Which OS are you on?

If you're on Windows, this is a known phenomena of that module on that platform. From the HiRes.XS:

/* If the performance counter delta drifts more than 0.5 seconds from 
+the
 * system time then we recalibrate to the system time.  This means we 
+may
 * move *backwards* in time! */

[download]

In your scenario, if when then first timestamp is taken, the clock has drifted by more than half a second, then Time::HiRes 'corrects' its internal counter.

Then, when the second timestamp is taken less that half a second later, the time appears to have run backwards by up to half a second.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority". I knew I was on the right track :)
In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re: Time::HiRes gettimeofday producing timestamps out of order by BrowserUk
in thread Time::HiRes gettimeofday producing timestamps out of order by 1nickt

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