One of our servers leaped forward again. The interesting part is that the leap is almost identical to a previous leap. Last time it leaped forward by 30944 seconds, and this time by 30961 seconds. Performance frequency is 3579545.
Since these two leaps are very close, I have a feeling it's not some a random error, but rather a calculation error. It's possible that Windows/Linux were loaded at time of leap.
I went over some of the code and found that co_div64() isn't accurate (!), although I couldn't explain the leap by this bug.
For example, co_div64(0x100000000,0x10000000) returns 15 instead of 16. co_div64(0x1000000000000,0x10000000) returns 983055 instead of 1048576.
I'm sure you'll find more accurate algorithms.
Could you also go over relevant code and see if you notice any overflow, signed/unsigned error that can explain the leap with the above data? Would it be possible to to get a debug version to get more information next time the problem occurs?