Improving performance on base stations by improving spatial locality in caches

Abstract: For real-time systems like base stations there are time constraints for them to operate smoothly. This means that things like caches which brings stochastic variables will most likely not be able to be added. Ericsson however want to add caches both for the possible performance gains but also for the automatic loading of functions. As it stands, Ericsson can only use direct mapped caches and the chance for cache misses on the base stations is large. We have tried to see if randomness can be decreased by placing code in the common memory. The new placement is based on logs from earlier runs. There are two different heuristic approaches to do this. The first was developed by Pettis \& Hansen and the second was developed by Gloy \& Smith. We also discuss a third alternative by Hashemi, Kaeli \& Calder (HKC) which was not tested. However the results show there are no practical improvements by using code placement strategies.