In order to reduce the influence of the jitter of hard real-time task caused by scheduling to the stability and reliability of device-level operation system

a model with preemption segment threshold -RJPS is presented.According to the effect on jitter and latency brought by threshold and the analysis of the scheduling on this model

minimum threshold assigned algorithms are designed

which are applied for fixed-priority scheduling and fixed-priority scheduling separately.It is shown by simulation experiment that the threshold segmentation scheduling model can effectively reduce the IO jitter of tasks caused by scheduler in the typical scheduling algorithm.