Question

我有azure A4基本机器（8芯）来测试我的应用程序：

namespace DownloadSomeData 
{
   internal class FileDownloader
   {
    int nextIndex = 0;
    int _ListSize;
    readonly uint MaxConcurrentDownloads = 0;
    private IList<MyModel> _ValidList;

    public FileDownloader(uint maxConcurrentThread, IList<MyModel> list)
    {
        _ValidList = list;
        MaxConcurrentDownloads = maxConcurrentThread;
        //Get the items count
        _ListSize = _ValidList.Count();

    }
    /// <summary>
    /// 
    /// </summary>
    public async Task Start()
    {
        uint parallelThreads = MaxConcurrentDownloads;

        if (_ListSize < MaxConcurrentDownloads)
        {
            parallelThreads = (uint)_ListSize;
        }
        // Now, start the downloads.
        for (int i = 0; i < parallelThreads; ++i)
        {
            var client = GetNextWebClient();
            MyModel nextObject = _ValidList.ElementAt(i);
            StartDownload(client, nextObject);
            nextIndex++;
        }

    }

    private WebClient GetNextWebClient()
    {
        var client = new WebClient();
        client.DownloadProgressChanged += DownloadProgressChanged;
        client.DownloadFileCompleted += DownloadFileCompleted;
        return client;
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="client"></param>
    private void StartDownload(WebClient client, MyModel state)
    {
        try
        {
            string fname = state.ImageFilename;
            state.DownloadStatus = EnumDownloadStatus.Started;
            client.DownloadFileAsync(new Uri(state.ImageUri), fname, state);  // start the asynchronous download.
        }
        finally
        {
            if (client != null)
            {
                client.Dispose();
            }
        }

    }



    /// <summary>
    /// 
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
    {
    // Progress tracking here
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void DownloadFileCompleted(object sender, AsyncCompletedEventArgs e)
    {
        var model = (MyModel)e.UserState;
        if (e.Error != null)
        {
        }
        else if (e.Cancelled == true)
        {

        }
        else
        {
        }
        var index = nextIndex;
        if (index < _ListSize)
        {
            MyModel nextObject = _ValidList.ElementAt(index);
            nextIndex = nextIndex + 1;
            StartDownload(GetNextWebClient(), nextObject);
        }
    }
}}

此代码始终执行2或最多3个并行文件下载。即使在i5（4核）机器上我也有同样的行为。实际上我在i5机器上运行了一些其他应用程序。但除此之外，azure机器没有其他程序在运行。

我使用以下方法调用此代码：

    private async Task StartDownload
    {
        FileDownloader download = new FileDownloader(_ConcurrentThread, _List);
        await download.Start();
    }

我是否编写了写入逻辑以将最大内核用于应用程序？

文件在8核CPU上下载异步

0 个答案: