The Road to Parallelism Leads Through Sequential Programming

Multicore processors are already ubiquitous and are now the targets of hundreds of thousands of applications. Due to a variety of reasons parallel programming has not been widely adopted to program even current homogeneous, known-resource multicore processors. Future multicore processors will be heterogeneous, be increasingly less reliable, and operate in environments with dynamically changing operating conditions. With energy efficiency as a primary goal, they will present even more parallel execution challenges to the masses of unsophisticated programmers. Rather than attempt to make parallel programming more practical by chipping away at the multitude of its known drawbacks, we argue that sequential programs and their dynamic parallel execution is a better model. The paper outlines how to achieve: (i) dynamic parallel execution from a suitably-written statically sequential program, (ii) energy-efficient execution by dynamically and continuously controlling the parallelism, and (iii) a low-overhead precise-restartable parallel execution.