The processor dynamic voltage and frequency scaling(DVFS)leads to unequal performance loss for concurrently running tasks in Linux, affecting the fairness of CPU sharing. This paper proposes a dynamic time-slice scaling scheme to improve the fairness of CPU sharing for concurrently running tasks. The method which is implemented based on Linux task scheduler dynamically scales the length of time-slice for each task using a time-slice scaling factor which is calculated based on the processor performance monitoring unit statistics. Experiment results show that dynamic time-slice scaling scheme can significantly improve the fairness of the CPU sharing with low overhead compared with the conventional Linux scheduler algorithm.