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Re: Updates to Navigation Timing errata

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Tue, 14 May 2013 12:51:30 -0400
Message-ID: <51926B92.2020402@mit.edu>
To: public-web-perf@w3.org
On 5/14/13 10:49 AM, Philippe Le Hegaret wrote:
> It includes two errata, one regarding the navgiationStart attribute, and
> one regarding the illustration in 5.1 Processing Model.

I hate sounding like a broken record, but this is still assuming a model 
in which "TCP" comes after "DNS" and "DNS" comes after "Prompt for Unload".

In actual browsers, "DNS" can happen when the user hovers over the link 
that they will click to leave the page (before "Prompt for unload") and 
"TCP" can start before "DNS" completes due to speculative preconnects....

As a result, a browser implementing this specification right now has the 
choice of either not following the spec or reporting numbers that don't 
reflect what it actually did.  In practice I believe at least Gecko ends 
up doing a mix of the two depending on where people remembered to put in 
random max() or min() calls; I can't speak to other browsers.

-Boris
Received on Tuesday, 14 May 2013 16:51:59 UTC

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