A few weeks ago we posted a shorty linking to an HPL performance estimator from Dell that would, among other things, estimate your Top500 rank based on a few parameters about the machine.
I got an email recently from Mohamad Sindi at the EXPEC Computer Center (part of Saudi Aramco, the state-owned national oil company of Saudi Arabia). Mohamad pointed me to a calculator they developed that provides a little more information.
The tools take similar data, although the Aramco tool requires the memory per node while Dell’s does not. Aramco’s tool also includes the ability to estimate where you would appear on current and future lists (nifty), and provides suggestions on running the HPL for your particular configuration to get the best performance (helpful if accurate). From Mohamad’s email:
As for actually running the HPL benchmark on a cluster‐based supercomputer, the tool aids in doing so by suggesting some of the critical parameters needed for the benchmark. Tuned values of the HPL grid size and the problem size “N” are calculated and suggested by the tool to ease the process of running HPL. All of this is accompanied by a detailed step by step procedure of how to successfully run HPL on the cluster. Saudi Aramco hopes that this tool will aid the HPC community in benchmarking and ranking HPC supercomputers. The “Top500 HPL Calculator” tool has been hosted on SourceForge.org since August 2009.
While I cannot vouch for the execution tips, I did compare the ranking predictions for the two tools for Jade, an XT4 system installed in the US currently ranked at #93 and 56.25 TFLOPS (Rmax). I had to use ranking predictions based on the 11/2009 list since the Dell tool is a little out of date.
The Aramco tool predicted a ranking of 80 on that list (60.568 TFLOPS Rmax), while the Dell tool predicted 79 (60.568 TFLOPS Rmax). In both cases I assumed 84% efficiency (the default on the Dell tool is 82%). The actually ranking of Jade in November was #83.
So, there you have it.