CFD-beräkningar på parallella processorer – En utvärdering av parallella beräkningar för modellering av rumsbrand med Fire Dynamics Simulator.

This report focuses on CFD-calculations using parallel processors carried out with the software Fire Dynamics Simulator (FDS). From a users point of view the advantages and disadvantages with parallel CFD-calculations were analyzed and evaluated. A simplified me-thod for quantitative evaluation was developed with guidance from ASTM E 1355 whereu-pon relative differences between serial reference scenarios and corresponding parallel cal-culations were quantified and evaluated. Also, aspects like wall clock time speed-ups and the use of hardware resources were evaluated. The purpose of the project was to identify possible sources of error and assess calculation speed-ups as a consequence of distributing calculations over multiple processors and whether these depend on the number of proces-sors used

Hybrid analysis of memory references and its application to automatic parallelization

Executing sequential code in parallel on a multithreaded machine has been an elusive goal of the academic and industrial research communities for many years. It has recently become more important due to the widespread introduction of multicores in PCs. Automatic multithreading has not been achieved because classic, static compiler analysis was not powerful enough and program behavior was found to be, in many cases, input dependent. Speculative thread level parallelization was a welcome avenue for advancing parallelization coverage but its performance was not always optimal due to the sometimes unnecessary overhead of checking every dynamic memory reference. In this dissertation we introduce a novel analysis technique, Hybrid Analysis, which unifies static and dynamic memory reference techniques into a seamless compiler framework which extracts almost maximum available parallelism from scientific codes and incurs close to the minimum necessary run time overhead. We present how to extract maximum information from the quantities that could not be sufficiently analyzed through static compiler methods, and how to generate sufficient conditions which, when evaluated dynamically, can validate optimizations. Our techniques have been fully implemented in the Polaris compiler and resulted in whole program speedups on a large number of industry standard benchmark applications