Bug 127484
| Summary: | [timecounters] Drift problem with FreeBSD 7.0 and 7.1 PRERELEASE | ||
|---|---|---|---|
| Product: | Base System | Reporter: | Torbjorn Granlund <tg.at.swox.com> |
| Component: | amd64 | Assignee: | freebsd-amd64 (Nobody) <amd64> |
| Status: | Closed FIXED | ||
| Severity: | Affects Only Me | ||
| Priority: | Normal | ||
| Version: | Unspecified | ||
| Hardware: | Any | ||
| OS: | Any | ||
|
Description
Torbjorn Granlund
2008-09-18 22:40:01 UTC
Hello, I'm experiencing the exact same issue on 7.0/amd64. I have an Asrock A780FullDisplayPort mainboard (with an AMD Athlon64 X2 CPU, CnQ disabled, so the CPU doesn't throttle and always runs at 2.0Ghz, tested with both ACPI HPET enabled and disabled in bios), and looking at NTP it appears my clock is between 1-3 seconds slow each time it synchronizes. kern.timecounter.choice: TSC(-100) HPET(900) ACPI-safe(850) i8254(0) dummy(-1000000) I tried setting kern.timecounter.hardware to HPET (default), ACPI-safe and i8254. Neither of these solved the issue. I also set kern.hz=100 which didn't solve the issue either. 27 Sep 08:52:07 ntpd[761]: ntpd exiting on signal 15 27 Sep 08:53:25 ntpd[761]: synchronized to 194.171.167.130, stratum=1 27 Sep 08:53:27 ntpd[761]: time reset +1.365546 s 27 Sep 08:54:38 ntpd[761]: synchronized to 194.171.167.130, stratum=1 27 Sep 09:08:46 ntpd[761]: synchronized to 194.109.153.91, stratum=3 27 Sep 09:08:48 ntpd[761]: synchronized to 194.171.167.130, stratum=1 27 Sep 09:16:20 ntpd[761]: time reset +2.359489 s 27 Sep 09:16:20 ntpd[761]: kernel time sync enabled 2001 27 Sep 09:17:32 ntpd[761]: synchronized to 194.109.153.91, stratum=3 27 Sep 09:17:32 ntpd[761]: synchronized to 194.171.167.130, stratum=1 27 Sep 09:30:40 ntpd[761]: synchronized to 194.171.167.130, stratum=1 27 Sep 09:38:10 ntpd[761]: time reset +2.907558 s 27 Sep 09:39:21 ntpd[761]: synchronized to 194.171.167.130, stratum=1 Best regards, Paul van Berlo Hi, the issue I was seeing is solved. It appears this is due to a specific BIOS setting (FSB Spread Spectrum), which was set to 'Auto' in my case. I disabled this, and now my clock runs absolutely fine. There should not be any side effects with disabling this option AFAIK. Thanks. Best regards, Paul van Berlo "Paul van Berlo" <pvanberlo@fastmail.fm> writes: the issue I was seeing is solved. It appears this is due to a specific BIOS setting (FSB Spread Spectrum), which was set to 'Auto' in my case. I disabled this, and now my clock runs absolutely fine. There should not be any side effects with disabling this option AFAIK. =20=20 Thanks! My ASUS board didn't have any such option, but it had some "Overclocking" option which was set to "Auto". I changed this to "Standard". The clock now runs about 20 times closer to reality, which is enough for ntpd to work. I wonder if there is anything FreeBSD can do to work around these silly overclock options. One would really wish the BIOS defaults would be more conservative, and leave it to the tinkerers to play around with overclock options. --=20 Torbj=F6rn On some AMD chipsets enabling Spread Spectrum makes HPET to run few percents slower then reported by hardware. It is official chipset errata and it should be handled by BIOS SMI code. -- Alexander Motin State Changed From-To: open->closed Hardware issue. Not a FreeBSD bug. |