Pressure-Driven Hardware Managed Thread Concurrency for Irregular Applications

Abstract

Given the increasing importance of efficient data intensive computing, we find that modern processor designs are not well suited to the irregular memory access patterns found in these algorithms. This research focuses on mapping the compiler's instruction cost scheduling logic to hardware managed concurrency controls in order to minimize pipeline stalls. In this manner, the hardware modules managing the low-latency thread concurrency can be directly understood by modern compilers. We introduce a thread context switching method that is managed directly via a set of hardware-based mechanisms that are coupled to the compiler instruction scheduler. As individual instructions from a thread execute, their respective cost is accumulated into a control register. Once the register reaches a pre-determined saturation point, the thread is forced to context switch. We evaluate the performance benefits of our approach using a series of 24 benchmarks that exhibit performance acceleration of up to 14.6X.