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Re: [ResourceTiming] A few small things

From: James Simonsen <simonjam@chromium.org>
Date: Tue, 13 Sep 2011 15:03:45 -0700
Message-ID: <CAPVJQimRwDaZKU5HD6OEw374DEM_bEYOh0fs1sdQatWM++XObg@mail.gmail.com>
To: "public-web-perf@w3.org" <public-web-perf@w3.org>
On Tue, Sep 13, 2011 at 2:43 PM, Nic Jansma <Nic.Jansma@microsoft.com>wrote:

>  Hi folks,****
>
> ** **
>
> A few thoughts about the current draft @
> http://www.w3c-test.org/webperf/specs/ResourceTiming/****
>
> ** **
>
> 1. We've discussed the differences between ResourceTiming's startTime<http://www.w3c-test.org/webperf/specs/ResourceTiming/#performance-resource-timing>and
> fetchStart<http://www.w3c-test.org/webperf/specs/ResourceTiming/#fetch-start>before, but I think there is still a bit of confusion.  Ignoring redirects
> for a moment, startTime is currently defined as "The startTime attribute
> must return the time immediately before the user agent starts to queue the
> resource for fetching".  In a recent discussion with James [1], we talked
> about startTime always equaling fetchStart for non-redirection scenarios.
> However, we had also previously talked about startTime possibly being
> earlier than fetchStart, in the case that the browser queued a resource for
> download but does not immediately attempt to fetch it because of connection
> limits.  For example, if you included 100 <img>s all on the same domain, the
> resources may all have a similar startTime (parsing HTML is fast), but their
> fetchStarts would differ on the later <img>s as connections became
> available.  I believe the wording of startTime in the spec currently
> supports this notion, but I wanted to make sure everyone agreed that was the
> intention?
>

I hadn't been thinking about that. This does seem like good information and
the gap between startTime and fetchStart seems like an intuitive way of
exposing it.


> **
>
> 2. For consistency, can we rename INITIATOR_IMAGE<http://www.w3c-test.org/webperf/specs/ResourceTiming/#sec-window.performance-attribute>to INITIATOR _IMG?  All of the other initiator names use the HTML element
> name or concept, and IMAGE seems a bit ambiguous when it really only means
> the <IMG> tag.****
>
> **
>

Sure.

3.  The most popular
initiator<http://www.w3c-test.org/webperf/specs/ResourceTiming/#sec-window.performance-attribute>that
I see on the web that currently falls under INITIATOR_OTHER is
> input[type='image'].  The second most popular is body[background='...'].  We
> could add INITIATOR_INPUT and INITIATOR_BODY, though I don't feel strongly
> that we need them.
>

It's good that you collected data for these. I suspect they're a very small
fraction of the total uses, so I'd vote for leaving them as OTHER. If a lot
of people complain, we can spec them in v2.

James
Received on Tuesday, 13 September 2011 22:04:14 UTC

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