W3C

- DRAFT -

Web Performance Working Group Teleconference

10 Oct 2012

See also: IRC log

Attendees

Present
+1.650.253.aaaa, +1.503.264.aabb, +1.650.214.aacc, [Microsoft], Plh, Jatinder, plh, Arvind, Tony, Ganesh
Regrets
Chair
SV_MEETING_CHAIR
Scribe
JatinderMann

Contents


<trackbot> Date: 10 October 2012

Review ‘Status of this Document’ text template

http://lists.w3.org/Archives/Public/public-web-perf/2012Oct/0007.html

Action Philippe to look into updating the 'Status of this Document' template for all Performance specs

<trackbot> Created ACTION-106 - Look into updating the 'Status of this Document' template for all Performance specs [on Philippe Le Hégaret - due 2012-10-17].

Review HRT and Page Visibility Test Cases

http://lists.w3.org/Archives/Public/public-web-perf/2012Oct/0014.html

Jatinder: Per the mailing list comments, we agree to moving test_cross_frame_start.html and monotonic-clock.html to the approved. There is a minor tweak for basic.html.

Philippe: I want to keep a test to check that now() should be on performance.

Jatinder: You can add an additional test that checks if now() exists on performance.

Philippe: Okay.
... Should we remove prefixes in the approved tests?

Jatinder: The approved tests should have the prefixes removed, but for implementation ease, the submitted tests can have the prefixes.

Philippe: That works for me.

Jatinder: Page Visibility: http://w3c-test.org/webperf/tests/submission/Microsoft/PageVisibility/

Moving to HRT to proposed recommendation.

Jatinder: Regarding bringing HRT to Web Workers, we have already discussed that instead of just bringing the performance.now() property to web workers, we are also interested in understanding what it'll mean to move the entire performance property, including the Timing interfaces, to web workers. Those changes will require additional thought and should be covered in V2 of the timing specs. In addition, there may be other web worker specific scenarios th
... charter update and in V2 of the specs.

Philippe: I agree.

Tony: I agree as well.

Philippe: Considering we have two implementations (IE and FF) that pass the test suite, I recommend we move this specification to Proposed Recommendation.
... Does the WG agree?

Jatinder: I agree.

Tony: I agree.

Philippe: Thanks. I will setup a call for PR for next week.

RequestAnimationFrame

http://www.w3.org/2010/webperf/track/actions/31

<plh> action-31?

<trackbot> ACTION-31 -- Cameron McCormack to consider including window.animationStartTime and the requestAnimationFrame() callback timestamp as monotonically increasing clocks, in UTC format with millisecond resolution. -- due 2012-02-29 -- OPEN

<trackbot> http://www.w3.org/2010/webperf/track/actions/31

<plh> issue-4?

<trackbot> ISSUE-4 -- We perhaps should support an element parameter to requestAnimationFrame() -- raised

<trackbot> http://www.w3.org/2010/webperf/track/issues/4

http://www.w3.org/2010/webperf/track/issues/4

Jatinder: There are two parts to this request: define window.animationStartTime and update the rAF callback parameter to be DOMHighResTimeStamp. The second part has been updated in the latest editor's draft. We should close on whether we want animationStartTime or not. animationStartTime has the benefit of helping synchronize multiple animations.

<plh> http://www.useragentman.com/blog/2012/09/23/cross-browser-gpu-acceleration-and-requestanimationframe-in-depth/

<plh> What’s requestAnimationFrame Doing When A Tab’s Not Visible? Depends On The Browser!

<plh> [[

<plh> Note

<plh> The expectation is that the user agent will run tasks from the animation task source at at a regular interval matching the display's refresh rate. Running tasks at a lower rate can result in animations not appearing smooth. Running tasks at a higher rate can cause extra computation to occur without a user-visible benefit.

<plh> ]]

Tony: Is animationStartTime supported in IE10?

JatindeR: Yes it is.

Tony: We should have Jamesr look at this.

http://www.w3.org/2010/webperf/track/issues/5

<plh> http://lists.w3.org/Archives/Public/public-web-perf/2011May/0018.html

Jatinder: Regarding issue 4, I recommend we do not support element parameter. No browser supports the implementation today. If we want to consider this, we can look at in V2.

<plh> http://w3c-test.org/webperf/tests/submission/W3C/NavigationTiming/basic.html

Philippe: I agree. Let's close the issue

Close issue 4

<plh> "Statements of interest will be the basis for the discussion at the Workshop. What performance issues have you faced? What use cases would you like to ensure that implementations support? If you have tests to illustrate an issue or use case, please share them as well."

Philippe: On the issue of requestAnimationFrame behavior when the page is not visible, seems like FF, Chrome and IE have different implementations.

Jatinder: IE does not fire the callbacks when the page is not visible - which is actually the most power efficient option, as there is no benefit to fire callbacks for an animation that a user can't see. For time based animaitons, not firing the callbacks when page is not visible will not impact how the animation would look when the page is visible.
... I believe FF does an expontential backoff. I prefer if the spec is specific on the rate of callback. I'll follow up on the mailing list on this as well.

Close ISSUE-4

<trackbot> ISSUE-4 We perhaps should support an element parameter to requestAnimationFrame() closed

Summary of Action Items

[End of minutes]

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No ScribeNick specified.  Guessing ScribeNick: JatinderMann
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Default Present: +1.650.253.aaaa, +1.503.264.aabb, +1.650.214.aacc, [Microsoft], Plh
Present: +1.650.253.aaaa +1.503.264.aabb +1.650.214.aacc [Microsoft] Plh Jatinder plh Arvind Tony Ganesh

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Found Date: 10 Oct 2012
Guessing minutes URL: http://www.w3.org/2012/10/10-webperf-minutes.html
People with action items: 

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