Improving the WCET computation time by IPET using control flow graph partitioning

Implicit Path Enumeration Technique (IPET) is currently largely used to compute Worst Case Execution Time (WCET) by modeling control flow and architecture using integer linear programming (ILP). As precise architecture effects requires a lot of constraints, the super-linear complexity of the ILP solver makes computation times bigger and bigger. In this paper, we propose to split the control flow of the program into smaller parts where a local WCET can be computed faster - as the resulting ILP system is smaller - and to combine these local results to get the overall WCET without loss of precision. The experimentation in our tool OTAWA with lp_solve solver has shown an average computation improvement of 6.5 times