Re: Questions about linux scheduler

[Daniel Rodrick <daniel.rodrick@gmail.com>]

Hi,

>
>> * A lower priority process will run only if there are no runnable
>> processes in priority above it - this automatically means that all RT
>> processes get to run before non-RT processes.
>
> True for RT, not true for non-RT.  In the current scheduler the non-RT
> tasks are stored in a time-ordered structure rather than the 40
> runqueues that were used before.  A non-RT task will run once it becomes
> the most "urgent" task based on its nice level, how much cpu time it
> uses, and how long it's been since it ran last relative to other tasks
> on the system.

One last question ... the nice value of a process never changes
(unless done explicitly using nice system call), right?

Thanks,

Dan