Nowadays multicore systems have been used in real-time applications such as robots. In robots, imprecise tasks such as image processing tasks are required to detect and avoid objects. However, existing real-time operating systems have evaluated multiprocessor real-time scheduling algorithms in Liu and Lay land's model and have not evaluated those in the imprecise computation model. This paper performs experimental evaluations of global and partitioned semi-fixed-priority scheduling algorithms in the extended imprecise computation model on multicore systems. Experimental results show that semi-fixed-priority scheduling has comparable overhead to fixed-priority scheduling. In addition, global semi-fixed-priority scheduling has lower overhead than partitioned semi-fixed-priority scheduling.