Software Development on Quest

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Stuck? Need help? quest-help@northwestern.edu Single core optimization • Compilers can perform significant optimization if, o Code is structured to make apparent what the compiler should do o Use simple language constructs (e.g. don't use pointers) • Use latest compilers o Check compiler options o Look for architecture specific options • Experiment with different options • May need routine-specific options
Ideal for large codes, with many branches, which are less computationally intensive Ideal for codes containing short loops which are executed regularly Stuck? Need help? quest-help@northwestern.edu Optimization level O(n) ref: Intel optimization manual • -O0: no optimizations, use for debugging. • -O1: optimize for speed, but disable optimizations which increase code size. o Algebraic identity removal o Common subexpression elimination o Constant folding o Redundant load and store elimination • -O2: perform optimizations that the compilers considers the best combination for compilation speed and runtime performance. example: software pipelining. o Inlining o Constant propagation o Loop unrolling o Vectorization o Strength reduction o Dead code elimination o Global register allocation
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Page 13 and 14: Best for codes which are floating p
Page 17 and 18: program MAIN integer::ndim=2,niter=
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Software Development on Quest

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