New Response Time Analysis for PWLP on Multiprocessor Mixed-Criticality Systems

The Preemptable Waiting Locking Protocol (PWLP) is a mainstream real-time resource sharing protocol that provides predictable mutually exclusive access to shared resources. However, the analysis of PWLP can only support traditional real-time systems, preventing its application in mixed-criticality systems (MCS), which are commonly found in realistic real-time applications. In addition, existing analyses are either overly-pessimistic or computationally extensive with optimizations required. To address the above issues, this paper presents a new response time analysis of PWLP on multiprocessor MCS, enhancing both the effectiveness and applicability of PWLP on MCS. The proposed analysis provides fine-grained blocking bounds of PWLP and explicitly considers the varied task execution time under MCS, achieving accurate timing bounds without significantly increasing computation cost. Experimental results show that the proposed analysis outperforms existing analysis by improving the resulting system schedulability with much less computation cost.