[webkit-dev] PSA: higher precision event timestamp landing soon - port verification needed

[Rick Byers]

There's been discussion / patches in the past for exposing system time as a
separate timestamp on the Event object (as IE does).  See
https://lists.webkit.org/pipermail/webkit-dev/2012-October/022574.html,
https://bugs.webkit.org/show_bug.cgi?id=94987 and
http://lists.w3.org/Archives/Public/public-web-perf/2012Oct/0046.html.

In particular, the use of UNIX-epoch timestamps means such measurements
will never be completely accurate (due to NTP skew, leap seconds, etc.).
 But just updating the timestamp everyone uses to be more accurate (even if
not perfect) seems like a clear win.

Do you think both approaches should be pursued, or is updating the existing
timestamp to be as accurate as possible within the epoch semantics good
enough?

Thanks,
 Rick


On Sun, Jun 9, 2013 at 2:30 AM, Benjamin Poulain <benjamin at webkit.org>wrote:

> Hi WebKit,
>
> Next week, I will land a patch changing the way event timestamps are
> handled: https://bugs.webkit.org/show_bug.cgi?id=117179
>
> Previously, the PlatformEvent timestamp was ignored when creating a DOM
> Event, and a new timestamp was generated with currentTime() when the DOM
> Event was created.
> After the change, the timestamp from the PlatformEvent is used for the DOM
> Event.
>
> This change will help web pages to determine the speed and acceleration of
> input with a better accuracy.
>
> The patch of https://bugs.webkit.org/show_bug.cgi?id=117179 updates the
> Mac port to adapt for the changes. The other ports may need to be changed
> as well.
> Please take a minute to check your port, and create a bug blocking 117179
> if needed.
> The timestamp passed to create PlatformEvents must now be the time in
> seconds since Unix Epoch.
>
> Benjamin
>
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