SimHost: A Lightweight End-to-End Simulation Framework for HPC Network Systems

As high-performance computing (HPC) systems continue to grow in scale and complexity, simulation has emerged as a crucial tool for evaluating network performance, especially when real hardware is unavailable. However, achieving highly accurate results quickly and with low overhead in large-scale network evaluations remains a significant challenge. To tackle this issue, we propose SimHost, a lightweight end-to-end offline simulation framework featuring flexible communication and host models tailored for large-scale network simulations. SimHost enables the replay of application communication events without requiring an actual or virtualized execution environment or hardware. It accurately restores the message passing and system processing overheads of real application execution, delivering evaluation results consistent with physical deployments. With its cross-platform and discrete event design, SimHost integrates seamlessly with existing simulators, needing only minimal modifications for synchronous operation. Evaluations and use cases confirm that SimHost’s workloads accurately replicate real-world scenarios. Experimental results indicate that SimHost achieves less than 5.12% error in application completion time compared to the testbed, while maintaining only 7% simulation runtime overhead when scaled to 2048 nodes relative to synthetic workloads.