Barriers to Exascale Computing

The development of an exascale computing capability with machines capable of executing O(1018) operations per second by the end of the decade will be characterized by significant and dramatic changes in computing hardware architecture from current (2012) petascale high-performance computers. From the perspective of computational science, this will be at least as disruptive as the transition from vector supercomputing to parallel supercomputing that occurred in the 1990s. This was one of the findings of a 2010 workshop on crosscutting technologies for exascale computing. The impact of these architectural changes on future applications development for the computational sciences community can now be anticipated in very general terms. While the community has been investigating the road to exascale worldwide in the last several years, there are still several barriers that need to be overcome to obtain general purpose exascale performance. This short paper will summarize the major challenges to exascale, and how much progress has been made in the last five years.