PowerShell wrapper fro the GetPerformanceInfo system call

Get-PerformanceInfo.ps1

<# PowerShell wrapper fro the GetPerformanceInfo system call #>
function Get-PerformanceInfo {
    ## Liberally taken from Pinvoke.net, thank you whoever contributed that
    ## http://www.pinvoke.net/default.aspx/psapi/GetPerformanceInfo.html 
    Add-Type -Language CSharp -TypeDefinition @"
using System;
using System.Runtime.InteropServices;
public static class PerformanceInfo
{
    [DllImport("psapi.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool GetPerformanceInfo([Out] out PsApiPerformanceInformation PerformanceInformation, [In] int Size);

    [StructLayout(LayoutKind.Sequential)]
    public struct PsApiPerformanceInformation
    {
        public int Size;
        public IntPtr CommitTotal;
        public IntPtr CommitLimit;
        public IntPtr CommitPeak;
        public IntPtr PhysicalTotal;
        public IntPtr PhysicalAvailable;
        public IntPtr SystemCache;
        public IntPtr KernelTotal;
        public IntPtr KernelPaged;
        public IntPtr KernelNonPaged;
        public IntPtr PageSize;
        public int HandlesCount;
        public int ProcessCount;
        public int ThreadCount;
    }

    public static PerfomanceInfoData GetPerformanceInfo() {
        PerfomanceInfoData data = new PerfomanceInfoData();
        PsApiPerformanceInformation perfInfo = new PsApiPerformanceInformation();
        if (GetPerformanceInfo(out perfInfo, Marshal.SizeOf(perfInfo))) {
            /// data in pages
            data.CommitTotalPages = perfInfo.CommitTotal.ToInt64();
            data.CommitLimitPages = perfInfo.CommitLimit.ToInt64();
            data.CommitPeakPages = perfInfo.CommitPeak.ToInt64();

            /// data in bytes
            Int64 pageSize = perfInfo.PageSize.ToInt64();
            data.PhysicalTotalBytes = perfInfo.PhysicalTotal.ToInt64() * pageSize;
            data.PhysicalAvailableBytes = perfInfo.PhysicalAvailable.ToInt64() * pageSize;
            data.SystemCacheBytes = perfInfo.SystemCache.ToInt64() * pageSize;
            data.KernelTotalBytes = perfInfo.KernelTotal.ToInt64() * pageSize;
            data.KernelPagedBytes = perfInfo.KernelPaged.ToInt64() * pageSize;
            data.KernelNonPagedBytes = perfInfo.KernelNonPaged.ToInt64() * pageSize;
            data.PageSizeBytes = pageSize;

            /// counters
            data.HandlesCount = perfInfo.HandlesCount;
            data.ProcessCount = perfInfo.ProcessCount;
            data.ThreadCount = perfInfo.ThreadCount;
        }
        return data;
    }
}

public class PerfomanceInfoData
{
    public Int64 CommitTotalPages;
    public Int64 CommitLimitPages;
    public Int64 CommitPeakPages;
    public Int64 PhysicalTotalBytes;
    public Int64 PhysicalAvailableBytes;
    public Int64 SystemCacheBytes;
    public Int64 KernelTotalBytes;
    public Int64 KernelPagedBytes;
    public Int64 KernelNonPagedBytes;
    public Int64 PageSizeBytes;
    public int HandlesCount;
    public int ProcessCount;
    public int ThreadCount;
}
"@
    [PerformanceInfo]::GetPerformanceInfo()
}