The way I read the (uncut) man page quote leads me to believe the mentioned drift only occurs when "adjusting the system clock (either manually or by services like ntp)".

At I ran the following code: 

perl -le"use Time::HiRes qw( time ); print time while <>

[download]

I pressed enter at 4:39:00, 4:44:00 and 4:56:00. 

1185395940.27216

1185396239.78586

1185396960.49883

[download]

Time 1 and Time 2:
Clock time difference: 300 seconds
HiRes time difference: 299.5137 seconds
Drift: 0.09726 HiRes second per Clock minute

Time 1 and Time 3:
Clock time difference: 1020 seconds
HiRes time difference: 1020.22667 seconds
Drift: 0.01333 HiRes second per Clock minute

You mentioned a drift of 0.5 HiRes second per Clock minute. I am simply not seeing that. The error is surely due to the variance in my response time.

By the way, old versions of Time::HiRes (< 1.53) had notorisouly bad resolution on Windows. Are you using something recent?

In reply to Re: Time::HiRes (un)reliability in Windows/Cygwin ?? by ikegami
in thread Time::HiRes (un)reliability in Windows/Cygwin ?? by graff

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