X10 at scale

Abstract

X10 is an open-source imperative concurrent object-oriented programming language developed by IBM Research to ease the programming of scalable concurrent and distributed applications. In this talk, I will report and reflect on our experience running HPC application kernels and graph algorithms implemented in X10 on a Petaflop IBM Power 775 supercomputer (with up to 55,000 Power7 cores). I will discuss design and implementation decisions that make it possible to achieve competitive performance at scale while retaining X10's productivity. In particular, I'll describe our implementation of the Unbalanced Tree Search benchmark (UTS), which illustrates X10's handling of irregular parallelism.