Messages in this thread | | | Date | Fri, 27 Jul 2007 13:56:42 +0200 | From | John Sigler <> | Subject | System clock frequency offset changes drastically across reboots |
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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?
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