John Gyllenhaal is a computer scientist at Lawrence Livermore National Laboratory (LLNL). He has been cheerfully supporting supercomputer users and helping debug the world's most powerful supercomputers as part of Livermore Computing (LC) since 1999. John's 1997 Ph.D. in EE focused on high-performance processor design that leveraged advanced compiler technology and was earned at the University of Illinois at Urbana-Champaign. John spent much of the 1990s writing compilers, processor simulators, and debugging tools. Much of John's time since then has been spent leading various LLNL efforts to make compilers and development environments more powerful and useful for supercomputer users.