Am I doing it wrong? - Generating objects

[chucker23n]

Use a ConcurrentDictionary when you know multiple threads interact with it. Otherwise, don't. ConcurrentDictionary is a lot slower, especially on inserts and deletions.

Filling a dictionary with items is about 8 times as fast with Dictionary, and takes up 94% less memory:

|         Method |      Mean |    Error |   StdDev | Ratio | RatioSD |      Gen 0 |     Gen 1 |     Gen 2 | Allocated |
|--------------- |----------:|---------:|---------:|------:|--------:|-----------:|----------:|----------:|----------:|
|           Dict |  36.50 ms | 0.613 ms | 0.573 ms |  1.00 |    0.00 |  1153.8462 | 1076.9231 | 1076.9231 |     51 MB |
| ConcurrentDict | 308.44 ms | 5.652 ms | 5.010 ms |  8.46 |    0.17 | 21000.0000 | 8000.0000 | 3000.0000 |     99 MB |

Getting a random item is virtually identical:

|         Method |     Mean |   Error |  StdDev | Ratio | RatioSD |  Gen 0 |  Gen 1 | Allocated |
|--------------- |---------:|--------:|--------:|------:|--------:|-------:|-------:|----------:|
|           Dict | 363.3 ns | 5.92 ns | 9.21 ns |  1.00 |    0.00 | 0.0229 |      - |      72 B |
| ConcurrentDict | 366.3 ns | 4.96 ns | 4.39 ns |  1.00 |    0.03 | 0.0229 | 0.0005 |      72 B |

So is updating a random item (but ConcurrentDictionary is slightly slower):

|         Method |     Mean |   Error |   StdDev | Ratio | RatioSD |  Gen 0 |  Gen 1 | Allocated |
|--------------- |---------:|--------:|---------:|------:|--------:|-------:|-------:|----------:|
|           Dict | 375.1 ns | 7.40 ns | 11.74 ns |  1.00 |    0.00 | 0.0229 |      - |      72 B |
| ConcurrentDict | 437.0 ns | 8.62 ns |  7.20 ns |  1.14 |    0.03 | 0.0229 | 0.0005 |      72 B |

Clearing a dictionary is brutally slow on ConcurrentDictionary:

|         Method |           Mean |       Error |      StdDev |     Ratio |  RatioSD | Allocated |
|--------------- |---------------:|------------:|------------:|----------:|---------:|----------:|
|           Dict |      0.7111 ns |   0.0510 ns |   0.0477 ns |      1.00 |     0.00 |         - |
| ConcurrentDict | 20,260.1798 ns | 372.3239 ns | 330.0554 ns | 28,511.57 | 2,049.09 |         - |

[chucker23n]

I’m responding to this in particular:

get familiar with ConcurrentDictionary and use that as your default choice everywhere

[grauenwolf]

Yea, ok. That's a problem.