Good for machine cycles, floating point operations, cache misses. Parallel overhead generally insignificant. Easy to do and intermediate files are good for spotting possible parallel regions. Manual parallelising code with parallel directives See man mp . Good for writing output to screen in an ungarbled fashion.
Environment variables See man mp .
Code Tuning Steps Optimising code for a single processor Port and debug the code and obtain the correct answers with no optimisations. Use exisiting tuned libraries to increase performance. Inline code and unroll loops. Get any loops in your code to Software Pipeline. Modify your code for better Cache utilisation.