These are great points. As a result, I went and read the following: https://www.hpcg-benchmark.org/custom/index.html%3Flid=158&slid=281.html which suggests that HPL and HPCG may be viewed as optimistic-pessimistic “bookends” on machine performance. More interestingly perhaps, for real-world (non-benchmark) multigrid conjugate-gradient iterative solution approaches (eg. for FD or FEM), one may be able to apply “latency hiding” strategies that up the actual performance (graph coloring oriented? GraphBLAS?). HPCG apparently deliberately avoids those in order to more fully depress HPC enthusiasts the world over, by one full log cycle (eh-he-eh!)!

Dominates the new machines on the list. No more, no less.

I’m looking forward to the face-off between the grown-up JEDI (which should blossom into a thunderous greco-roman wild-card $DEITY) and the all-dressed, and tuned-up, El Capitan. Their computational efficiencies should somewhat converge by the next Top500, down from 88% for JEDI (to something more similar to Alps’ 76%, as more modules are combined), and up from 61% for El Capitan (to something above Frontier’s 70%, owing to a more tightly integrated arch, and tuning). Seeing how this will be a contest between jedi grasshoppers and epyc zen instincts, one can only expect the related computational kung-fu to be truly mind-blowing!

Supercomputers have always been so much better at the easy stuff than the hard stuff, and the easy stuff isn’t really very interesting. This has been true even back in the Cray Vector days when the ratio of bandwidth to compute was a thousand times better.
The good news, is that these things ARE getting better at the hard stuff, just not nearly as fast as the HLP flop number would have you believe. HBM really is a useful improvement over ddr ram. hundred gigabit networks really are better than gigabit networks, even on the hard problems. It’s just that hard problems have performance of teraflops, not exaflops, even on the best machines. But better than the megaflops they used to get.

Not sure. But good points, and good questions. I find the HPCG test terrifying because it shows just how crappy these things really are at the hard stuff.

The way I see it, HPL represents a stress test to verify the floating point, networking and power supplies are fit for purpose while HPCG is a better reflection of scientific workloads. With that in mind, HPL per watt as in the Green500 is interesting but science per watt is better reflected by HPCG per watt.

Since computers draw different amounts of power depending on whether they’re running HPL or HPCG, is there a way to infer HPCG per watt from the published data?