software library is sparse. Fujitsu is withholding the chip’s clock frequency (we estimate 1.8GHz) and power consumption (we estimate 150W) but says Post-K will gobble 30–40 megawatts. That’s 2–3x more than both its predecessor and the Summit machine.

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