Howison, MarkBethel, E. WesChilds, HankJames Ahrens and Kurt Debattista and Renato Pajarola2014-01-262014-01-262010978-3-905674-21-71727-348Xhttps://doi.org/10.2312/EGPGV/EGPGV10/001-010This work studies the performance and scalability characteristics of hybrid parallel programming and execution as applied to raycasting volume rendering a staple visualization algorithm on a large, multi-core platform. Historically, the Message Passing Interface (MPI) has become the de-facto standard for parallel programming and execution on modern parallel systems. As the computing industry trends towards multi-core processors, with fourand six-core chips common today and 128-core chips coming soon, we wish to better understand how algorithmic and parallel programming choices impact performance and scalability on large, distributed-memory multi-core systems. Our findings indicate that the hybrid-parallel implementation, at levels of concurrency ranging from 1,728 to 216,000, performs better, uses a smaller absolute memory footprint, and consumes less communication bandwidth than the traditional, MPI-only implementation.Categories and Subject Descriptors (according to ACM CCS): D.1.3 [Programming Techniques]: Concurrent Programming-Parallel programming, F.1.2 [Computation by Abstract Devices]: Modes of Computation- Parallelism and concurrency, I.3.3 [Computer Graphics]: Picture/Image Generation-Display algorithms