Windows PsApi GetPerformanceInfo C# Wrapper

Here is a wrapper for Windows PsApi function GetPerformanceInfo, with it you can get information about memory, process count, handles count etc.

Usage sample :

PerfomanceInfoData perfData = PsApiWrapper.GetPerformanceInfo();
Console.Write("Available memory: " + perfData.PhysicalAvailableBytes.ToString());
Console.Write("Total memory: " + perfData.PhysicalTotalBytes.ToString());

Here is the code :

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;

public static class PsApiWrapper
  [DllImport("psapi.dll", SetLastError = true)]
  [return: MarshalAs(UnmanagedType.Bool)]
  private static extern bool GetPerformanceInfo([Out] out PsApiPerformanceInformation PerformanceInformation, [In] int Size);

  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;