This paper presents a new algorithm for scheduling of sporadic task systems with arbitrary deadlines on identical multiprocessor platforms. The algorithm is based on the concept of semi-partitioned scheduling, in which most tasks are fixed to specific processors, while a few tasks migrate across processors. Particularly, we design the algorithm so that tasks are qualified to migrate only if a task set cannot be partitioned any more, and such migratory tasks migrate from one processor to another processor only once in each period. The scheduling policy is then subject to Earliest Deadline First. Simulation results show that the algorithm delivers competitive scheduling performance to the state-ofthe- art, with a smaller number of context switches.