Samuel Williams is a senior scientist in the Performance and Algorithms Research Group at the Lawrence Berkeley National Laboratory (LBNL). His research interests include high-performance computing, performance modeling, auto-tuning, computer architecture, and hardware/software co-design. Dr. Williams received his Ph.D. in Computer Science from the University of California at Berkeley (UCB) in December of 2008 and his masters in December of 2003. During this period, his doctoral research focused on multicore architectures and automated performance tuning under the guidance of David Patterson. To that end, he created the Roofline model to enable developers, computer scientists, computer architects, and applied mathematicians to assess performance bottlenecks quickly and visually on multicore, manycore, and GPU-accelerated systems.