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msgpack / msgpack-javascript

@msgpack/msgpack - MessagePack for JavaScript / msgpack.org[JavaScript/TypeScript/ECMA-262]
https://msgpack.org/
ISC License
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Reuse stack states during decoding to optimize GC load #228

Closed sergeyzenchenko closed 1 year ago

sergeyzenchenko commented 1 year ago

hey @gfx found optimisation that I've missed somehow 2 years ago :D

StackStates are constantly being created for each array or map parsed.

If for example we parse array with 10k objects inside, it will allocate 10001 stack states, but in reality we only need 2 allocations. Max amount of allocation equals the max depth of nested objects/arrays inside on payload.

I've run msgpack benchmark, but it didn't show any large improvements. But I think these tests can't show it because they are very short living and GC have no time to kick off.

Change is simple and can have meaningful impact of apps processing large amount of data.

Also unified stack state object creation with fields from both types created in one place should have impact on V8 optimisation pipeline, because now each object will have the same shape.

gfx commented 1 year ago

It totally makes sense. Thank you.