Time keeping Issues with the low-resolution TSC timecounter

Jung-uk Kim jkim at FreeBSD.org
Thu Jun 23 15:25:45 UTC 2011


On Thursday 23 June 2011 04:21 am, Ian FREISLICH wrote:
> 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
> Features=0xbfe9fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTR
>R,PGE,MCA,CMOV,PAT,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
> Features2=0x40c39d<SSE3,DTES64,MON,DS_CPL,EST,TM2,SSSE3,xTPR,PDCM,M
>OVBE> 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)

It's already committed (r223426).

Thanks!

Jung-uk Kim


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