Abstract: Multiprocessor priority ceiling protocol (MPCP) is a classical suspension-based real-time locking protocol, wildly used in partitioned fixed-priority (P-FP) scheduled multiprocessor/multicore real-time systems. However, prior worst-case task blocking time (WCTBT) analysis is pessimistic, which negatively impacts the system schedulability. Therefore, a novel WCTBT analysis is proposed. In this analysis, a task is modeled to be an alternative sequence of normal and critical section segments. By analyzing the minimum execution time required for a task to request several shared resources, this method improves the accuracy of prior work and provides an upper bound on the cumulative execution time for a task to execute critical sections in any time interval. Schedulability experiments indicate that the proposed method outperforms the existing methods and improves the system schedulability significantly.