TSC as timecounter makes system lag
jiashiun at gmail.com
Fri Jan 13 00:26:36 UTC 2017
since 2 or 3 weeks ago, I noticed that my old Penryn-based Intel Pentium
T4200 notebook lagged a lot. System time was running a lot slower,
sometimes even looked like it freezed. Keystroke repeat rate was slow too.
Since system time is slow, I tried to change timecounter from default TSC
to HPET. And it resumed normal immediately.
The same world binary works fine on other Ivybridge and Haswell desktops,
so I assume this may be related to CPU or mainboard generations.
FreeBSD jsli-nb 12.0-CURRENT FreeBSD 12.0-CURRENT #0 r311687: Mon Jan 9
04:07:27 CST 2017
jsli at 4cbsd:/personal/freebsd/obj/x64/personal/freebsd/fbsdsrc/sys/MINIMAL-NODEBUG
and CPU is
CPU: Pentium(R) Dual-Core CPU T4200 @ 2.00GHz (1995.04-MHz K8-class
Origin="GenuineIntel" Id=0x1067a Family=0x6 Model=0x17 Stepping=10
TSC: P-state invariant, performance statistics
Tested similar OS rev on another Intel Core 2 Duo E7400 Wolfdale (the same
generation as the Pentium T4200). The same lag also happens on it.
BTW on both system, cpuX:timer interrupts do not fire at all and count
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