edaf420fdc
I ran into this problem on a system that was unable to obtain NTP sync
because the clock was running very slow (over 10000ppm slow). ntpd had
declared all of its peers 'reject' with 'peer_dist' reason.
On investigation, the tsc_khz variable was significantly incorrect
causing xtime to run slow. After a reboot tsc_khz was correct so I
did a reboot test to see how often the problem occurred:
Test was done on a 2000 Mhz Xeon system. Of 689 reboots, 8 of them
had unacceptable tsc_khz values (>500ppm):
range of tsc_khz # of boots % of boots
---------------- ---------- ----------
< 1999750 0 0.000%
1999750 - 1999800 21 3.048%
1999800 - 1999850 166 24.128%
1999850 - 1999900 241 35.029%
1999900 - 1999950 211 30.669%
1999950 - 2000000 42 6.105%
2000000 - 2000000 0 0.000%
|
||
---|---|---|
.. | ||
boot | ||
crypto | ||
ia32 | ||
kernel | ||
lguest | ||
lib | ||
mach-default | ||
mach-es7000 | ||
mach-generic | ||
mach-visws | ||
mach-voyager | ||
math-emu | ||
mm | ||
oprofile | ||
pci | ||
power | ||
vdso | ||
video | ||
xen |