Energy Consumption Improvement of Shared-Cache Multicore Clusters Based on Explicit Simultaneous Multithreading

The use of multicore clusters is one of the strategies used to achieve energy-efficient multicore architecture designs. Even though chips have multiple cores in these designs, cache constraints such as size, latency, concurrency, and scalability still apply. Multicore clusters must therefore implement alternative solutions to the shared cache access problem. Bigger or more frequently accessed caches consume more energy, which is a problem in explicit multithread concurrency. In this work, we simulate different multicore cluster architectures to identify the best configuration in terms of energy efficiency, concerning a varying number of cores, cache sizes and sharing strategies. We also observe the simultaneous and individual multithreading concurrency of two application groups. The results showed that for applications with regular tasks loads, the simultaneous multithreading approach was 43.6% better than the individual one, in terms of energy consumption. For irregular tasks loads, individual executions proved to be the best option, with an increase of up to 81.3% in energy efficiency. We also concluded that shared L2 caches were up to 13.4% more energy-efficient than private cache configurations.