Temperature-Aware Compilation for VLIWProcessors

Abstract

Very long instruction word processors (VLIW) allow to execute multiple instructions in parallel. At the same time VLIW compilers optimize the source code for maximum performance by grouping as many instructions in parallel as possible. This work addresses the problem of thermal- awareness in VLIW compilers with a temperature control and reduction techniques with an objective of minimizing the peak temperature in the VLIW processor's functional units. We present a main approach and compare it with a technique that inserts NOPs in the assembly code to allow the hottest units to cool down. The main technique, called temperature-aware instruction binding technique TemplB, effectively binds the instructions executed in parallel to the coolest possible functional units for a given fixed schedule. It generates, for each instruction in a scheduled instruction word, a priority queue of the coolest functional units that can execute the instruction, and rebinds it to the coolest possible unit, considering the temperature as well as the power consumed by the instruction. From experimentation using a set of benchmark designs, it is confirmed that our temperature reduction technique is effective, lowering down the peak temperature of the initial design by up to 13.82% by TemplB.