mcs/class/corlib/ReferenceSources/PlatformHelper.cs

   1 using System.Diagnostics.CodeAnalysis;
   2
   3 namespace System.Threading
   4 {
   5     /// <summary>
   6     /// A helper class to get the number of processors, it updates the numbers of processors every sampling interval.
   7     /// </summary>
   8     internal static class PlatformHelper
   9     {
  10         private const int PROCESSOR_COUNT_REFRESH_INTERVAL_MS = 30000; // How often to refresh the count, in milliseconds.
  11         private static volatile int s_processorCount; // The last count seen.
  12         private static volatile int s_lastProcessorCountRefreshTicks; // The last time we refreshed.
  13
  14         /// <summary>
  15         /// Gets the number of available processors
  16         /// </summary>
  17         [SuppressMessage("Microsoft.Concurrency", "CA8001", Justification = "Reviewed for thread safety")]
  18         internal static int ProcessorCount
  19         {
  20             get
  21             {
  22                 int now = Environment.TickCount;
  23                 int procCount = s_processorCount;
  24                 if (procCount == 0 || (now - s_lastProcessorCountRefreshTicks) >= PROCESSOR_COUNT_REFRESH_INTERVAL_MS)
  25                 {
  26                     s_processorCount = procCount = Environment.ProcessorCount;
  27                     s_lastProcessorCountRefreshTicks = now;
  28                 }
  29
  30                 return procCount;
  31             }
  32         }
  33
  34         /// <summary>
  35         /// Gets whether the current machine has only a single processor.
  36         /// </summary>
  37         internal static bool IsSingleProcessor
  38         {
  39             get { return ProcessorCount == 1; }
  40         }
  41     }
  42 }