Open Bug 1667904 Opened 4 years ago Updated 2 years ago

Speculatively parse async and link preload scripts

Categories

(Core :: Performance, enhancement, P2)

Product:
Core
Component:
Performance
Type:
enhancement

Tracking

()

Project Flags:
Performance Impact low

People

(Reporter: denispal, Assigned: denispal)

References

Details

Bug 1606652 did not change the behaviour for async and link preload scripts. Parsing these speculatively often meant they needlessly executed very early and caused regressions since they prevent other important tasks such as painting to occur asap.

Instead, if async script execution can be made as a low priority runnable then we can start parsing these speculatively as well. I also noticed that over 90% of link preload scripts are executed during page load, and often as an async script so they should also be enabled.

Could you set a priority and severity for this as well?

Flags: needinfo?(dpalmeiro)
Severity: -- → N/A
Flags: needinfo?(dpalmeiro)
Priority: -- → P2

Hi Denis, can you please set the expected Performance Impact for this bug?

Flags: needinfo?(dpalmeiro)

When I measured this, it wasn't a big win. The biggest win of Bug 1606652 was moving work off the main thread, and we already do this for async scripts.

Performance Impact: --- → low
Flags: needinfo?(dpalmeiro)
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