And my patch *MAKES* it compliant with these definitions. The scheduler
was *NOT* compliant with these definitions.
You've quoted me out of context below. My statement that you quote
applies to SCHED_OTHER processes.
Please see my original post with the patch. And thanks for reinforcing
what I was saying!
- Bhavesh
Richard Seaman, Jr. wrote:
> On Thu, Jun 13, 2002 at 03:14:53PM -0600, Bhavesh P. Davda wrote:
>
>
>>I would think that the logical place to add any process to the runqueue
>>would be the back of the runqueue. If all processes are ALWAYS added to
>>the back of the runqueue, then every process is GUARANTEED to eventually
>>be scheduled. No process will be starved indefinitely.
>
>
> FYI, from SuSv3:
>
> "Under the SCHED_FIFO policy, the modification of the definitional
> thread lists is as follows:
>
> 1. When a running thread becomes a preempted thread, it becomes
> the head of the thread list for its priority.
>
> 2. When a blocked thread becomes a runnable thread, it becomes
> the tail of the thread list for its priority.
>
> ....
>
> 7. If a thread whose policy or priority has been modified other
> than by pthread_setschedprio() is a running thread or is runnable,
> it then becomes the tail of the thread list for its new priority.
>
> 8. If a thread whose policy or priority has been modified by
> pthread_setschedprio() is a running thread or is runnable, the
> effect on its position in the thread list depends on the direction
> of the modification, as follows:
>
> 1. If the priority is raised, the thread becomes the tail of
> the thread list.
> 2. If the priority is unchanged, the thread does not change
> position in the thread list.
> 3. If the priority is lowered, the thread becomes the head
> of the thread list.
>
> 9. When a running thread issues the sched_yield() function, the
> thread becomes the tail of the thread list for its priority.
>
> ...."
>
> Also, regarding SCHED_RR:
>
> "...This policy shall be identical to the SCHED_FIFO policy with the
> additional condition that when the implementation detects that a
> running thread has been executing as a running thread for a time
> period of the length returned by the sched_rr_get_interval() function
> or longer, the thread shall become the tail of its thread list and
> the head of that thread list shall be removed and made a running
> thread......"
>
> I'm not suggesting Linux HAS to comply with these requirements,
> but its worth consideration.
>
-- Bhavesh P. Davda Avaya Inc Room B3-B03 E-mail : bhavesh@avaya.com 1300 West 120th Avenue Phone : (303) 538-4438 Westminster, CO 80234 Fax : (303) 538-3155- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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