CODEWITHSUNDEEP
javascriptoptimizationbrowserdata-structures
OttoRobba
OttoRobba

Reputation: 83

Does data locality matter in JavaScript?

I'm a game developer and I have been trying different structures to see what would give me the best results but it seems that JavaScript is mostly unaffected by data locality, meaning that processing times are within margin of error and memory usage is mostly as expected.

Does data locality matter at all in JavaScript or am I just wasting my time trying to improve certain structures?

Is it due to the sandboxed nature of the execution environment (i.e. it would matter outside the browser)?

Upvotes: 3

Views: 1254

Answers (1)

KECG
KECG

Reputation: 106

This article is an interesting read. It says, in summary, low level locality optimizations are a lost cause, but big data structures, big arrays of data structures more so, should be accessed in linear order.

Coming from a C background, I tend to access a grid held in a 1D array in a Y-outer/X-inner pattern anyway, but when I have done otherwise, I can tell you from experience, it starts to lag on large grids.

So, to attempt to answer your question, and in part theorize: to the degree that this holds true, the classic structure-of-arrays rather than array-of-structures mentality might very well be performant for sufficiently large arrays of large structures with limited variable access in a given case. But I would definitely test both macro-structures if I were implementing a critical feature :)

Upvotes: 1

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