From: Zdenek Kabelac <kabi@i.am>
To: ludovic <ludovic.fernandez@sun.com>
Subject: Re: static scheduling - SCHED_IDLE?
Date: Thu, 8 Mar 2001 11:17:39 GMT [thread overview]
Message-ID: <3AA76A53.CEC1B234@i.am> (raw)
In-Reply-To: <3AA6A97A.1EDE6A0B@sun.com>
ludovic wrote:
>
> Oswald Buddenhagen wrote:
> >
> > > 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.
> >
>
> Since the linux kernel is not preemptive, the problem is a little
> bit more complicated; A low priority kernel thread won't lose the
> CPU while holding a lock except if it wants to. That simplifies the
> locking problem you mention but the idea of background low priority
> threads that run when the machine is really idle is also not this
> simple.
You seem to have a sence for black humor right :) ?
As this is purely a complete nonsence
- you were talking about M$Win3.11 right ?
(are you really the employ of Sun ??)
next prev parent reply other threads:[~2001-03-08 11:18 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-03-07 17:40 static scheduling - SCHED_IDLE? Oswald Buddenhagen
2001-03-07 18:04 ` Rik van Riel
2001-03-07 19:20 ` Oswald Buddenhagen
2001-03-07 21:34 ` ludovic
2001-03-08 11:17 ` Zdenek Kabelac [this message]
2001-03-08 11:41 ` Andrew Morton
2001-03-08 13:29 ` Boris Dragovic
2001-03-08 13:44 ` Rik van Riel
2001-03-08 20:19 ` Boris Dragovic
2001-03-08 20:47 ` Rik van Riel
2001-03-09 19:38 ` george anzinger
2001-03-09 20:19 ` Adrian Cox
2001-03-12 18:05 ` Jamie Lokier
2001-03-12 19:37 ` Adrian Cox
2001-03-13 9:40 ` Jamie Lokier
2001-03-10 2:58 ` Rik van Riel
2001-03-09 19:42 ` Jamie Lokier
2001-03-10 3:02 ` Rik van Riel
2001-03-09 20:09 ` Jamie Lokier
2001-03-10 4:56 ` Rik van Riel
2001-03-14 13:19 ` Jamie Lokier
2001-03-15 3:13 ` Rik van Riel
2001-03-14 14:26 ` Philipp Rumpf
2001-03-09 11:26 ` Pavel Machek
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