Profiling-Assisted Prefetching with Just-In-Time Compilation

The Decoupled Access/Execute(DAE) approach is a method to reduce the energy consumption of task-based programs, based on dividing tasks in two phases where the first phase prefetches data at a low CPU frequency and the following phase performs computation at a high CPU frequency. The goal of this project is to extend this approach to sequential programs and examine the benefits of optimising the access phase to better suit the architecture the program runs on, and the program input. By using a Just-In-Time compiler to dynamically optimise the program and by utilising profiling tools to obtain runtime information, we have examined the possible benefits of the DAE approach on sequential programs with optimised access phases. We compared the benefits with the cost of dynamic optimisation by testing the method on selected benchmarks from the SPEC CPU 2006 suite. The results indicate that for many types of sequential programs dynamically optimised DAE is suitable but care must be taken when determining how to optimise the access phases