Date: Thu, 8 Apr 1999 16:41:03 -0700 (PDT) From: Matthew Dillon <dillon@apollo.backplane.com> To: David Greenman <dg@root.com> Cc: "John S. Dyson" <dyson@iquest.net>, aron@cs.rice.edu, freebsd-hackers@FreeBSD.ORG Subject: Re: scheduling queues in FreeBSD Message-ID: <199904082341.QAA15598@apollo.backplane.com> References: <199904082248.PAA21483@implode.root.com>
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:> One thing we could do that would accomplish virtually the same goals would
:> be to 'lock' the cpu priority. This would be a great temporary solution.
:>
:> If the cpu priority is locked into queue 0, we are effectively equivalent
:> to the idle queue. If the cpu priority is locked into queue 31, we are
:> effectively equivalent to the realtime queue. We then reduce the
:> priority range that 'normal' processes are allowed to obtain such that they
:> fall into queues 1-30. Poof, done.
:
: That would probably be adequate, but it does sacrifice the ability to have
:multiple realtime (and idletime) priorities and thus may deminish the
:usefulness of the whole thing even more.
:
:-DG
:
:David Greenman
I think it would be useful for 'idle' priority processes, but I agree
that it would not be useful for any sort of true 'realtime' ( i.e.
when there is more then one realtime process ). But the existing
realtime scheduler isn't useful for true realtime either since there
are no scheduling primitives.
If nobody xxxx not to many people have objections, I would be happy to
remove the realtime & idle queue junk and replace it with the locked
priority concept. ( Cavet: the priority would only be locked while
running in user mode, I wouldn't mess with the supervisor sleep priority
override mechanism ). This would make idle processes useful again.
I would also be happy if someone else did this... but if nobody else
wants to, I can :-)
-Matt
Matthew Dillon
<dillon@backplane.com>
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