Re: static scheduling - SCHED_IDLE?

From: Oswald Buddenhagen (ob6@inf.tu-dresden.de)
Date: Wed Mar 07 2001 - 14:20:27 EST


> The problem with these things it that sometimes such a task may hold
> a lock, which can prevent higher-priority tasks from running.
>
true ... three ideas:
- a sort of temporary priority elevation (the opposite of SCHED_YIELD)
  as long as the process holds some lock
- automatically schedule the task, if some higher-priorized task wants
  the lock
- preventing the processes from aquiring locks at all (obviously this
  is not possible for required locks inside the kernel, but i don't
  know enough about this)

> A solution would be to make sure that these tasks get at least one
> time slice every 3 seconds or so, so they can release any locks
> they might be holding and the system as a whole won't livelock.
>
did "these" apply only to the tasks, that actually hold a lock?
if not, then i don't like this idea, as it gives the processes
time for the only reason, that it _might_ hold a lock. this basically
undermines the idea of static classes. in this case, we could actually
just make the "nice" scale incredibly large and possibly nonlinear,
as mark suggested.

best regards

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