Top500: Frontier Is Still On Top

The latest versions of the Top500 and Green500 lists were just released on May 22, 2023. The last time that I wrote about the Green500, a Chinese machine, NRCPC’s Sunway TaihuLight, was sitting at the top of the Top500 list. It’s been a while since I last wrote about these lists and it’s interesting to look back at the leap in performance and energy efficiency over the past 7 years.

Fig. 1: Energy efficiency vs. system performance.

Frontier was the first, and remains the only, true Exaflop machine and continues to improve on its performance with an HPL score jumping from 1.02 Eflop/s in November 2022 to a new world’s best 1.194 Eflop/s today. Frontier is based on the HPE Cray EX235a architecture powered by 3rd Gen AMD EPYC 64C 2GHz CPUs optimized for HPC and AI, with AMD Instinct 250X accelerators. It has a total of 8,699,904 cores that produces an energy efficiency rating of 52.59 GFLOPS/W. As was previously pointed out in the 2016 article, the Grand Challenge goal was 1 ExaFLOPS/20MW (equivalent to 50 GFLOPS/W) and Frontier has pushed through that milestone.

Figure 1 shows the top 100 Green500 machines from June 2016 and May 2023. The upper rightmost points for each correspond to Sunway TaihuLight (red) and Frontier (blue) respectively. There’s also a clear up and to the right shift overall in the 100 points for each. It took approximately 6 years to gain an order of magnitude in performance and if it were possible to keep that pace that would imply then that it would be roughly another 17 years (or around 2040) before we would see a Zettascale computing system.

The system at the top of the Green500 is named Henri from the Flatiron Institute and is a ThinkSystem SR670 V2, Intel Xeon Platinum 8362 32C 2.8GHz, NVIDIA H100 80GB PCIe, Infiniband HDR platform. It ranks 255^th on the Top500 in terms of performance and has a leading energy efficiency of ~65.4 GFLOPS/W. The next 6 systems on the list are all based on HPE Cray EX235a. Rounding out the top 10 are two more systems based on Intel Xeon Platinum CPUs paired with NVIDIA accelerators in 8^th and 10^th and an AMD EPYC paired with AMD Instinct accelerators in 9^th. Frontier at Oak Ridge National Lab and LUMI at EuroHPC/CSC rank 6^th and 7^th in terms of energy efficiency and 1^st and 3^rd on the Top500. These two systems were the only two to score in the top 10 on both lists, with the number 3 Green500 system, Adastra at Grand Equipement National de Calcul Intensif – Centre Informatique National de l’Enseignement Suprieur (GENCI-CINES), just missing out and appearing 12^th in the Top500.

As can be seen in figure 1, Sunway TaihuLight, while it has fallen back in terms of its once leading energy-efficiency to 80^th on the Green500, is still ranked 7^th on the Top500 list. This in part demonstrates the challenges in putting together these extremely large systems that push the high-performance envelope and that future gains in performance are always contingent on finding more energy-efficient ways to build these large systems.