In this paper, the authors propose an efficient real-time scheduling algorithm for multiprocessor platforms. The algorithm is a derivative of the Rate Monotonic (RM) algorithm, with its basis on the portioned scheduling technique. The theoretical design of the algorithms well implementable for practical use. The schedulability of the algorithm is also analyzed to guarantee the worst-case performance. The simulation results show that the algorithm achieves higher system utilizations, in which all tasks meet deadlines, with a small number of preemptions compared to traditional algorithms.