Dynamic Shared SPM Reuse for Real-Time Multicore Embedded Systems

Allocating the scratchpad memory (SPM) space to tasks is a challenging problem in real-time multicore embedded systems that use shared SPM. Proper SPM space allocation is important, as it considerably influences the application worst-case execution time (WCET), which is of great importance in real-time applications. To address this problem, in this article we present a dynamic SPM reuse scheme, where SPM space can be reused by other tasks during runtime without requiring any static SPM partitioning. Although the proposed scheme is applied dynamically at runtime, the required decision making is fairly complex and hence cannot be performed at runtime. We have developed techniques to perform the decision making offline at design time in the form of optimization problems combined with task scheduling/mapping. The proposed work is unlike previous works that either exploit static schemes for SPM space allocation or perform task scheduling/mapping and SPM space allocation incoherently. The experimental results show that our dynamic SPM reuse scheme can reduce WCET by up to 55% as compared to recent previous works on SPM allocation in real-time multicore embedded systems.