On level-1 cache locking for high-performance low-power real-time multicore systems

• Three novel level-1 cache locking strategies for multicore systems are proposed.
• The random locking strategy (memory blocks are chosen randomly) is the simplest one.
• The static and dynamic schemes are based on the worst case execution time analysis.
• The dynamic scheme allows changes during runtime, but the static scheme does not.
• In our experiment, the dynamic scheme outperforms the static and random schemes.

Multiple caches in multicore architecture increase power consumption and timing unpredictability. Although cache locking in single-core systems shows improvement for large multithreaded applications, there is no such effective strategy for multicore systems. In this work, we propose three level-1 cache locking strategies for multicore systems – static, random, and dynamic. In the random strategy, blocks are randomly selected for locking. The static and dynamic schemes are based on the analysis of applications’ worst case execution time (WCET). The static scheme does not allow unlocking blocks during runtime, but the dynamic scheme does. Using VisualSim and Heptane tools, we simulate a system with four cores and two levels of caches. According to the simulation results, the dynamic cache locking strategy outperforms the static and random strategies by up to 35% in mean delay per task and up to 22% in total power consumption for the workloads used (e.g., MPEG3 and MPEG4).

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