Practical Run-time Adaptation with Procedure Cloning to Enable Continuous Collective Compilation

Iterative feedback-directed optimization is now a popular technique to obtain better performance and code size improvements for statically compiled programs over the default settings in a compiler. The offline evaluation of multiple optimization strategies for a given program is a potentially costly operation. The number of iterations typically grows with the complexity of the program transformation search space, and with the number of input datasets used for performance assessment. In addition, as the behavior of a program can vary considerably across different datasets, it is often preferable to generate different optimization versions, covering the full spectrum of the program’s representative datasets. Continuous and collective optimization are targeted at these issues. Continuous optimization searches for the best program transformation at run-time, taking advantages of the phase behavior of programs to evaluate multiple optimization versions within a single run, and dynamically adapting to changing execution contexts. Collective optimization interleaves optimization iterations with program execution