From owner-freebsd-current  Sat Dec 22  0: 6:45 2001
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Date: Sat, 22 Dec 2001 00:06:39 -0800
From: Luigi Rizzo <rizzo@aciri.org>
To: Bruce Evans <bde@zeta.org.au>
Cc: John Baldwin <jhb@FreeBSD.org>, current@FreeBSD.org,
	Peter Wemm <peter@wemm.org>
Subject: Re: vm_zeropage priority problems.
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References: <20011221095058.A17968@iguana.aciri.org> <20011222183040.E7393-100000@gamplex.bde.org>
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On Sat, Dec 22, 2001 at 06:48:26PM +1100, Bruce Evans wrote:
> On Fri, 21 Dec 2001, Luigi Rizzo wrote:
...
> > This would help removing the ugly property that priority-based
> > have, which is that one process can starve the rest of the system.
> 
> Only broken priority-based schedulers have that property.  One of
> my incomplete fixes uses weights:

which makes it weight based, doesn't it :)

> Most of the changes here are to fix style bugs.  In the NEW_SCHED case,
> the relative weights for each priority are determined by the niceweights[]
> table.  kg->kg_estcpu is limited only by INT_MAX and priorities are
> assigned according to relative values of kg->kg_estcpu (code for this is
> not shown).

i guess the latter is the hard part... what kind of complexity does
it have ?

The nice feature of the scheduling code used in dummynet/Wf2Q+ is
that it has O(log N) complexity where N is the number of active
flows (processes in this case) and the basic scheduling operation
is just one or two heap insert/delete, so it's really fast.

	cheers
	luigi

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