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RE: Resource Timing - What's included

From: Jatinder Mann <jmann@microsoft.com>
Date: Sat, 28 May 2011 00:38:55 +0000
To: "Zhiheng Wang (zhihengw@google.com)" <zhihengw@google.com>, "public-web-perf@w3.org" <public-web-perf@w3.org>
Message-ID: <EE4C13A1D11CFA49A58343DE361B0B0406856F94@TK5EX14MBXC254.redmond.corp.microsoft.com>
Yes, you are correct that we are referring to the HTTP layer. I didn't think anyone would confuse the generic term "networking layer" with the OSI model's network layer, though, we can be more specific. Do you have a proposed text in mind?

As for including load times, I agree with Nic's assessment on http://lists.w3.org/Archives/Public/public-web-perf/2011Mar/0099.html. This spec should focus on giving information that wasn't previous available, like network latency information.  You can already use JavaScript to measure the load times. Further, the loadEventStart/loadEventEnd would only capture a segment of the total load time. E.g., for an IMG, it would only capture the time taken to run the load event handler(s), not the time taken to decode, render or display the IMG.

Thanks,
Jatinder

From: public-web-perf-request@w3.org [mailto:public-web-perf-request@w3.org] On Behalf Of Zhiheng Wang
Sent: Thursday, May 26, 2011 2:29 PM
To: Nic Jansma
Cc: Kyle Simpson; public-web-perf@w3.org
Subject: Re: Resource Timing - What's included

   Digging up this thread again because I still find the current description about this particular issue needs
more clarification.

   "The PerformanceResourceTiming interface must include all resources fetched from the networking layer
by the current browsing context. Resources that are retrieved from the user agent's networking layer cache
must be included in the PerformanceResourceTiming interface."

   By "networking layer" here, we are referring to the HTTP layer as described in
http://www.ietf.org/rfc/rfc2616.txt, correct? This should be made clear so it differentiates itself with the network
layer and transport layer from the OSI model<http://en.wikipedia.org/wiki/OSI_model>.

  By removing "duplicated contents" and loadEventStart/End from RT, we are more focusing on networking stuff.
I am not sure if this is a good direction since what we skip here could be significant to the overall performance
as well, e.g., responseEnd of an iframe could be quite different from the time it's loaded, while it's the later one that
blocks the overall page load.

cheers,
Zhiheng
Received on Saturday, 28 May 2011 00:39:27 GMT

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