如何在短时间内调用大量http请求

我必须每隔几秒钟发送100,000个http请求，并且使用下面提供的代码需要19秒才能发送请求，并且它比我的间隔更长。

在此期间，CPU使用率和以太网使用率为100%。我在双处理器计算机上尝试过，带宽更高，但结果相同。

还有别的方法可以有更好的表现吗?

protected async void btnStartCallWhenAll_Click(object sender, EventArgs e)
{
    t1 = DateTime.Now;
    // Make a list of web addresses. 
    List<string> urlList = SetUpURLList(Convert.ToInt32(txtNoRecordsToAdd.Text));
    // One-step async call. 
    await ProcessAllURLSAsync(urlList);
    t2 = DateTime.Now;
    double spent = t2.Subtract(t1).TotalMilliseconds;
    txtTimeElapsed.Text = " Time Spent :" + spent.ToString() ;
}
private List<string> SetUpURLList(int No)
{
    List<string> urls = new List<string>
    {
    };
    for (int i = 1; i <= No; i++)
        urls.Add("http://msdn.microsoft.com/library/windows/apps/br211380.aspx");
    return urls;
}
private async Task ProcessAllURLSAsync(List<string> urlList)
{
    ServicePointManager.UseNagleAlgorithm = true;
    ServicePointManager.Expect100Continue = true;
    ServicePointManager.CheckCertificateRevocationList = true;
    ServicePointManager.MaxServicePointIdleTime = 10000;
    ServicePointManager.DefaultConnectionLimit = 1000;
    IEnumerable<Task> CallingTasksQuery =
        from url in urlList select CallURLAsync(url);
    Task[] CallingTasks = CallingTasksQuery.ToArray();
    await Task.WhenAll(CallingTasks);
}
private async Task CallURLAsync(string url)
{
    var content = new MemoryStream();
    var webReq = (HttpWebRequest)WebRequest.Create(url);
    using (WebResponse response = await webReq.GetResponseAsync())
    {
    }
}