Prefetch via Compositor Link Hit Testing

[Timothy Dresser]

I've jotted down an idea I had on reducing page load time by hit testing URLs on the compositor thread, and using this information to aggressively prefetch the main resource.

Doc here.

This would likely be high impact for low end devices, and measuring the potential impact should be fairly straight forward.

The complexity of the implementation depends on how clean our slimming paint v2 hit testing logic is.

Tim

[Ojan Vafai]

I'm biased, but measuring the potential impact seems worth it to me. Whether it's worth the complexity will obviously depend on those numbers.

[Kinuko Yasuda]

Thanks Tim for following up this-- Made some comments on the doc.  In general I'm a bit concerned about the overhead and privacy leaking aspect of aggressive prefetch, while I agree that measuring something would be still useful if doing so wouldn't add much complexity.

[Kenji Baheux]

Just to add: +1 on measuring the opportunity especially if it's relatively cheap to do implement a metric.

We can discuss the value vs. cost (implementation, time spent in LR process, etc.) later.