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Every Linux process is always scheduled according to one of the following scheduling classes
SCHED_FIFO
A First-In, First-Out real-time process. When the scheduler assigns the CPU to the process, it leaves the process descriptor in its current position in the runqueue list. If no other higher-priority real-time process is runnable, the process continues to use the CPU as long as it wishes, even if other real-time processes that have the same priority are runnable.
SCHED_RR
A Round Robin real-time process. When the scheduler assigns the CPU to the process, it puts the process descriptor at the end of the runqueue list. This policy ensures a fair assignment of CPU time to all SCHED_RR real-time processes that have the same priority.
SCHED_NORMAL
A conventional, time-shared process.
这里就描述了对不同的进程类型（是否实时）和不同的优先级别会采用不同的调度方式
另外，进程运行过程中的许多资源处理也都是用了RT函数族，而不是常见PC上使用的系统调用
叶浩子 于 2009-11-13 12:09:12发表:
嵌入式LINUX 具有强实时性，即对实时性的要求更高，原生LINUX的实时性是满足不了要求。所以需要对其进程调度算法加以改进。主要是把实时进程的优化级提高，即优化数减少。线程优先级越高，线程越早得到处理机时间片。 我只知道这些了，但是感觉还是不够完整，但是还是不知道要怎么再回答下去了。你们是怎么觉得的呢？？？
zgzzhanzhan 于 2009-11-13 12:04:16发表:
不好意思
嵌入式Linux内核由于工作环境的问题在一些方面要求会比较高
就拿进程调度来说
ULK3中说的
[Copy to clipboard] [ - ]CODE:
Every Linux process is always scheduled according to one of the following scheduling classes
SCHED_FIFO
A First-In, First-Out real-time process. When the scheduler assigns the CPU to the process, it leaves the process descriptor in its current position in the runqueue list. If no other higher-priority real-time process is runnable, the process continues to use the CPU as long as it wishes, even if other real-time processes that have the same priority are runnable.
SCHED_RR
A Round Robin real-time process. When the scheduler assigns the CPU to the process, it puts the process descriptor at the end of the runqueue list. This policy ensures a fair assignment of CPU time to all SCHED_RR real-time processes that have the same priority.
SCHED_NORMAL
A conventional, time-shared process.
这里就描述了对不同的进程类型（是否实时）和不同的优先级别会采用不同的调度方式
另外，进程运行过程中的许多资源处理也都是用了RT函数族，而不是常见PC上使用的系统调用
微宝贝 于 2009-11-13 10:52:09发表:
没有做过软件，我虽然在学嵌入式，但是一直没有涉及软件，应该是一样的。
叶浩子 于 2009-11-13 10:50:52发表:
怎么还是没人回答呀 555、、、
tangkui0528 于 2009-11-13 09:13:03发表:
我也想知道，呵呵
377142617 于 2009-11-13 07:21:03发表:
等
miling 于 2009-11-13 00:05:40发表:
也想知道答案