RT & REMRT Shared Memory Parallel and Network Distributed Ray-Tracing Programs

Report No. ARL-RP-429
Authors: Michael John Muuss
Date/Pages: April 2013; 18 pages

The ray-tracing procedure is ideal for execution in parallel, both in tightly coupled shared-memory multiprocessors, as well as loosely coupled ensembles of computers. RT, the ray-tracer in the Ballistics Research Laboratory Computer-Aided Design (BRL-CAD) Package, takes advantage of both types of parallelism, using different mechanisms. The presentation will start with a discussion of the structure of the ray-tracer, and the strategies used for operating on shared-memory multiprocessors such as the Denelcor HEP, Alliant FX/8, and Cray X-MP.

The strategies used for dividing the work among network-connected loosely coupled processors will be presented. This will include details of the dispatching algorithm, the distribution protocol designed, and a brief description of the "package" (PKG) protocol which carries the distribution protocol. The presentation will conclude by investigating the performance issues of this type of parallel processing, including a set of measured speeds on a variety of hardware.

Distribution: Approved for public release
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Last Update / Reviewed: April 1, 2013