Vivek Kumar
Australian National University

Designing a Faster Try-Catch model Work-Stealing

Work-stealing is a promising approach for effectively exploiting software
parallelism on parallel hardware. A programmer who uses work-stealing
explicitly identifies potential parallelism and the runtime then schedules
work, keeping otherwise idle hardware busy while relieving overloaded hardware
of its burden. However, work-stealing comes with substantial overheads. Our
prior work demonstrates that using the exception handling mechanism of modern
VMs and gathering the runtime information directly from the victim’s execution
stack can significantly reduce these overheads.

In this paper we identify the overhead associated with managing the work-
stealing related information on a victim’s execution stack. A return barrier
is a mechanism for intercepting the popping of a stack frame, and thus is a
powerful tool for optimizing mechanisms that involve scanning of stack state.
We present the design and preliminary find- ings of using return barriers on a
victim’s execution stack to reduce these overheads. We evaluate our design
using classical work-stealing benchmarks. On these benchmarks, compared to our
prior design, we are able to reduce the overheads by as much as 58%. These
preliminary findings give further hope to an already promising technique of
harnessing rich features of a modern VM inside a work-stealing scheduler.