Dangerously Clever X1 Application Tricks
White, Brett James · OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 2004
We describe optimization techniques on the Cray X1 that are either profoundly unportable or counterintuitive. For example, one can use small, static co-arrays, Cray pointers, and the volatile attribute to pass arbitrary high-bandwidth, minimal-latency messages with no procedure-call overhead. Also, it may be advantageous to bring if statements inside do loops for vectorization. This paper describes how and why.