[ntp:questions] reference clock, shm and ntpd

Stuart Maclean stuart at apl.washington.edu
Mon Jul 25 22:43:01 UTC 2016


All, please disregard my previous email about ntpd setting tick=freq=0
in the struct timex passed to adjtimex system call.  A more
representative call to adjtimex contains these values:

adjtimex({modes=ADJ_OFFSET|ADJ_MAXERROR|ADJ_ESTERROR|ADJ_STATUS|ADJ_TIMECONST,
offset=32390, freq=33554432, maxerror=35039, esterror=7301,
status=STA_PLL, constant=0, precision=1, tolerance=33554432,
time={1469486352, 424327}, tick=10000, ppsfreq=0, jitter=200, shift=2,
stabil=33554432, jitcnt=0, calcnt=0, errcnt=0, stbcnt=0}) = 0 (TIME_OK)

The freq value of 33million+ corresponds to a ppm value of 512, which is
above the 500 limit that the adjtimex system call expects.  I should
point out again that I am on a legacy 2.6.10 Linux kernel.  Perhaps my
kernel is simply not compatible with a recent ntpd codebase.

Stuart


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