Exploring the Effects of Code Optimizations on CPU Frequency Margins.

Chip manufactures introduce redundancy at various levels of CPU design to guarantee correct operation even for worst-case combinations of non-idealities in process variation and system operation conditions. This redundancy is implemented partly in the form of voltage/frequency margins. However, for a wide range of real-world execution scenarios, these margins are excessive and translate to increased power and energy consumption. Among the various factors that affect the degree to which these margins are actually needed to avoid errors during program execution, the impact of compiler and source code optimizations has not been explored yet. In this work, we study the effect of such optimizations on the frequency margins and the energy efficiency of applications in the ARM Cortex-A53 processor.