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Date:      Mon, 14 Jun 1999 13:42:31 UTC-0700
From:      Mark McCutcheon <mjmccut@cs.ubc.ca>
To:        freebsd-bugs@freebsd.org
Subject:   Re: kern/12022: System clock timewarps
Message-ID:  <"15666*mjmccut@cs.ubc.ca"@MHS>

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John A. Shue <John.Shue@symmetron.com> says:

> It's not just P90s.
> 
> My P100 is showing the same symptoms:
> 
> The BIOS reports the chip as a 100MHz Pentium.
> 
> dmesg says:
>   Timecounter "i8254"  frequency 1193182 Hz
>   Timecounter "TSC"  frequency 79001623 Hz
>   CPU: Pentium/P54C (79.00-MHz 586-class CPU)
>     Origin = "GenuineIntel"  Id = 0x525  Stepping=5
>     Features=0x1bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8>

For what it's worth, on a test network with 6 2+ year old PPro200
machines running FreeBSD v2.2.2 through 3.2-STABLE, any of them
can come up with an erroneous clock frequency on any reboot.  They
don't have APM capable BIOSes.  Normal report:

 FreeBSD 3.2-STABLE #3: Wed Jun  9 13:06:33 PDT 1999
 <compilation information removed>
 Timecounter "i8254"  frequency 1193182 Hz
 Timecounter "TSC"  frequency 199739727 Hz
 CPU: Pentium Pro (199.74-MHz 686-class CPU)
   Origin = "GenuineIntel"  Id = 0x619  Stepping=9
   Features=0xf9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV>

but the TSC frequency has been seen to vary as low as 120MHz.  More
typically it would be around 180MHz.  Rebooting usually results in
the correct result; sometimes a second reboot is required.  This
never happened during the first 1.5 years of operation, but has
become more frequent with time.  No idea why this should appear to
correlate with hardware age....

Mark McCutcheon | UBC High-Speed Networking | <mjmccut@cs.ubc.ca>



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