RE: Resource Timing Level 1 and beyond

I’m in agreement with all of this.

Nicely done, Philippe!


From: Ilya Grigorik []
Sent: Wednesday, April 27, 2016 3:43 PM
To: Philippe Le Hegaret <>
Cc: public-web-perf <>
Subject: Re: Resource Timing Level 1 and beyond

On Tue, Apr 26, 2016 at 7:52 AM, Philippe Le Hegaret <<>> wrote:
Following last week discussion, I added "Level 1" to Resource Timing with the following:
This specification is ready for wide review, with the following features at risk for the first release:
*    Dependency with Performance Timeline 2, since performance observers are lacking implementations;
*    Dependency with High Resolution Time 2 and workers support, including workerStart, since we're still refining time origin;
*    nextHopProtocol, transferSize, encodedBodySize, and decodedBodySize, since we're currently lacking implementations.

We also had secureConnectionStart marked as optional for a long time and recently changed it to mandatory. My proposal would be to also treat that change as an L2 feature. With these carveouts in place, I think we should have three existing implementations (Edge, FF, Chrome) of proposed L1. And once we land, we can (hopefully :)) confirm that.

Imho, the issue that affects the most implementations at the moment is

I'm proposing that we don't solve it for V1 but keep flagging it as an issue in the spec for Web developers to be aware of.

I agree. The spec did not indicate either way until we landed [1] and I think we can: (a) keep it as such for L1, (b) resolve it in L2. With that in mind, we would probably need to back out that commit for L1?


If we're ok with this, plan is to move a Level 1 version of the spec without the feature at risk and publish at the same time a Level 2 of spec as normal. Level 1 shouldn't impact editors, ongoing issues, or pull requests. The branch gh-pages will continue to hold and will continue to reflect it as a Working Draft. In other words, Level 1 is and should remain a side artifact. We do however have enough implementations of Level 1 to ship to Recommendation within 3/4 months.

sgtm. Much overdue, but better late than never! :)


Received on Thursday, 28 April 2016 00:23:12 UTC