Here's another measurement.. how often DateAndTime now drifts from system time.
(put this method on DateAndTime class side)
calculateDrift
| durationSinceEpoch systemSeconds milSince secDrifted
systemSecondsSinceMidnight |
"those two must be close to minimize time distance between measurement"
systemSeconds := Time primSecondsClock.
" uncomment to see that drift calculation is correct
(Delay forSeconds: 5) wait.
"
milSince := self milliSecondsSinceMidnight.
secDrifted := milSince // 1000.
durationSinceEpoch := Duration
days: SqueakEpoch
hours: 0
minutes: 0
seconds: systemSeconds.
systemSecondsSinceMidnight := durationSinceEpoch -
(durationSinceEpoch days days).
^(Duration seconds: secDrifted) - systemSecondsSinceMidnight
============
Now the experiment, we run this stuff in a tight loop and see
how many times the drift (expressed in seconds is non-zero):
| count |
count := 0.
1 to: 1000000 do: [:i | DateAndTime calculateDrift isZero ifFalse: [
count := count +1 ] ].
count / 1000000 asFloat
0.00142
So, "statistically" every ~1000'th request. "DateAndTime now" is wrong
by 1 second than
system time..
--
Best regards,
Igor Stasenko.
