Before revision:  Beyond bounded job workload, the asymptotic optimality of M-SRPT also holds for unbounded job size distributions with certain probabilistic assumptions, for example, M/M/N system with upper bounded task workload.
After revision:  Beyond bounded job workload, the asymptotic optimality of M-SRPT also holds for infinite job size distributions with certain probabilistic assumptions, for example, M/M/N system with upper bounded task workload.