问如何在单线程应用程序中使用FileStream提高吞吐量

EN

   volatile bool _somethingLeftToRead = false;
   long _totalReadInSize = 0;
   void ProcessReadThread(object obj)
   {
      TestThreadJob job = obj as TestThreadJob;
      var dirInfo = new DirectoryInfo(job.InFilePath);
      int chunk = job.DataBatchSize * 1024;

      //var tile = new List<byte[]>();

      var sw = new Stopwatch();

      var allFiles = dirInfo.GetFiles();

      var fileStreams = new List<FileStream>();
      long totalSize = 0;
      _totalReadInSize = 0;

      foreach (var fileInfo in allFiles)
      {
         totalSize += fileInfo.Length;
         var fileStream = new FileStream(fileInfo.FullName,
             FileMode.Open, FileAccess.Read, FileShare.None, job.FileBufferSize * 1024);

         fileStreams.Add(fileStream);
      }

      var partial = new byte[chunk];
      var taskParam = new TaskParam(null, partial);
      var tasks = new List<Task>();
      int numTasks = (int)Math.Ceiling(fileStreams.Count * 1.0 / job.NumThreads);
      sw.Start();

      do
      {
         _somethingLeftToRead = false;

         for (int taskIndex = 0; taskIndex < numTasks; taskIndex++)
         {
            if (_threadCanceled)
               break;
            tasks.Clear();
            for (int thread = 0; thread < job.NumThreads; thread++)
            {
               if (_threadCanceled)
                  break;
               int fileIndex = taskIndex * job.NumThreads + thread;
               if (fileIndex >= fileStreams.Count)
                  break;
               var fileStream = fileStreams[fileIndex];

               taskParam.File = fileStream;
               if (job.NumThreads == 1)
                  ProcessFileRead(taskParam);
               else
                  tasks.Add(Task.Factory.StartNew(ProcessFileRead, taskParam));

               //tile.Add(partial);
            }
            if (_threadCanceled)
               break;
            if (job.NumThreads > 1)
               Task.WaitAll(tasks.ToArray());
         }

         //tile = new List<byte[]>();
      }
      while (_somethingLeftToRead);

      sw.Stop();

      foreach (var fileStream in fileStreams)
         fileStream.Close();

      totalSize = (long)Math.Round(totalSize / 1024.0 / 1024.0);
      UpdateUIRead(false, totalSize, sw.Elapsed.TotalSeconds);
   }

   void ProcessFileRead(object taskParam)
   {
      TaskParam param = taskParam as TaskParam;
      int readInSize;
      if ((readInSize = param.File.Read(param.Bytes, 0, param.Bytes.Length)) != 0)
      {
         _somethingLeftToRead = true;
         _totalReadInSize += readInSize;
      }
   }