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Date: Thu, 12 Feb 2004 10:27:53 +1100 (EST)
From: Bruce Evans <bde@zeta.org.au>
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To: Andre Oppermann <andre@freebsd.org>
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cc: Bjorn Eikeland <bjorn@eikeland.info>
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cc: richard@wendland.org.uk
Subject: Re: dummynet = local taffic > 100ms - help!
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On Wed, 11 Feb 2004, Andre Oppermann wrote:

> Richard Wendland wrote:
> > Tom Pavel sent some patches to this list on 14 Jan 2004 that he has been
> > using to overcome this HZ/RFC1323 problem.
>
> I remember some comments (by BDE?) to the effect that the patch is not
> entirely correct.

It was just inelegant.  There are several different tick counters
already active.  None are quite right, but perhaps one could be adapted.
The closest to being right is the implicit one in tc_ticktock().  This
defaults to a period of max(1/1000, 1/HZ) seconds but doesn't guarantee
a period of > 1/1000 seconds since it can be meddled with using the
kern.timecounter.tick sysctl.  There is also the implicit one in
sched_clock().  sched_clock() is supposed to be called every 1/128
seconds (to within a factor of 2).

Bruce