Util/IoPriority.cs

   1 //
   2 // IoPriority.cs
   3 //
   4 // Copyright (C) 2005 Novell, Inc.
   5 //
   6
   7 //
   8 // Permission is hereby granted, free of charge, to any person obtaining a
   9 // copy of this software and associated documentation files (the "Software"),
  10 // to deal in the Software without restriction, including without limitation
  11 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
  12 // and/or sell copies of the Software, and to permit persons to whom the
  13 // Software is furnished to do so, subject to the following conditions:
  14 //
  15 // The above copyright notice and this permission notice shall be included in
  16 // all copies or substantial portions of the Software.
  17 //
  18 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  24 // DEALINGS IN THE SOFTWARE.
  25 //
  26
  27 using System;
  28 using System.Runtime.InteropServices;
  29
  30 namespace Beagle.Util {
  31
  32         public class IoPriority {
  33
  34                 private IoPriority () {} // Static class
  35
  36                 [DllImport ("libbeagleglue")]
  37                 static extern int set_io_priority_idle ();
  38
  39                 [DllImport ("libbeagleglue")]
  40                 static extern int set_io_priority_best_effort (int ioprio);
  41
  42                 static public void ReduceIoPriority ()
  43                 {
  44                         // First try setting our IO class to idle, so that we
  45                         // only ever get run if there are no other IO tasks.
  46                         // If that fails, then try setting our IO priority
  47                         // within the best effort class to the lowest we can,
  48                         // which is priority 7.
  49
  50                         if (set_io_priority_idle () >= 0)
  51                                 Log.Debug ("Set IO priority class to idle.");
  52                         else if (set_io_priority_best_effort (7) >= 0)
  53                                 Log.Debug ("Set best effort IO priority to lowest level (7)");
  54                         else
  55                                 Log.Warn ("Unable to set IO priority class to idle or IO priority within best effort class to 7");
  56                 }
  57         }
  58 }