Force Normal IO and Page Priority

More useful when run as Task but it seems to help normal
runs as well. Related to issue #487.

DS4Windows/DS4Control/Util.cs

@@ -0,0 +1,67 @@
+using System;
+using System.Runtime.InteropServices;
+using System.Security;
+using System.Text;
+
+namespace DS4Windows
+{
+    [SuppressUnmanagedCodeSecurity]
+    class Util
+    {
+        public enum PROCESS_INFORMATION_CLASS : int
+        {
+            ProcessBasicInformation = 0,
+            ProcessQuotaLimits,
+            ProcessIoCounters,
+            ProcessVmCounters,
+            ProcessTimes,
+            ProcessBasePriority,
+            ProcessRaisePriority,
+            ProcessDebugPort,
+            ProcessExceptionPort,
+            ProcessAccessToken,
+            ProcessLdtInformation,
+            ProcessLdtSize,
+            ProcessDefaultHardErrorMode,
+            ProcessIoPortHandlers,
+            ProcessPooledUsageAndLimits,
+            ProcessWorkingSetWatch,
+            ProcessUserModeIOPL,
+            ProcessEnableAlignmentFaultFixup,
+            ProcessPriorityClass,
+            ProcessWx86Information,
+            ProcessHandleCount,
+            ProcessAffinityMask,
+            ProcessPriorityBoost,
+            ProcessDeviceMap,
+            ProcessSessionInformation,
+            ProcessForegroundInformation,
+            ProcessWow64Information,
+            ProcessImageFileName,
+            ProcessLUIDDeviceMapsEnabled,
+            ProcessBreakOnTermination,
+            ProcessDebugObjectHandle,
+            ProcessDebugFlags,
+            ProcessHandleTracing,
+            ProcessIoPriority,
+            ProcessExecuteFlags,
+            ProcessResourceManagement,
+            ProcessCookie,
+            ProcessImageInformation,
+            ProcessCycleTime,
+            ProcessPagePriority,
+            ProcessInstrumentationCallback,
+            ProcessThreadStackAllocation,
+            ProcessWorkingSetWatchEx,
+            ProcessImageFileNameWin32,
+            ProcessImageFileMapping,
+            ProcessAffinityUpdateMode,
+            ProcessMemoryAllocationMode,
+            MaxProcessInfoClass
+        }
+
+        [DllImport("ntdll.dll", SetLastError = true)]
+        public static extern int NtSetInformationProcess(IntPtr processHandle,
+           PROCESS_INFORMATION_CLASS processInformationClass, ref IntPtr processInformation, uint processInformationLength);
+    }
+}

DS4Windows/DS4Windows.csproj

@@ -141,6 +141,7 @@
     <Compile Include="DS4Control\ScpDevice.cs" />
     <Compile Include="DS4Control\ScpUtil.cs" />
     <Compile Include="DS4Control\UdpServer.cs" />
+    <Compile Include="DS4Control\Util.cs" />
     <Compile Include="DS4Control\X360Device.cs" />
     <Compile Include="DS4Forms\LanguagePackComboBox.cs">
       <SubType>UserControl</SubType>

DS4Windows/Program.cs

@@ -75,6 +75,16 @@ namespace DS4Windows
             }
             catch { } // Ignore problems raising the priority.
 
+            // Force Normal IO Priority
+            IntPtr ioPrio = new IntPtr(2);
+            Util.NtSetInformationProcess(Process.GetCurrentProcess().Handle,
+                Util.PROCESS_INFORMATION_CLASS.ProcessIoPriority, ref ioPrio, 4);
+
+            // Force Normal Page Priority
+            IntPtr pagePrio = new IntPtr(5);
+            Util.NtSetInformationProcess(Process.GetCurrentProcess().Handle,
+                Util.PROCESS_INFORMATION_CLASS.ProcessPagePriority, ref pagePrio, 4);
+
             try
             {
                 // another instance is already running if OpenExsting succeeds.