Time keeping Issues with the low-resolution TSC timecounter

Ian FREISLICH ianf at clue.co.za
Thu Jun 23 08:21:32 UTC 2011

Jung-uk Kim wrote:
> On Tuesday 21 June 2011 04:53 pm, Jung-uk Kim wrote:
> > Can you please try the attached patch?  It should disable
> > TSC/TSC-low timecounter for your CPU models, I think.
> Sorry, I attached a wrong patch.  Please ignore the previous one and 
> try this, instead.

TSC-low is not presented as an option any more:

CPU: Intel(R) Atom(TM) CPU N270   @ 1.60GHz (1596.03-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0x106c2  Family = 6  Model = 1c  Stepping = 2
  AMD Features2=0x1<LAHF>
  TSC: P-state invariant, performance statistics

Event timer "LAPIC" quality 400
Timecounter "ACPI-fast" frequency 3579545 Hz quality 900
acpi_timer0: <24-bit timer at 3.579545MHz> port 0x408-0x40b on acpi0
atrtc0: <AT realtime clock> port 0x70-0x77 on acpi0
atrtc0: Warning: Couldn't map I/O.
Event timer "RTC" frequency 32768 Hz quality 0
hpet0: <High Precision Event Timer> iomem 0xfed00000-0xfed003ff irq 0,8 on acpi0
Timecounter "HPET" frequency 14318180 Hz quality 950
Event timer "HPET" frequency 14318180 Hz quality 450
Event timer "HPET1" frequency 14318180 Hz quality 440
Event timer "HPET2" frequency 14318180 Hz quality 440
attimer0: <AT timer> port 0x40-0x43,0x50-0x53 on acpi0
Timecounter "i8254" frequency 1193182 Hz quality 0
Event timer "i8254" frequency 1193182 Hz quality 100

kern.timecounter.choice: TSC(-1000) i8254(0) HPET(950) ACPI-fast(900) dummy(-1000000)

Ian Freislich

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