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We have observed a strange behavior while developing for iOS. Creating empty dictionaries results in a huge memory usage, something that does not happen on Windows platforms. For example creating 60000 Guid-float dictionaries result in 30MB memory usage, which is a critical amount on a mobile platform. The same takes up 800kb of memory in a Windows 8.1 Store app.
### Steps to Reproduce:
>Dictionary<Guid, float> dicts = new Dictionary<Guid, float>;
>for (int i = 0; i < 50000; i++)
> dicts[i] = new Dictionary<Guid, float>(0);
It appears that unlike CLR, Mono initializes the dictionary with a size of 12, which results in an additional size of 12*(16+8) per dictionary.
### Actual Results:
~30 MB of memory used on iOS
### Expected Results:
Similar memory profile as shown on Windows (~800 kb)
### Build Date & Platform:
Fixed in master
Mono after 3.6
It still allocates an array with the size of 1. Microsoft's implementation doesn't allocate the array at all:
@Adam: we're now using Microsoft's implementation of Dictionary<T>: https://github.com/mono/mono/commit/346894957c49a9c839236e0fc0296e4e3d44e10b
Oh, you cannot possibly imagine how happy I am to hear that :)
Is it part of MDK 220.127.116.11 (the latest on the alpha channel)? If not, any estimates when this will hit the alpha channel?
It's not in 3.12. I imagine it'll be in 3.14, though I don't have an ETA for that.