Data re-allocation enabled cache locking for embedded systems

Cache locking is a cache management technique to preclude the replacement of locked contents. Cache locking methods have been proposed to improve predictability and worst-case execution time (WCET) previously. Recently, instruction cache locking has also been applied to improve average-case execution time (ACET). However, we observe that the previous ACET-driven instruction cache locking technique shows very limited improvement on performance when applied in data cache. The underlying reason lies in that object similarity of data accesses in data memory blocks are relatively low. This paper presents a data re-allocation enabled cache locking framework where data objects are first re-allocated to enhance data object similarity in memory blocks and then a data cache locking is well motivated. In this way, locking efficiency for data cache can be enhanced and thus system performance can be improved. The experimental results show that the miss rate, memory access cycles and dynamic energy can obtain good improvements across a suite of benchmarks.