From owner-freebsd-hackers@FreeBSD.ORG  Thu Oct  2 21:21:35 2014
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From: John Baldwin <jhb@freebsd.org>
To: freebsd-hackers@freebsd.org
Subject: Re: freebsd 10 kqueue timer regression
Date: Thu, 2 Oct 2014 16:00:17 -0400
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 (bigwig.baldwin.cx); Thu, 02 Oct 2014 17:21:34 -0400 (EDT)
Cc: Adrian Chadd <adrian@freebsd.org>, Paul Albrecht <palbrecht@glccom.com>,
 Ian Lepore <ian@freebsd.org>
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On Thursday, October 02, 2014 3:53:28 pm Ian Lepore wrote:
> On Thu, 2014-10-02 at 12:47 -0700, Adrian Chadd wrote:
> > I'm confused; it's doing 50 loops of a 20msec timer, right? So that's 
1000ms.
> 
> Yes, so the entire loop should take 1000ms maybe + 1ms.  Instead it
> takes 1070.  When I run it on an armv6 system running -current it takes
> 1050.  When I run it on my 8.4 desktop (pre-eventtimers) it takes 1013.
> 
> -- Ian

What if you set kern.eventtimer.periodic=1?

-- 
John Baldwin