Accelerating Multi-threaded Application Simulation through Barrier-Interval Time-Parallelism

Abstract

In the last decade, the microprocessor industry has undergone a dramatic change, ushering in the new era of multi-/manycore processors. As new designs incorporate increasing core counts, simulation technology has not matched pace, resulting in simulation times that increasingly dominate the design cycle. Complexities associated with the execution of code and communication between simulated cores has presented new obstacles for the simulation of manycore designs. Hence, many techniques developed to accelerate uniprocessor simulation cannot be easily adapted to accelerate manycore simulation. In this work, a novel time-parallel barrier-interval simulation methodology is presented to rapidly accelerate the simulation of certain classes of multi-threaded workloads. A program delineated into intervals by barriers may be accurately simulated in parallel. This approach avoids challenges originating from unknown thread progressions, since the program location of each executing thread is known. For the workloads tested, wall-clock speedups range from 1.22× to 596×, with an average of 13.94×. Furthermore, this approach allows the estimation of stable performance metrics such as cycle counts with minimal losses in accuracy (2%, on average, for all tested workloads). The proposed technique provides a fast and accurate mechanism to rapidly accelerate particular classes of manycore simulations.