Try to improve List enumerator perf #116150
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Tagging subscribers to this area: @dotnet/area-system-collections |
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@EgorBot -arm -amd -intel using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;
BenchmarkSwitcher.FromAssembly(typeof(Bench).Assembly).Run(args);
[MemoryDiagnoser(false)]
public class Bench
{
[Benchmark]
[ArgumentsSource(nameof(GetLists))]
public int SumList(List<int> list)
{
int sum = 0;
foreach (int item in list)
{
sum += item;
}
return sum;
}
[Benchmark]
[ArgumentsSource(nameof(GetLists))]
public int SumEnumerable(IEnumerable<int> list)
{
int sum = 0;
foreach (int item in list)
{
sum += item;
}
return sum;
}
public static IEnumerable<List<int>> GetLists() =>
from count in new int[] { 1, 10, 1_000 }
select Enumerable.Range(0, count).ToList();
} |
Member
Author
|
@EgorBot -arm -amd -intel using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;
using System.Runtime.CompilerServices;
BenchmarkSwitcher.FromAssembly(typeof(Bench).Assembly).Run(args);
[DisassemblyDiagnoser]
[MemoryDiagnoser(false)]
public class Bench
{
[Benchmark]
[ArgumentsSource(nameof(GetLists))]
public int SumList(List<string> list)
{
int sum = 0;
foreach (var item in list)
{
sum += Process(item);
}
return sum;
}
[Benchmark]
[ArgumentsSource(nameof(GetLists))]
public int SumEnumerable(IEnumerable<string> list)
{
int sum = 0;
foreach (var item in list)
{
sum += Process(item);
}
return sum;
}
[MethodImpl(MethodImplOptions.NoInlining)]
private static int Process(string item) => item.Length;
public static IEnumerable<List<string>> GetLists() =>
from count in new int[] { 1, 10, 1_000 }
select Enumerable.Range(0, count).Select(i => i.ToString()).ToList();
} |
src/libraries/System.Private.CoreLib/src/System/Collections/Generic/List.cs
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This was referenced May 30, 2025
Member
Author
|
@EgorBot -arm -amd -intel using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;
BenchmarkSwitcher.FromAssembly(typeof(Bench).Assembly).Run(args);
[MemoryDiagnoser(false)]
public class Bench
{
[Benchmark]
[ArgumentsSource(nameof(GetLists))]
public int SumList(List<int> list)
{
int sum = 0;
foreach (int item in list)
{
sum += item;
}
return sum;
}
[Benchmark]
[ArgumentsSource(nameof(GetLists))]
public int SumEnumerable(IEnumerable<int> list)
{
int sum = 0;
foreach (int item in list)
{
sum += item;
}
return sum;
}
public static IEnumerable<List<int>> GetLists() =>
from count in new int[] { 1, 10, 1_000 }
select Enumerable.Range(0, count).ToList();
} |
Member
Author
|
This appears to be a way to achieve the desired goal of helping the boxed case and not negatively impacting the non-boxed case. cc: @EgorBo, @AndyAyersMS |
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