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Date:      Mon, 13 Dec 2004 15:31:05 -0500 (EST)
From:      Jeff Roberson <jroberson@chesapeake.net>
To:        Julian Elischer <julian@elischer.org>
Cc:        FreeBSD Current <freebsd-current@freebsd.org>
Subject:   Re: cvs commit: src/sys/kern sched_ule.c
Message-ID:  <20041213152556.R60504@mail.chesapeake.net>
In-Reply-To: <41BDEAD1.9060308@elischer.org>
References:  <200412131309.iBDD9XXi045169@repoman.freebsd.org> <20041213082407.U9536@mail.chesapeake.net> <41BDDD5E.9060308@elischer.org> <41BDE477.5050103@freebsd.org> <41BDEAD1.9060308@elischer.org>

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On Mon, 13 Dec 2004, Julian Elischer wrote:

>
> The whole problem that "slots" is trying to solve is to stop a single
> process
> from being able to flood the system with threads and therefore make the
> system
> unfair in its favour.
>
> The "slots" method is really suitable for the 4bsd scheduler but it is
> really
> not so good for ULE (at least I think that there are probably better
> ways that
> ULE could implement fairness).
>
> What I think should happen at this stage is that the inclusion of
> kern_switch.c
> should be replaced by actually copying the contents of that file into
> the two
> schedulers and that they be permitted to diverge. This would allow ULE and
> BSD to be cleaned up in terms of the sched_td/kse hack (where they are in
> fact the same structure, but to keep diffs to a minimum I defined one in
> terms of the other with macros).
>
> It would also allow jeff to experiment absolutly freely on how ULE might
> implement fairness without any constraints of worrying about the BSD
> scheduler, and visa versa.
>
> I have been hesitant to do this because there was some (small) amount of
> work going on in the shared file, but I think it is time to cut the
> umbilical
> cord. If ULE is really fixed then this would be a good time to break
> them apart,
> and delete kern_switch.c (or at least move most of the stuff in it out
> to the
> two schedulers). This would protect ULE from future problems being
> "imported" from BSD for example.
>
> comments?

Why don't we move the ke_procq into the thread and then kern_switch can
remain with the generic runq code?  Then we can move *runqueue into the
individual schedulers.  At least then we won't have to make a copy of the
bit twiddling code.

>
>
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