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Re: requestEnd property for resource timing

From: Philippe Le Hegaret <plh@w3.org>
Date: Wed, 02 May 2012 10:05:59 -0700
To: Matthias Jakel <matthiasjakel@googlemail.com>
Cc: public-web-perf@w3.org
Message-ID: <1335978359.2706.25.camel@chacal>
On Tue, 2012-05-01 at 23:05 +0200, Matthias Jakel wrote:
> i have read the resource timing draft and i suggest to add the
> "requestEnd" attribute to the PerformanceEntry interface to be able to
> calculate the time the server needs to respond with the first byte. If
> you use the chrome developer tools and use the network tab you can see
> the "waiting" time which you could calculate from requestEnd and
> responseStart attributes. without the requestEnd attribute calculating
> the waiting time seems not to be possible.

I believe the reason not to have it is similar to the reason we don't
have one in Navigation Timing:
[[
This interface does not include an attribute to represent the completion
of sending the request, e.g., requestEnd.

      * Completion of sending the request from the user agent does not
        always indicate the corresponding completion time in the network
        transport, which brings most of the benefit of having such an
        attribute.
      * Some user agents have high cost to determine the actual
        completion time of sending the request due to the HTTP layer
        encapsulation.
]]
http://www.w3.org/TR/navigation-timing/#sec-navigation-timing-interface

Philippe
Received on Wednesday, 2 May 2012 17:06:18 UTC

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