We need performance tests for preload scanning to improve PreloadScanner.
There was an attempt to improve the performance of preload scanner by running the scanner off-the-main thread. See Bug 63531.
It seems people used html5-parser benchmark. But I think html5-parser is not suitable to measure the performance of preload scanning because this benchmark is intended to measure the parser throughput.
Is it possible to delay the loading of elements in perf tests? For example, I'd like to delay dummy.js loading for 1 second to give enough time for the preload scanner to scan the rest of input stream and request preloads.
It seems web-page-replay used for replay performance tests performs a similar function though the delay is recorded, not manually specified.
I'm not sure how we'd do this?
IMHO, we should just use the PLT to measure this sort of thing. That's really the end-to-end metric that we'd like to move with the preload scanner.