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Re: Unified Timing Proposal

From: Zhiheng Wang <zhihengw@google.com>
Date: Wed, 20 Apr 2011 12:59:48 -0700
Message-ID: <BANLkTimY_hUU+9i35rOQqVe3E0FzgQ4ZvA@mail.gmail.com>
To: James Simonsen <simonjam@chromium.org>
Cc: public-web-perf <public-web-perf@w3.org>
     Like Nic said, this proposal certainly provokes lots of thoughts.
Thanks to James and Tony.

On Mon, Apr 11, 2011 at 9:29 PM, James Simonsen <simonjam@chromium.org>wrote:

> On Fri, Mar 11, 2011 at 2:09 PM, James Simonsen <simonjam@chromium.org>wrote:
>
>> One of the things that's bothered me about the various timing specs is
>> that each has its own separate interface, despite each basically doing the
>> same thing. I've come up with a proposal for unifying Navigation Timing,
>> Resource Timing, and User Timing under a single interface. Take a look and
>> let me know what you think.
>>
>
> Tony and I spent some time cleaning up the Unified Timing proposal. We've
> come up with an API that uses the same concepts, but is much cleaner. I
> think this will make it a lot more appealing. Please take a look at it and
> let us know what you think.
>
> Thanks,
> Tony and James
>
> API
> [Supplemental] interface Performance {
>   readonly attribute PerformanceLog log;
> };
>
> interface PerformanceLog {
>   const unsigned short LOG_ALL = 0;
>   const unsigned short LOG_RESOURCE = 1;
>   const unsigned short LOG_APP = 2;
>
>   void record(in unsigned short type,
>               in optional unsigned short maxLength);
>   void stop(in unsigned short type);
>
>   const DOMString MARK_FULLY_LOADED = “fullyLoaded”;
>   void mark(in DOMString objectKey,
>             in optional DOMString timingKey);
>
>   void clear(in optional unsigned short type);
>
>   Object getTimings(in optional DOMString objectKey);
>   Object getDurations(in optional DOMString objectKey);
> };
>
> record
>
> Starts or resumes recording of the given log type.
>
> LOG_RESOURCE: An entry will be added to the log for every downloadable
> resource requested after this method is called. The objectKey will be the
> URL of the resource. A timingKey will always be added for fetchStart and
> fetchEnd. If the domain of the resource is the same as the domain of the
> root document, an additional timingKey will be added for: redirectStart,
> redirectEnd, domainLookupStart, domainLookupEnd, connectStart, connectEnd,
> secureConnectionStart, requestStart, responseStart, responseEnd.
>
> LOG_APP: The mark() method behaves as described below.
>
> LOG_ALL: Represents the union of LOG_RESOURCE and LOG_APP.
>
> The number of entries returned by getTimings() and getDurations() is
> limited to maxLength. If maxLength isn’t specified, the default is 1,000
> entries.
>
> By default, the log starts in LOG_APP mode.
>
> stop
>
> Stops recording of the given log type.
>
> LOG_RESOURCE: An entry for each downloadable resources requested after
> this method is called will no longer be added to the log.
>
> LOG_APP: The mark() method becomes a no-op.
>
> LOG_ALL: Represents the union of LOG_RESOURCE and LOG_APP.
>
> mark
>
> Adds an entry of type LOG_APP to the log. The objectKey is the name of the
> key of the entry. This method may be called multiple times with the same
> key.
>
> If a timingKey is not given, it will default to “value”. The timestamp
> associated with this key will be the current time accurate to within 1ms.
>
> clear
>
> Removes all entries of type from the log.
>
> getTimings
>
> Returns an Object in JavaScript Object Notation (JSON) form consisting of
> all entries in the log. If an objectKey is given, only the matching entry
> is returned. The returned object adheres to the following JSON
> specificationn.
>
> {
>
>  “objectKey1”: [{
>
>    “timingKey1”: Integer,
>
>    “timingKey2”: Integer,
>
>    ...
>
>  }],
>
>  “objectKey2”: [{
>
>    “timingKey1”: Integer,
>
>    “timingKey2”: Integer,
>
>    ...
>
>  }],
>
>  ...
>
> }
>
> getDurations
>
> Returns an Object in JavaScript Object Notation (JSON) form consisting of
> the value of the minimum timingKey subtracted from the maximum timingKeyfor each entry in the log. If an
> objectKey is given, only the matching entry is returned. The returned
> object adheres to the following JSON specification.
>
> {
>
>  “objectKey1”: Integer,
>
>  “objectKey2”: Integer,
>
>  ...
>
> }
>

   For example, image search likes to measure the time for the users to see
the fist 1, 5, and 10 images on the result page. How they should do it with
getDurations()?



> Examples
> Resource timing
>
> <script>
>   performance.log.record(performance.log.LOG_RESOURCE);
> </script>
> <img src="http://example.com/foo.gif">
> <script src="http://example.com/foo.js"></script>
>
> > performance.log.getTimings()
> {
>   "http://example.com/foo.gif": [{fetchStart: 100, fetchEnd: 200}],
>   "http://example.com/foo.js": [{fetchStart: 101, fetchEnd: 201}]
> }
> > performance.log.getTimings("http://example.com/foo.gif")
> [{fetchStart: 100, fetchEnd: 200}]
> > performance.log.getDurations()
> {
>   "http://example.com/foo.gif": [100],
>   "http://example.com/foo.js": [100]
> }
> > performance.log.getDurations("http://example.com/foo.gif")
> [100]
>
> User timing (measure style)
>
> <script>
>   performance.log.mark("readEmail", "start");
>   readEmail();
>   performance.log.mark("readEmail", "stop");
> </script>
>
> > performance.log.getTimings()
> {"readEmail": [{start: 123, end: 456}]}
> > performance.log.getDurations()
> {"readEmail": [333]}
> > performance.log.getDurations("readEmail")
> [333]
>
> User timing (mark style)
>
> <script>
>   document.onclick = function() {
>     performance.log.mark("clickTime")
>   }
> </script>
>
> > performance.log.getTimings()
> {“clickTime”: [{value: 123}, {value: 234}]}
>

   How do we get two timing keys with one mark() in this example?


cheers,
Zhiheng



>
> > performance.log.getTimings(“clickTime”)
> [{value: 123}, {value: 234}]
> > performance.log.getDurations()
> {“clickTime”: [0, 0]}
>
Received on Wednesday, 20 April 2011 20:00:15 UTC

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