Computing Just What You Need: Online Data Analysis and Reduction at Extreme Scales

A growing disparity between supercomputer computation speeds and I/O rates makes it increasingly infeasible for applications to save all results for offline analysis. Instead, applications must analyze and reduce data online so as to output only those results needed to answer target scientific question(s). This change in focus complicates application and experiment design and introduces algorithmic, implementation, and programming model challenges that are unfamiliar to many scientists and that have major implications for the design of various elements of supercomputer systems. I review these challenges and describe methods and tools that various groups, including mine, are developing to enable experimental exploration of algorithmic, software, and system design alternatives.