- 论坛徽章:
- 1
|
关于linux内核进程(线程)的优先级,在include/linux/sched.h文件里有如下描述:
/*
* Priority of a process goes from 0..MAX_PRIO-1, valid RT
* priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH
* tasks are in the range MAX_RT_PRIO..MAX_PRIO-1. Priority
* values are inverted: lower p->prio value means higher priority.
*
* The MAX_USER_RT_PRIO value allows the actual maximum
* RT priority to be separate from the value exported to
* user-space. This allows kernel threads to set their
* priority to a value higher than any user task. Note:
* MAX_RT_PRIO must not be smaller than MAX_USER_RT_PRIO.
*/
#define MAX_USER_RT_PRIO 100
#define MAX_RT_PRIO MAX_USER_RT_PRIO
#define MAX_PRIO (MAX_RT_PRIO + 40)
#define DEFAULT_PRIO (MAX_RT_PRIO + 20)
第一段的意思是:
1.进程的优先级是从0~MAX_PRIO-1;值越高,优先级越低;
2.实时进程的优先级是从0~MAX_RT_PRIO-1;
3.SCHED_NORMAL/SCHED_BATCH进程的优先级是从MAX_RT_PRIO-1~MAX_PRIO-1;
第二段引进了MAX_USER_RT_PRIO,貌似是描述用户进程和内核进程的优先级的关系,
但我看的不是很明白,请有经验的大虾解释下(用户线程的优先级和内核线程的优先级的衡量标准一样么?假如不一样,如何在内核里边得到统一,谢谢!!) |
|