How can Garbage Collection be energy efficient by dynamic offloading?

Garbage Collection (GC) is still a major issue in JVM for both mobile and cluster computing. GC offloading is proposed to improve the performance of GC by delivering part or all of the operations into another dedicated GC hardware. However, the traditional offloading just offloads directly not considering the phase change of GC behavior, which can be classified into two different groups: minor GC and major GC. The minor GC is fast and frequently invoked, while major GC is expensive in terms of time but seldom takes place. The direct offloading made GC workload frequently hopping between main processor and GC hardware, introduced a noticeable overhead and offset any possible benefits of workload loading. To solve this issue, we propose to offload GC dynamically by a careful selection of profitable and harmful GC operations. We also made a case study on Apache Spark, a lightning-fast cluster computing platform. It shows dynamic offloading can yield nearly 42.6% performance improvement with a concurrent 32.1% in energy cost reduction.