I-CoPES: fast instruction code placement for embedded systems to improve performance and energy efficiency

The ratio of cache hits to cache misses in a computer system is, to a large extent, responsible for its characteristics such as energy consumption and performance. In recent years energy efficiency has become one of the dominating design constraints, due to the rapid growth in market share for mobile computing/communication/internet devices. We present a novel fast constructive technique that relocates the instruction code in such a manner into the main memory that the cache is utilized more efficiently. The technique is applied as a re-processing step, i.e. before the code is executed. it is applicable for embedded systems where the number and characteristics of tasks running on the system are known a priori. The technique does not impose any computational overhead to the system. As a result of applying our technique to a variety of real-world applications we measured (through simulation) that the number of cache misses drops significantly. Further, this reduces the energy consumption of a whole system (CPU, caches, buses, main memory) by up to 65% at an only slightly increased memory size of 13% on average.