Priority Mechanism in Linux

Priority Mechanism in Linux

Post by Soohyung Le » Thu, 27 May 1999 04:00:00



The following symbols(variables) are defined in task_struct in
<kernel/sched.c>
   - counter
   - priority
   - rt_priority
and
   - sched_priority ( in sched_param )
.

What the exact meaning of each symbol ?
As far as I know, the 'counter' is for dynamic priority ( by goodness() ) ,
and
priority is somewhat static ( according to the scheduling class ,
e.g. SCHED_OTHER,SCHED_RR,and SCHED_FIFO. )

That's all I know and I want to know more .

Can you tell me the relations between these symbols ?
Can you tell me the mechanism for the tasks' priority and for real-time
tasks ?

I want to know precisely the priority mechanism in Linux .
I really need your help .
Thanks in advance .

- Lee -

 
 
 

Priority Mechanism in Linux

Post by lcku » Sat, 29 May 1999 04:00:00



> The following symbols(variables) are defined in task_struct in
> <kernel/sched.c>
>    - counter

counter variable holds the time in ticks for which the process can still
run.
Scheduler uses the value of counter to select the next process.
counter is something like dynamic priority of a process.

Quote:

>    - priority

Priority holds the static priority of a process.

Quote:

>    - rt_priority

real-time priority, when a process with higher priority will run, all other
process with lower priorities should be aside.

lee

Quote:

> and
>    - sched_priority ( in sched_param )
> .

> What the exact meaning of each symbol ?
> As far as I know, the 'counter' is for dynamic priority ( by goodness() ) ,
> and
> priority is somewhat static ( according to the scheduling class ,
> e.g. SCHED_OTHER,SCHED_RR,and SCHED_FIFO. )

> That's all I know and I want to know more .

> Can you tell me the relations between these symbols ?
> Can you tell me the mechanism for the tasks' priority and for real-time
> tasks ?

> I want to know precisely the priority mechanism in Linux .
> I really need your help .
> Thanks in advance .

> - Lee -