From owner-freebsd-hackers@FreeBSD.ORG  Wed Jul 11 09:42:30 2012
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Sender: Alexander Motin <mavbsd@gmail.com>
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Date: Wed, 11 Jul 2012 12:42:23 +0300
From: Alexander Motin <mav@FreeBSD.org>
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Cc: davide@FreeBSD.org, freebsd-hackers@freebsd.org,
	Paul Albrecht <albrecht@glccom.com>
Subject: Re: kqueue timer timeout period
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Hi.

Historically FreeBSD used completely different hardware time sources for 
time keeping and time events. Not sure about 5%, but the last could be 
less precise in some cases. FreeBSD 9.0, depending on hardware, can be 
more precise because of using same time source in both cases. Also there 
is ongoing GSoC project now by Davide Italiano to handle sub-HZ 
resolution for time events. Present tests show reaching 20 microseconds 
precision; and I think it can be improved further.

-- 
Alexander Motin