List Add is way slower (almost 3 times) in `net9.0 preview 3` than with `net8.0`

[linkdotnet]

With the latest preview 3 (net9) there seems to be a major performance regression on MacOS 14.4 (M2 Pro) with lists. Given that they are one of the most used types, it should receive special treatment.

Benchmark

[Benchmark]
public List<int> ListAdd10000()
{
    var list = new List<int>();
    for (var i = 0; i < 10_000; i++)
    {
        list.Add(i);
    }

    return list;
}

[Benchmark]
public List<int> ListAdd10000PreAlloc()
{
    var list = new List<int>(10_000);
    for (var i = 0; i < 10_000; i++)
    {
        list.Add(i);
    }

    return list;
}

Results:

BenchmarkDotNet v0.13.12, macOS Sonoma 14.4.1 (23E224) [Darwin 23.4.0]
Apple M2 Pro, 1 CPU, 12 logical and 12 physical cores
.NET SDK 9.0.100-preview.3.24204.13
  [Host]   : .NET 9.0.0 (9.0.24.17209), Arm64 RyuJIT AdvSIMD
  .NET 8.0 : .NET 8.0.2 (8.0.224.6711), Arm64 RyuJIT AdvSIMD
  .NET 9.0 : .NET 9.0.0 (9.0.24.17209), Arm64 RyuJIT AdvSIMD

| Method               | Runtime  | Mean      | Error     | StdDev    | Ratio | 
|--------------------- |--------- |----------:|----------:|----------:|------:|-
| ListAdd10000         | .NET 8.0 |  9.739 us | 0.0236 us | 0.0209 us |  1.00 | 
| ListAdd10000         | .NET 9.0 | 25.646 us | 0.1531 us | 0.1432 us |  2.63 | 
|                      |          |           |           |           |       | 
| ListAdd10000PreAlloc | .NET 8.0 |  6.701 us | 0.0175 us | 0.0146 us |  1.00 | 
| ListAdd10000PreAlloc | .NET 9.0 | 22.562 us | 0.1429 us | 0.1336 us |  3.37 |

Interestingly even the pre-allocated list is comparably slow.

dotnet --info

Output

dotnet --info .NET SDK: Version: 9.0.100-preview.3.24204.13 Commit: 81f61d8290 Workload version: 9.0.100-manifests.77bb7ba9 MSBuild version: 17.11.0-preview-24178-16+7ca3c98fa Runtime Environment: OS Name: Mac OS X OS Version: 14.4 OS Platform: Darwin RID: osx-arm64 Base Path: /usr/local/share/dotnet/sdk/9.0.100-preview.3.24204.13/ .NET workloads installed: There are no installed workloads to display. Host: Version: 9.0.0-preview.3.24172.9 Architecture: arm64 Commit: 9e6ba1f68c .NET SDKs installed: 6.0.417 [/usr/local/share/dotnet/sdk] 7.0.306 [/usr/local/share/dotnet/sdk] 7.0.404 [/usr/local/share/dotnet/sdk] 8.0.100 [/usr/local/share/dotnet/sdk] 8.0.101 [/usr/local/share/dotnet/sdk] 8.0.200 [/usr/local/share/dotnet/sdk] 9.0.100-preview.2.24121.2 [/usr/local/share/dotnet/sdk] 9.0.100-preview.2.24157.14 [/usr/local/share/dotnet/sdk] 9.0.100-preview.3.24204.13 [/usr/local/share/dotnet/sdk] .NET runtimes installed: Microsoft.AspNetCore.App 6.0.25 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 7.0.14 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 8.0.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 8.0.1 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 8.0.2 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 9.0.0-preview.2.24120.6 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 9.0.0-preview.2.24128.4 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App] Microsoft.AspNetCore.App 9.0.0-preview.3.24172.13 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App] Microsoft.NETCore.App 6.0.25 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App] Microsoft.NETCore.App 7.0.14 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App] Microsoft.NETCore.App 8.0.0 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App] Microsoft.NETCore.App 8.0.1 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App] Microsoft.NETCore.App 8.0.2 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App] Microsoft.NETCore.App 9.0.0-preview.2.24120.11 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App] Microsoft.NETCore.App 9.0.0-preview.2.24128.5 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App] Microsoft.NETCore.App 9.0.0-preview.3.24172.9 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App] Other architectures found: x64 [/usr/local/share/dotnet/x64] Environment variables: Not set global.json file: Not found Learn more: https://aka.ms/dotnet/info Download .NET: https://aka.ms/dotnet/download