[shunia_huang]

I've been long on JS but never heard things like this, could you please prove it by any means or at least give a valid proof to the _around 15%_ statement? Also by saying _quick enough to not be noticeable_, what's the situation you are referring too? I thought the GC overhead will stack until it eventually affects the UI responsiveness when handling continues IO or rendering loads, as recently I have done some perf stuff for such cases and optimizing count of objects did make things better and the console definitely showed some GC improvements, you make me nerve to go back and check again.

[conartist6]

Yeah I mean don't take my word, play around with it! Here's a simple JSFiddle that makes an iterator of 10,000,000 items, each with a step object that cannot be optimized except through efficient minor GC. Try using your browser's profiler to look at the costs of running it! My profiler says 40% of the time is spent inside `next()` and only 1% of the time is spent on minor GCs. (I used the Firefox profiler. Chrome was being weird and not showing me any data from inside the fiddle iframe).

[shunia_huang]

To me this is just "fake test". As I have said really world cases involves consistent IO loads and/or rendering loops, for example in my case I need to load tons of pixel data and decode them in works, then at the same time use canvas to render the decoded image and huge chunk of array data, they are real world high loads, there are tons of objects created during the process and way less counts than the "fake test", yet still optimizing the object counts made huge difference to the final performance.

Let's say talk about this in another more general case: virtual windowing. If anyone has tried to implement stuff and hit performance bottle neck and then find virtual windowing could help, it definitely involves two problems to solve, first is the UI responsiveness when more and more stuff got created and rendered, the object count usually should be way less than "10,000,000", yet still you could hit the wall.

I think I might be too negative about it, but I just want to share the real cases here.

[vlovich123]

JSFiddle link missing.

[conartist6]

sry https://jsfiddle.net/L10dw6gn/3/