Open Bug 1811541 Opened 2 years ago Updated 1 year ago

JS demo (https://www.fxhash.xyz/generative/19682) takes 30 seconds to load on Nightly, Chrome takes 8 seconds

Categories

(Core :: JavaScript Engine: JIT, defect, P3)

Product:
Core
Component:
JavaScript Engine: JIT
Type:
defect

Tracking

()

People

(Reporter: mayankleoboy1, Unassigned)

References

(Depends on 1 open bug, Blocks 1 open bug)

Details

If you are on Windows, disable d2d (else the demo is dominated by gfx stuff).
go to https://www.fxhash.xyz/generative/19682
Click on the "open" button

Nightly: https://share.firefox.dev/3IZxpYV
Chrome: https://share.firefox.dev/3R9lpGp

Summary: JS demo (https://www.fxhash.xyz/generative/19682) takes 60 seconds to run on Nightly, Chrome takes 8 seconds → JS demo (https://www.fxhash.xyz/generative/19682) takes 60 seconds to load on Nightly, Chrome takes 8 seconds

this may be something to do with Private fields..

Most of the time seems to be spend parsing functions using the Function constructor.

(In reply to Tom S [:evilpie] from comment #2)

Most of the time seems to be spend parsing functions using the Function constructor.

Yeah, this might be bug 1420440. If we're passing the same string to this constructor, V8 can use the eval cache.

Depends on: 1420440
Severity: -- → S3
Priority: -- → P3

Surprisingly, Bug 1817640 - extract calculation of max dirty value to a helper method EffectiveMaxDirty(), r=pbone improved this testcase from 45seconds->30seconds.

Depends on: 1817640
Summary: JS demo (https://www.fxhash.xyz/generative/19682) takes 60 seconds to load on Nightly, Chrome takes 8 seconds → JS demo (https://www.fxhash.xyz/generative/19682) takes 30 seconds to load on Nightly, Chrome takes 8 seconds

Enabling the profiler on this testcase adds ~50% overhead, which seems excessive.

Without profiler: 28s
With profiler: 42s https://share.firefox.dev/3GLEs56

Edit: Filed bug 1870428

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