Bandwidth measurement using performance counters for predictable multicore software

Memory contention is one of the largest sources of inter-core interference in statically partitioned multicore systems, and the contention reduces the overall performance of applications and causes unpredictable execution-times. A first step in achieving predictable execution is to accurately measure the amount of consumed memory bandwidth for each application. Such measurements can be used to track down bottlenecks, provide better partitioning among cores, and ultimately be used to arbitrate and police access to the memory bus. We propose to use hardware performance counters to continuously track the memory-bandwidth consumed by different applications executing in parallel. In this paper we describe ongoing efforts exploring suitable performance counters on core-level and on system-on-chip level for the 8-core Freescale P4080 processor. The aim is to accurately and efficiently track consumed memory bandwidth per application; with the final goal to use these measurements to improve predictability of multicore realtime software.