Date: Sat, 5 Aug 2006 11:01:19 +0200 From: Jeremie Le Hen <jeremie@le-hen.org> To: John Baldwin <jhb@freebsd.org> Cc: freebsd-current@freebsd.org Subject: Re: [fbsd] Re: [fbsd] timer goes sluggish Message-ID: <20060805090119.GM4498@obiwan.tataz.chchile.org> In-Reply-To: <200606011441.07494.jhb@freebsd.org> References: <20060529153103.GA17178@obiwan.tataz.chchile.org> <20060530223226.GT1890@obiwan.tataz.chchile.org> <200606011441.07494.jhb@freebsd.org>
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Hi John, On Thu, Jun 01, 2006 at 02:41:07PM -0400, John Baldwin wrote: > 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. Sorry for the delay. I was indeed using APIC, and got a chance to disable it. I am writing this mail with C4 state set and it works flawlessly: % # sysctl hw.acpi.cpu.cx_lowest % hw.acpi.cpu.cx_lowest: C4 % # while : ; do date ; sleep 1 ; done % Sat Aug 5 10:54:19 UTC 2006 % Sat Aug 5 10:54:20 UTC 2006 % Sat Aug 5 10:54:21 UTC 2006 % Sat Aug 5 10:54:22 UTC 2006 What's the point in disabling apic ? Am I supposed to lose some features along with the apic support removal, or is it something I won't notice ? Thank you. -- Jeremie Le Hen < jeremie at le-hen dot org >< ttz at chchile dot org >
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