On the energy efficiency and performance of irregular application executions on multicore, NUMA and manycore platforms

• Programming for a manycore is challenging.
• Limited memory and NoC are among the most important constraints of manycores.
• For CPU-bound and mixed workloads, MPPA-256 achieves better performance than Xeon.
• MPPA-256 consumes up to 13 × less energy than embedded and general-purpose multicores.

Until the last decade, performance of HPC architectures has been almost exclusively quantified by their processing power. However, energy efficiency is being recently considered as important as raw performance and has become a critical aspect to the development of scalable systems. These strict energy constraints guided the development of a new class of so-called light-weight manycore processors. This study evaluates the computing and energy performance of two well-known irregular NP-hard problems–the Traveling-Salesman Problem (TSP) and K-Means clustering–and a numerical seismic wave propagation simulation kernel–Ondes3D–on multicore, NUMA, and manycore platforms. First, we concentrate on the nontrivial task of adapting these applications to a manycore, specifically the novel MPPA-256 manycore processor. Then, we analyze their performance and energy consumption on those different machines. Our results show that applications able to fully use the resources of a manycore can have better performance and may consume from 3.8 × to 13 × less energy when compared to low-power and general-purpose multicore processors, respectively.