Robinhood: Towards Efficient Work-Stealing in Virtualized Environments

Work-stealing, as a common user-level task scheduler for managing and scheduling tasks of multithreaded applications, suffers from inefficiency in virtualized environments, because the steal attempts of thief threads may waste CPU cycles that could be otherwise used by busy threads. This paper contributes a novel scheduling framework named Robinhood. The basic idea of Robinhood is to use the time slices of thieves to accelerate busy threads with no available tasks (referred to as poor workers) at both the guest Operating System (OS) level and Virtual Machine Monitor (VMM) level. In this way, Robinhood can reduce the cost of steal attempts and accelerate the threads doing useful work, so as to put the CPU cycles to better use. We implement Robinhood based on BWS, Linux and Xen. Our evaluation with various benchmarks demonstrates that Robinhood paves a way to efficiently run work-stealing applications in virtualized environments. Compared to Cilk++ and BWS, Robinhood can reduce up to 90 and 72 percent execution time of work-stealing applications, respectively.