Reducing Shared Cache Misses via dynamic Grouping and Scheduling on Multicores

Abstract

Abstract-Multicore technology enables the system to perform more tasks with higher overall system performance. However, this performance can't be exploited well due to the high miss rate in the second level shared cache among the cores which represents one of the multicore's challenges. This paper addresses the dynamic co-scheduling of tasks in multicore real-time systems. The focus is on the basic idea of the megatask technique for grouping the tasks that may affect the shared cache miss rate ,and the Pfair scheduling that is then used for reducing the concurrency within the grouped tasks while ensuring the real time constrains. Consequently the shared cache miss rate is reduced.The dynamic co-scheduling is proposed through the combination of the symbiotic technique with the megatask technique for co-scheduling the tasks based on the collected information using two schemes. The first scheme is measuring the temporal working set size of each running task at run time, while the second scheme is collecting the shared cache miss rate of each running task at run time.Experiments show that the proposed dynamic coscheduling can decrease the shared cache miss rate compared to the static one by 52%.This indicates that the dynamic coscheduling is important to achieve high performance with shared cache memory for running high workloads like multimedia applications that require real-time response and continuousmedia data types.