Orio

"Orio is a Python framework for transformation and automatically tuning the performance of codes written in different source and target languages, including transformations from a number of simple languages (e.g., a restricted subset of C) to C, Fortran, CUDA, and OpenCL targets. The tool generates many tuned versions of the same operation using different optimization parameters, and performs an empirical search for selecting the best among multiple optimized code variants.

Orio has several code transformation module that have already been implemented and are ready to use. One of the transformation modules is ''loop unrolling'', which is a loop optimization that aims to increase register reuse and to reduce branching instructions by combining instructions that are executed in multiple loop iterations into a single iteration.

To enhance the performance of a program on target architecture, most compilers select the optimal values of program transformation parameters using analytical models. In contrast, Orio adaptively generates a large number of code candidates with different parameter values for a given computation, followed by empirical executions of these code variants on the target machine. Then the code that yields the best performance is chosen. Orio automates such empirical performance tuning process using annotations.

A conceptually straightforward approach to exploring the space of the parameter values is via an exhaustive search procedure. However, this exhaustive approach often becomes infeasible because the size of the search space can be exponentially large. Hence, a proper search heuristic becomes a critical component of an empirical tuning system. In addition to an ''exhaustive search'' and a ''random search'', two effective and practical search heuristic strategies have been developed and integrated into the Orio’s search engine. These heuristics include the ''Nelder-Mead Simplex'' method and ''Simulated Annealing'' method."

http://brnorris03.github.io/Orio/

https://github.com/brnorris03/Orio