Date: Fri, 12 Feb 2010 11:46:04 -0800 From: Jeremy Chadwick <freebsd@jdc.parodius.com> To: Torfinn Ingolfsen <torfinn.ingolfsen@broadpark.no> Cc: freebsd-stable@freebsd.org Subject: Re: ntpd struggling to keep up - how to fix? Message-ID: <20100212194604.GA73961@icarus.home.lan> In-Reply-To: <20100212174452.2140cd72.torfinn.ingolfsen@broadpark.no> References: <20100211190652.6a66c618.torfinn.ingolfsen@broadpark.no> <20100211192515.GB13854@icarus.home.lan> <20100212132947.eb2af3d0.torfinn.ingolfsen@broadpark.no> <20100212131117.GA51905@icarus.home.lan> <20100212174452.2140cd72.torfinn.ingolfsen@broadpark.no>
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On Fri, Feb 12, 2010 at 05:44:52PM +0100, Torfinn Ingolfsen wrote: > On Fri, 12 Feb 2010 05:11:17 -0800 > Jeremy Chadwick <freebsd@jdc.parodius.com> wrote: > > > Please try doing this: > > > > - stop ntpd > > - rm /var/db/ntpd.drift > > - sysctl kern.timecounter.hardware=ACPI-safe > > - start ntpd > > Thanks, I'm currently testing that. Results in 72 hours (or less) :-) Something else came to mind: some BIOSes let you disable/enable HPET. Often labelled as "High Performance Event Timer" or "Multimedia Timer", you could disable this option then check kern.timecounter.choice to see if HPET is gone from the list. If it is, FreeBSD will very likely choose ACPI-safe as the default timecounter (again, check kern.timecounter.hardware to see what the kernel chose itself. Remember that your sysctl.conf entry will override this though! :-) ), which -- assuming it works -- should solve your problem. Technical footnote: I wish I understood 1) the difference between ACPI-safe and ACPI-fast, and 2) how the system or OS "ranks" the timecounters (the higher the value in parenthesis, supposedly the more accurate/preferred it is). Xin, do you happen to know how this works? -- | Jeremy Chadwick jdc@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |
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