BindMe: a thread binding library with advanced mapping algorithms

Abstract

Binding parallel tasks to cores according to a placement policy is one of the key aspects to achieve good performance in multicore machines because it can reduce on-chip communication among parallel threads. Binding also prevents operating system from migrating threads, which improves data locality. However, there is no single mapping policy that works best among all different kinds of applications and platforms because each machine has a different topology and each application exhibits different communication pattern. Determining the best policy for a given application and machine requires extra programming effort. To relieve the programmer from that burden, we introduce BindMe, A thread binding library that assists programmer to bind threads to underlying hardware. BindMe incorporates state-of-the-art mapping algorithms, which use communication pattern in an application to formulate an efficient task placement policy. We also introduce ChoiceMap, A communication aware mapping algorithm that respects mutual priorities of parallel tasks and performs a fair mapping by reducing communication volume among cores. We have tested BindMe and ChoiceMap with various applications from NaS parallel benchmark and Rodinia bechmark. Our results show that choosing a mapping policy that best suits the application behavior can increase its performance and no single policy gives the best performance across different applications.