(Dis)Advantages of Lock-free Synchronization Mechanisms for Multicore Embedded Systems

Embedded systems show a tendency of migrating to multicore processors. However, to fully use the potential of multicore processors, it is necessary to partition software into threads that execute concurrently and communicate using shared memory. In order to ensure the correctness and validity of shared data, threads need to synchronize their accesses. Currently prevailing lock-based synchronization introduces new challenges, as the hard-to-predict effect on the worst-case execution time seems to be most severe for embedded systems. Synchronization without locks (mainly lock-free) potentially offers many advantages over lock-based synchronization. In this paper, we investigate relevant aspects of embedded software systems affected by synchronization, including the testing process. We present conclusions in favor of and against migration to lock-free synchronization, including guidelines to help quantify the risks, and the results of applying testing tools to find concurrency bugs in software with lock-free synchronization. We look at the migration from the architectural point of view.