Bug 216833 - TSC as timecounter makes system lag on Core 2 generation hardware with EARLY_AP_STARTUP
Summary: TSC as timecounter makes system lag on Core 2 generation hardware with EARLY_...
Status: Closed FIXED
Alias: None
Product: Base System
Classification: Unclassified
Component: kern (show other bugs)
Version: CURRENT
Hardware: amd64 Any
: --- Affects Some People
Assignee: freebsd-bugs (Nobody)
URL:
Keywords: regression
Depends on:
Blocks:
 
Reported: 2017-02-05 19:42 UTC by Jia-Shiun Li
Modified: 2017-02-25 08:40 UTC (History)
0 users

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Description Jia-Shiun Li 2017-02-05 19:42:20 UTC 
Originally discussed on freebsd-current@
https://lists.freebsd.org/pipermail/freebsd-current/2017-January/064419.html

Since r310177 enablement of EARLY_AP_STARTUP, system time lags behind on Intel Core 2 generation hardware (family 6 model 17). It happens to me on Intel Pentium T4200 and Core 2 E7400. Larry Rosenman (ler@) also confirmed it happening on Xeon E5410.

Workaround:
- Disable EARLY_AP_STARTUP, or
- sysctl kern.timecounter.hardware=HPET
Comment 1 Jia-Shiun Li 2017-02-25 08:40:05 UTC 
fixed in base r314211.