Messages in this thread | | | Date | Mon, 03 Sep 2007 12:21:37 +0200 | From | John Sigler <> | Subject | System clock frequency offset changes drastically across reboots |
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[ Re-sending... Please feel free to comment, even if you don't have "The Solution". I'd just like to get some feedback. ]
Hello everyone,
I'm using 2.6.20.7-rt8 on a P3.
I've noticed that the frequency offset of my system clock (computed either by ntpd, or by hand) changes drastically across reboots.
By drastically, I mean +/- 60 ppm every time I reboot.
Apparently this is caused by some imprecision in the frequency estimation done in calculate_cpu_khz() (arch/i386/kernel/tsc.c)
My brutally crude work-around was to skip the computation altogether and hard-code the "correct" value for cpu_khz.
http://linux.kernel.free.fr/cpu_khz.adlink
Has this issue been investigated more thoroughly by other users?
Regards.
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