Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 1 Jun 2006 14:41:07 -0400
From:      John Baldwin <jhb@freebsd.org>
To:        freebsd-current@freebsd.org
Cc:        Jeremie Le Hen <jeremie@le-hen.org>
Subject:   Re: [fbsd] timer goes sluggish
Message-ID:  <200606011441.07494.jhb@freebsd.org>
In-Reply-To: <20060530223226.GT1890@obiwan.tataz.chchile.org>
References:  <20060529153103.GA17178@obiwan.tataz.chchile.org> <20060530223226.GT1890@obiwan.tataz.chchile.org>

next in thread | previous in thread | raw e-mail | index | archive | help
On Tuesday 30 May 2006 18:32, Jeremie Le Hen wrote:
> Hi,
> 
> On Mon, May 29, 2006 at 05:31:03PM +0200, Jeremie Le Hen wrote:
> > Hi,
> > 
> > I won't write too much, the following session will tell much more:
> > 
> > % jarjarbinks:root# ntpdate -b chronos.cru.fr
> > % 29 May 17:08:44 ntpdate[4254]: step time server 195.220.94.163 offset 
0.000273 sec
> > % jarjarbinks:root# sysctl kern.timecounter.hardware
> > % kern.timecounter.hardware: ACPI-fast
> > % jarjarbinks:root# while : ; do date ; sleep 1 ; done
> > % Mon May 29 17:08:56 CEST 2006
> > % Mon May 29 17:09:03 CEST 2006
> > % Mon May 29 17:09:09 CEST 2006
> > % Mon May 29 17:09:16 CEST 2006
> > % Mon May 29 17:09:22 CEST 2006
> > % ^C
> 
> Sometimes, I feel dumb.
> 
> I noticed that the clock sped up when the CPU makes heavy computing,
> which meant there was some power saving on idleness.
> 
> I dug a bit I found that hw.acpi.cpu.cx_lowest=C4.
> Setting it hw.acpi.cpu.cx_lowest=C1 makes the clock goes ``in time'' :).

If you are using APIC, try disabling APIC and see if it works ok with higher 
Cx states.

-- 
John Baldwin



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200606011441.07494.jhb>