CFD applications benefit from features such as high memory bandwidth, low-latency / high-bandwidth network interconnect, and access to a fast-parallel file system in order to efficiently scale the simulations to a large number of instances. As such, a mix of Elastic Fabric Adapter (EFA) enabled instances have been used for running benchmarks for this blog.
Amazon recently announced the Amazon EC2 Hpc6a instance type which delivers 100 Gbps networking through EFA with 96 cores of third-generation AMD EPYC™ (Milan) and 384 GB RAM. Along with Hpc6a, we have used the Intel Xeon Scalable processor (Ice Lake) based, Amazon EC2 C6i instance type, and the Intel Xeon (Skylake) based Amazon EC2 C5n instances for running these benchmarks. All three instance types offer EFA support with up to 100 Gbps networking. These instances are powered by the AWS Nitro System, an advanced hypervisor technology delivering the required compute and memory resources for increased performance and security.
To understand how Simcenter STAR-CCM+ performs on various Amazon EC2 instance types, we plotted how simulation performance varies versus number of cores for each of the two test cases in Figure 2 (a, b). The Le Mans case with 17 million cells is scaled to 3000 cores, and the high-lift aircraft case with 147 million cells is scaled to 9600 cores. Simulation performance is represented in terms of iterations per minute that are averaged over the last 100 iterations of the simulation.
For the Le Mans case, C6i offers about 17% improvement over C5n and Hpc6a instances, at 3200 cores. For the high-lift aircraft case, C6i offers about 18% to 30% improvement over C5n and Hpc6a instances, at 6400 cores.
Application performance is an important indicator of project turnaround times and ultimately, the final time to market. However, customers also want to understand and cut project costs, especially when running large simulations.
From the benchmarks, we see that, depending on the case size and core count, C6i offers about 30% – 60% cost savings compared to C5n instances. On the other hand, Hpc6a consistently offers about 65% – 70% cost savings compared to C5n instances.
This post describes the price and performance summary of running CFD simulations using Simcenter STAR-CCM+ software on AWS. Amazon EC2 Hpc6a offers the lowest cost, with about 65% cost savings over C5n, and about 40% cost savings over C6i, depending on the test case. Watch out in the future for further posts on the recently-released GPU-enabled version of Simcenter STAR-CCM+, where we’ll also compare GPU versus CPU results on AWS.