Optimize rendering 3p ads in AMP

[jasti]

@lannka as discussed, this could be optimized further to remove any voluntary delays for 3P ads.

• Instrument current time to create 3P iframe
• Loosen constraint of maximum one ad load per second Unblock next ad load on current ad iframe onload event #9149
• Tweak the constraint of "no ad load in the first 2 seconds of page visible"

[lannka]

I plan to start collecting a new metric to tell us how many times user see blank ad slots.

perceivedAdDelay = Max(adLayoutTime - adFirstInViewportTime, 0);

This value can be significantly affected by the following properties of an ad, so we will want to collect those properties together with the metric.

• if the ad is above the fold or below the fold
• 3 different render flows: 3p, A4A preferential rendering, A4A delayed rendering

@cramforce this is what we talked about.

[lannka]

@cramforce what do you think if we introduce the same thing for non ad elements perceivedContentDelay.

Then our optimization goal becomes: minimize the perceivedAdDelay without increasing the perceivedContentDelay.

[cramforce]

Yes, perfect. Thanks.

[lannka]

The metrics and experiment infrastructure is already set up: #7789. We can start to tweak params and run experiment.

Right now, the voluntary delay is from 2 rules:

1. maximum one ad load per second
2. no ad load in the first 2 seconds of page visible

We can loosen constraint 1), detailed plan here: #9149.
For 2, this is a default setting of AMP resource scheduling. It was introduced as a penalty time for low priority elements:

delayInMs = priority * 1000

@dvoytenko want to hear from you, if you're comfortable that we start tuning this magic number.

[dvoytenko]

It's fine to experiment with this numbers. Let's just make sure we get the right comparison. What numbers (besides perceivedContentDelay) will we look at? I assume "bad frame probability" and perceivedContentDelay[priority < 2]?

[lannka]

@dvoytenko yes, you're right

[ampprojectbot]

This issue hasn't been updated in awhile. @lannka Do you have any updates?

[ampprojectbot]

This issue hasn't been updated in awhile. @lannka Do you have any updates?

[ampprojectbot]

This issue hasn't been updated in awhile. @lannka Do you have any updates?

[lannka]

Closing this as we switched direction to push adoption for fast fetch.