Magellan Final Report - Office of Science - U.S. Department of Energy

Magellan Final Report
Figure 9.11: MILC benchmark results on OpenStack run on 32 nodes (1 and 8 cores per node).
9.2.3 DNS
DNS3D, a computational fluid dynamics application, was chosen as our second real-world MPI application
for testing purposes. It was considered both because of its nature as a primarily network-bound application
and its widespread use among many scientific disciplines.
Ten trials were run using 4-cores-per-node, 8-node clusters on both virtual machines and raw hardware.
The average time-to-solution for the virtual and raw hardware clusters was 2.721 and 0.214 seconds respectively,
giving a factor of ten performance penalty for running in a virtual environment. Like the previous
test, this is again most likely a result of high network latency and contention for network bandwidth.
9.2.4 Phloem
For a general set of MPI benchmarks, the Phloem toolkit was chosen [68]. This suite of applications was
designed for diagnosis of performance problems in an MPI cluster, and it was run with the expectation
of determining which aspects of virtual networking in particular are detrimental to the performance of
parallel applications. The first application shown is SQMR, a general MPI point-to-point message bandwidth
benchmark, run on a 16-rank 2-node cluster. The results shown below are averages of ten 1000-round runs.
Figure 9.12: Phloem SQMR point-to-point average throughput (10K rounds).
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