内核调度【一】【set_load_weight】

基于androidq的code来看内核调度

2、set_load_weight

static_prio：静态优先级是和nice关联的一个值

静态优先级不会随时间改变，内核不会主动修改它，只能通过系统调用 nice 去修改 static_prio，MAX_RT_PRIO的值是100，static_prio的取值范围是100～139

int prio = p->static_prio - MAX_RT_PRIO; 刚好找到对应的sched_prio_to_weight中的值，所以static_prio

task处于idle状态，他的优先级是固定的3，inv_weight也是固定的

/*
 * To aid in avoiding the subversion(颠覆) of "niceness" due to uneven(不均匀) distribution(分配)
 * of tasks with abnormal(不正常的) "nice" values across CPUs the contribution(贡献) that
 * each task makes to its run queue's load is weighted according to its
 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
 * scaled version of the new time slice allocation that they receive on time
 * slice expiry(到期) etc.
 */

#define WEIGHT_IDLEPRIO                3  

#define WMULT_IDLEPRIO