Fix LLC cache issue on Apple M1

[EgorBo]

Addresses the L3 cache issue we've found in #60166 but for macOS-arm64

It seems that since macOS 12.0, Apple added more entries for sysctl (see #62832 (comment)). And it turns out the keys we were using report cache size for the "efficiency cores", not the performance ones. As the result, PAL_GetLogicalProcessorCacheSizeFromOS used to return 4mb instead of expected 12mb.

This change shows nice improvements for GC-bound benchmarks and should address #60616 (comment)

using System;
using System.Runtime.CompilerServices;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

public class Test
{
    public static void Main(string[] args) => 
        BenchmarkSwitcher.FromAssembly(typeof(Test).Assembly).Run(args);

    [Benchmark]
    [Arguments(10000)]
    [Arguments(128)]
    public char[] AllocateUninit(int len) => GC.AllocateUninitializedArray<char>(len);

    [Benchmark]
    [Arguments(2000)]
    [Arguments(256)]
    public char[] AllocateArray(int len) => new char[len];
    
    [Benchmark]
    public object SmallAllocation() => new object[] { new(), new() };

    [Benchmark]
    public string IntToString() => 42.ToString();
}

Results (Apple M1 mac mini):

Method	Toolchain	len	Mean	Error	StdDev	Ratio
SmallAllocation	/Core_Root/corerun	?	12.695 ns	0.0422 ns	0.0352 ns	1.10
SmallAllocation	/Core_Root_PR/corerun	?	11.534 ns	0.0453 ns	0.0423 ns	1.00
IntToString	/Core_Root/corerun	?	6.239 ns	0.0058 ns	0.0052 ns	1.08
IntToString	/Core_Root_PR/corerun	?	5.782 ns	0.0074 ns	0.0069 ns	1.00
AllocateUninit	/Core_Root/corerun	128	14.195 ns	0.1914 ns	0.1790 ns	1.43
AllocateUninit	/Core_Root_PR/corerun	128	9.952 ns	0.0622 ns	0.0582 ns	1.00
AllocateArray	/Core_Root/corerun	256	26.071 ns	0.3068 ns	0.2562 ns	1.46
AllocateArray	/Core_Root_PR/corerun	256	17.843 ns	0.1272 ns	0.1190 ns	1.00
AllocateArray	/Core_Root/corerun	2000	180.445 ns	3.6465 ns	3.4110 ns	1.66
AllocateArray	/Core_Root_PR/corerun	2000	108.966 ns	0.9273 ns	0.8674 ns	1.00
AllocateUninit	/Core_Root/corerun	10000	529.512 ns	3.2077 ns	3.0005 ns	2.51
AllocateUninit	/Core_Root_PR/corerun	10000	211.415 ns	3.5344 ns	3.3060 ns	1.00

[EgorBo]

Unrelated to this PR, when I play with DOTNET_GCgen0size with bigger values I get even better results for these benchmarks.

[EgorBo]

cc @dotnet/gc @janvorli

[EgorBo]

Btw, here is what sysctrl -a reports on my M1: https://gist.github.com/EgorBo/df63dfe24f5463009fbf2490e406b39c

[janvorli]

Thanks @EgorBo for sharing the output of the sysctrl -a! There is much more interesting information than I expected.

[janvorli]

LGTM, thank you!