[sanxiyn]

While Sunway TaihuLight has weak HPCG performance, 0.3% number should be understood in context. Tianhe-2 (#2 system) scores 1.1%, and Titan (#3, US #1 system) scores 1.2% for HPCG. So Sunway TaihuLight is 3~4x worse for HPCG compared to other top systems.

Note that K computer (#5 system, Japan) scores 4.9% for HPCG. So Tianhe-2 and Titan are again 4x worse for HPCG compared to systems which score best for HPCG.

[bhouston]

Why does the Sunway TaihuLight have bad HPCG performance? I suspect it has to do with memory bandwidth needed to serve 260C on the same chip?

[sanxiyn]

Yes, it's memory and interconnect.

I don't think it's as simple as LINPACK bad, HPCG good. LINPACK is representative for some workloads, when compute dominates. HPCG aims to balance compute and memory. There is Graph500, if memory dominates for your workload.

By the way, K computer is #1 in Graph500.

[ams6110]

http://www.graph500.org/

The interconnect on the Sunway TaihuLight seems to be standard Infiniband, from reading other articles about the system.