performance.now() time origin should be equivalent to performance.timing.navigationStart

Confirmed Issue #7167808 • Assigned to Todd R.

Details

Author
Majid V.
Created
Apr 11, 2016
Privacy
This issue is public.
Found in
  • Microsoft Edge
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Reported by 1 person

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Steps to reproduce

According to the spec the time origin for high resolution timestamp should be equivalent to |performance.timing.navigationStart| (at least when navigating between two documents).
This means that I expect the following expression to have an absolute value that is smaller than 2ms (1ms = rounding error upper bound + 1m ~ cost of calling Date.now() and performance.now()):
|(Date.now() - performance.timing.navigationStart) - performance.now()|
In my tests I see a varying value that goes up to 15ms in EdgeHTML. This is unexpected and I believe is incorrect. This simple test page shows this (let it run for multiple reloads to see the effect).
See attached screenshot showing Firefox, Edge, Chrome running the above page on Win 10. Note that I have noticed occasionally an incorrect value in Chrome as well but that is also likely a bug in Chrome as well.
P.S. I originally filed this in old bug tracker but it was closed as I didn’t provide feedback in time. The fact that this issue is happening in Chrome does not actually mean it is not a bug. Unless my reading of the spec is inaccurate.

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