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RE: [HighResTime] Web Worker support

From: Jatinder Mann <jmann@microsoft.com>
Date: Thu, 18 Apr 2013 17:44:38 +0000
To: Ben Vanik <benvanik@google.com>
CC: James Robinson <jamesr@google.com>, public-web-perf <public-web-perf@w3.org>, James Simonsen <simonjam@chromium.org>
Message-ID: <c394884d39b94662ba26e037781bd1fa@BLUPR03MB065.namprd03.prod.outlook.com>

If you're just looking at deltas, differences between two time values, the origin shouldn't matter. Is there a case where deltas wouldn't be good enough and you would want the absolute numbers?

If we were are to provide the origin time as a separate value (e.g., performance.originTime), it would need to be in the same sub-millisecond resolution in order to be comparable with other DOMHighResTimeStamps; the spec currently suggests one thousandth of a millisecond. Double precision may be able to support that for milliseconds since Unix epoch.


From: Ben Vanik [mailto:benvanik@google.com]
Sent: Wednesday, April 17, 2013 4:02 PM
To: Jatinder Mann
Cc: James Robinson; public-web-perf; James Simonsen
Subject: Re: [HighResTime] Web Worker support

Thanks for doing this Jatinder! I'm really excited to see access to performance.now() in workers!

How does one determine the navigationStart-like value for shared workers? In order to try to correlate times between shared workers and the pages that launch them, it's important to be able to map the relative times returned by now.

On Tue, Apr 16, 2013 at 5:05 PM, Jatinder Mann <jmann@microsoft.com<mailto:jmann@microsoft.com>> wrote:
The time immediately before step 1 feels like the appropriate creation time for the worker. If we can get a hook into step 1 put into the Web Workers spec, I can link directly to that definition. I'll file a bug on the editor.


From: James Robinson [mailto:jamesr@google.com<mailto:jamesr@google.com>]
Sent: Tuesday, April 16, 2013 4:56 PM
To: Jatinder Mann
Cc: public-web-perf; James Simonsen

Subject: Re: [HighResTime] Web Worker support

In the line:

For a shared worker<http://www.w3.org/TR/workers/#shared-workers-and-the-sharedworkerglobalscope-interface>, the time origin must be equal to the time of creation of the shared worker.

What is the definition of 'creation of the shared worker'?  I could imagine in the processing model:


that this could be interpreted as a time before or after steps 1, 4, 5, or just before step 8.  I think it needs a better normative reference, although the concept seems fine.

- James

On Tue, Apr 16, 2013 at 4:43 PM, Jatinder Mann <jmann@microsoft.com<mailto:jmann@microsoft.com>> wrote:
I have uploaded High Resolution Time Level 2 specification [1], which now supports performance.now() method in the Web Workers context. Please review the spec and provide feedback.


[1] https://dvcs.w3.org/hg/webperf/raw-file/tip/specs/HighResolutionTime2/Overview.html

From: James Simonsen [mailto:simonjam@chromium.org<mailto:simonjam@chromium.org>]
Sent: Wednesday, February 27, 2013 3:19 PM
To: Jatinder Mann
Cc: public-web-perf
Subject: Re: [HighResTime] Web Worker support

I was thinking just now() for the time being. I think the other stuff gets tricky when you have shared workers.

I guess that means we need to define the 0 value too. I'd vote that it's the worker creation time.


On Wed, Feb 27, 2013 at 3:12 PM, Jatinder Mann <jmann@microsoft.com<mailto:jmann@microsoft.com>> wrote:
I believe updating the spec to support now() in Web Workers isn't hard. The real issue is whether we want to move the entire performance object, all the methods and attributes, or a subset of the performance object to Web Workers as well.

If we feel the Timing specs may not make sense in Web Workers, we'll need to specifically exclude them. I think we should be able to make this change relatively quickly once we have consensus.


From: James Simonsen [mailto:simonjam@chromium.org<mailto:simonjam@chromium.org>]
Sent: Wednesday, February 27, 2013 2:53 PM
To: public-web-perf
Subject: [HighResTime] Web Worker support

Hi guys,

Sorry to raise this again, but we keep getting bugged about it. How hard would it be to add Web Workers to High Res Time? The first edition is already a recommendation, so I think we'd need to create a level 2 spec for it.

Does anyone know how large of a change to the spec it'd be? Is it just a matter of adding one tag to the IDL? If so, it seems like we might be able to do it relatively quickly.

Received on Thursday, 18 April 2013 17:48:09 UTC

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