Re-evaluating Network Onload vs. Offload for the Many-Core Era

This paper explores the trade-offs between on-loaded versus offloaded network stack processing for systems with varying CPU frequencies. This study explores the differences of onload and offload using experiments run at different DVFS settings to change the frequency, while measuring performance and power. This allows for a quantitative comparison of the the performance and power and trade-offs between onload and offload cards, with a wide range of CPU performances. The results show that there is often a significant performance increase in using offloaded cards especially at lower CPU frequencies, with only a small increase in power usage. This study also uses MPI profiling to analyze why some applications see a larger benefit than others. This paper's contributions are an analytical, quantitative analysis of the trade-offs between onload and offload. While there has been debate to this question, this is the first, to the authors' knowledge, analytical evaluation of the performance difference. The range of frequencies analyzed give insight on how this MPI might perform on different architectures, such as the low frequency, many-core CPUs. Finally, the power measurements allow for the study to provide further depth in the analysis.