用nice计算static_prio:
#define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
#define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
#define MAX_RT_PRIO MAX_USER_RT_PRIO
#define MAX_USER_RT_PRIO 100