Query about the realtime processes scheduling.

nilesh nilesh.tayade at netscout.com
Thu Aug 18 03:21:54 EDT 2011


On Thursday 18 August 2011 12:18 PM, nilesh wrote:
> Hi,
>
> I am not too familiar with Linux scheduler. What I could understand
> theoretically is - the interactive processes get advantage (-5) in priority.
> And hence the effective priority is higher.
>
> Query:
> Is this true for realtime processes ( with SCHED_FIFO/SCHED_RR policy)
> as well? Could the realtime processes be I/O bound or interactive?
>
Please ignore the post.
I should have looked into the code before posting the query. It looks 
like the bonus/penalty is only for non-realtime tasks.

2101static int effective_prio(struct task_struct *p)
2102{
2103        p->normal_prio = normal_prio(p);
2104        /*
2105         * If we are RT tasks or we were boosted to RT priority,
2106         * keep the priority unchanged. Otherwise, update priority
2107         * to the normal priority:
2108         */
2109        if (!rt_prio(p->prio))
2110                return p->normal_prio;
2111        return p->prio;
2112}
2113

-- 
Thanks,
Nilesh



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