Question

我有一个名为TapApiService的WCF服务，其中包含以下方法：

public class TapApiService : Contracts.ServiceContracts.ITapApiService
{
    private static readonly IConfigurationManagerWrapper ConfigWrapper = new ConfigurationManagerWrapper();
    private static UriManager uriManager = new UriManager(ConfigWrapper.AppSettings["tapScheme"], ConfigWrapper.AppSettings["tapHost"], ConfigWrapper);

    public JobLongForm GetJob(string jobId)
    {
        var request = uriManager.GetUriFromKey("jobResource", jobId).ToString().GetTapRequest("GET", ConfigWrapper);

        return JsonConvert.DeserializeObject<JobLongForm>(request.GetResponseString());
    }

    public IEnumerable<string> GetAllJobIds()
    {
        return GetAllJobs().Select(job => job.Id);
    }

    public IEnumerable<JobShortForm> GetAllJobs()
    {
        var request = uriManager.GetUriFromKey("allJobsResource").ToString().GetTapRequest("GET", ConfigWrapper);

        return JsonConvert.DeserializeObject<JobShortForm[]>(request.GetResponseString());
    }

    public IEnumerable<JobLongForm> GetFullJobs(IEnumerable<string> jobIds)
    {
        return jobIds.Select(GetJob);
    }
}

我有一个我正在测试的控制台应用程序。它具有以下代码： var proxy = new TapApiService（）;

var stopwatch = new Stopwatch();

stopwatch.Start();
var ids = proxy.GetAllJobIds();
proxy.GetFullJobs(ids);
stopwatch.Stop();
Console.WriteLine(stopwatch.GetElapsedTimeString());

stopwatch.Reset();

stopwatch.Start();
proxy.GetAllJobIds().AsParallel().Select(id => proxy.GetJob(id));
stopwatch.Stop();
Console.WriteLine(stopwatch.GetElapsedTimeString());

结果是：00:00:00.713和00:00:00.104 AsParallel()实施显然要快得多。但是，如果我将AsParallel()移动到GetFullJobs(IEnumerable<string> jobIds)方法内部，就像这样：

public IEnumerable<JobLongForm> GetFullJobs(IEnumerable<string> jobIds)
{
    return jobIds.AsParallel().Select(GetJob);
}

我得到00:00:00.813和00:00:00.158。第二个实现仍然更快。我认为他们的表现现在会一样。我在这里缺少什么？

为什么性能与看似相同的代码差异如此之大？

0 个答案: