نکته پرفورمنسی در مورد List

var list = new List<char>();   // []   Count:    0  Capacity: 0

list.Add('h');                 // ['h', null, null, null] 	Count: 1	Capacity: 4

list.Add('e');                 // ['h', 'e', null, null] 	Count: 2	Capacity: 4

list.Add('l');                 // ['h', 'e', 'l', null]     Count: 3	Capacity: 4
 
list.Add('l');                 // ['h', 'e', 'l', 'l']   	Count: 4	Capacity: 4  

list.Add('o');                 // ['h', 'e', 'l', 'l', 'o' , null, null, null]   Count:5	Capacity: 8

list.Add(' ');                 // ['h', 'e', 'l', 'l', 'o' , ' ', null, null]    Count:6	Capacity: 8

list.Add('w');                 // ['h', 'e', 'l', 'l', 'o' , ' ', 'w', null]     Count:7	Capacity: 8

list.Add('o');                 // ['h', 'e', 'l', 'l', 'o' , ' ', 'w', 'o']      Count:8	Capacity: 8

list.Add('r');                 // ['h', 'e', 'l', 'l', 'o' , ' ', 'w', 'o', 'r', null, null, null, null, null, null, null]   Count: 9	Capacity: 16

list.Add('l');                 // ['h', 'e', 'l', 'l', 'o' , ' ', 'w', 'o', 'r', 'l', null, null, null, null, null, null]    Count: 10	Capacity: 16

list.Add('d');                 // ['h', 'e', 'l', 'l', 'o' , ' ', 'w', 'o', 'r', 'l', 'd', null, null, null, null, null]     Count: 11	Capacity: 16

var list = new List<char>(11);

List<int> numbers = new List<int>();
numbers.Add(5);
numbers.Add(1);
numbers.Add(3);
numbers.Add(2);
numbers.Add(0);
Console.WriteLine(numbers.Capacity);
numbers.Clear();
Console.WriteLine(numbers.Capacity);
numbers.TrimExcess();
Console.WriteLine(numbers.Capacity);

8
8
0

[MemoryDiagnoser]
public class ListMemoryAllocationTest
{
    public int Count { get; set; } = 100000;
    [Benchmark]
    public  void DefaultConstructor()
    {
        List<int> numbers = new List<int>();
        for (int i = 0; i < Count; i++)
        {
            numbers.Add(i);
        }
    }
    [Benchmark]
    public  void AddCountToConstructor()
    {
        List<int> numbers = new List<int>(Count);
        for (int i = 0; i < Count; i++)
        {
            numbers.Add(i);
        }
    }
}
public class Program
{
    public static void Main()
    {
        BenchmarkRunner.Run<ListMemoryAllocationTest>();
    }
}

|                Method |     Mean |    Error |   StdDev |    Gen 0 |    Gen 1 |    Gen 2 | Allocated |

|    DefaultConstructor | 753.4 us | 14.80 us | 15.20 us | 628.9063 | 627.9297 | 237.3047 |  1,024 KB |
| AddCountToConstructor | 499.6 us |  9.86 us | 17.78 us | 255.8594 | 255.8594 |  95.7031 |    391 KB |