He holds a Michael Faiman and Saburo Muroga Professorship in the Department of Computer Science at the University of Illinois at Urbana-Champaign.
He was the principal investigator (PI) for the software of the petascale Blue Waters system and co-director of the Intel and Microsoft-funded Universal Parallel Computing Research Center (UPCRC).
Until 2001, he was a senior manager at the IBM T.J. Watson Research Center, where he led the Scalable Parallel Systems research group responsible for major contributions to the IBM Scalable POWERparallel and the Blue Gene supercomputers.
He was awarded the Seymour Cray Computer Engineering Award by the Institute of Electrical and Electronics Engineers in 2013 for his "contributions to the research, development, theory, and standardization of high-performance parallel computing, including the IBM RS/6000 SP and Blue Gene system.
He is on the Computing Research Association Board of Directors and the NSF CISE advisory committee.