[squeak-dev] How immutable data structures can _increase_ application performance

Levente Uzonyi leves at elte.hu
Mon Dec 23 00:43:10 UTC 2013


On Sun, 22 Dec 2013, Frank Shearar wrote:

> http://swannodette.github.io/2013/12/17/the-future-of-javascript-mvcs/
>
> In which David Nolen shows how |UIs built with persistent data
> structures outperform those using mutable state, simply because you
> can check for changes with a simple reference equality check. And you
> get undo for free, and snapshots are trivial. And, because decent
> persistent data structures share structure, it's memory efficient.

According to my benchmarks (and my memory) the immutable binary trees 
(and other non-binary tree structures) I've built were all about 6x slower 
than mutable ones. Spur might make a difference, because the extra cost 
comes mostly from GC. But currently a mutable tree with a semaphore is way 
faster.


Levente

>
> frank
>
>


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