2

我有兴趣将我的函数调用计时到数据库 + 其他函数，以便为我的应用程序性能构建一些指标。我使用了 Stopwatch 和一个指标对象，但它似乎并不能始终如一地给出正确的值。有时调用函数的时间对于所有调用都是完全相同的，这是不现实的......

我发现问题的原因是由于 Metrics 对象属性值。当其他线程生成的 Metrics 的其他实例被赋值时，一个 Metrics 对象的值将被覆盖。尽管每个线程都创建了一个新实例，但属性值似乎是每个引用。

在多个线程共享的对象中实现唯一性的最佳方法是什么？

下面的代码：

private Metrics Metrics;
private Stopwatch Stopwatch;
private int DegreeOfParallelism { get { return Convert.ToInt32(ConfigurationManager.AppSettings["DegreeOfParallelism"].ToString()); } }

var lOptions = new ParallelOptions() { MaxDegreeOfParallelism = DegreeOfParallelism };
Parallel.ForEach(RequestBag, lOptions, (lItem, loopState) =>
{
    if (!string.IsNullOrEmpty(lItem.XmlRequest))
    {
        try
        {
            Metrics = new Metrics();
            Stopwatch = new Stopwatch();
            Stopwatch.Start();
            ObjRef = new Object();
            lItem.XmlRequest = ObjRef.GetDecision(Username, Password);
            Stopwatch.Stop();
            Metrics.ElapsedTime = string.Format("{0:0.00}", Stopwatch.Elapsed.TotalSeconds);

            Stopwatch.Restart();
            if (!string.IsNullOrEmpty(DBConnectionString))
            {
                DataAccess = new DataAccess2(DBConnectionString);
                DataAccess.WriteToDB(lItem.XmlRequest);  
            }
            Stopwatch.Stop();
            Metrics.DbFuncCallTime = string.Format("{0:0.00}", Stopwatch.Elapsed.TotalSeconds); 
        }
        catch (Exception pEx)
        { 
            KeepLog(pEx);
            Metrics.HasFailed = true;
        }
        finally
        {
            ProcessedIdsBag.Add(lItem.OrderId);
            Metrics.ProcessedOrderId = lItem.OrderId;
            Metrics.DegreeOfParallelism = DegreeOfParallelism;
            Metrics.TotalNumOfOrders = NumberOfOrders;
            Metrics.TotalNumOfOrdersProcessed = ProcessedIdsBag.Count;
            pBackgroundWorker.ReportProgress(Metrics.GetProgressPercentage(NumberOfOrders, ProcessedIdsBag.Count), Metrics);

            RequestBag.TryTake(out lItem);
        }
    }
});

任何帮助将不胜感激。谢谢，R

4

2 回答 2

1

您似乎想要做的是为每次迭代创建一个指标对象，然后在最后聚合它们：

private ConcurrentBag<Metrics> allMetrics = new ConcurrentBag<Metrics>();
private int DegreeOfParallelism { get { return Convert.ToInt32(ConfigurationManager.AppSettings["DegreeOfParallelism"].ToString()); } }

var lOptions = new ParallelOptions() { MaxDegreeOfParallelism = DegreeOfParallelism };
Parallel.ForEach(RequestBag, lOptions, (lItem, loopState) =>
{
    if (!string.IsNullOrEmpty(lItem.XmlRequest))
    {
        try
        {
            var Metrics = new Metrics();
            var Stopwatch = new Stopwatch();
            Stopwatch.Start();
            ObjRef = new Object();
            lItem.XmlRequest = ObjRef.GetDecision(Username, Password);
            Stopwatch.Stop();
            Metrics.ElapsedTime = string.Format("{0:0.00}", Stopwatch.Elapsed.TotalSeconds);

            Stopwatch.Restart();
            if (!string.IsNullOrEmpty(DBConnectionString))
            {
                DataAccess = new DataAccess2(DBConnectionString);
                DataAccess.WriteToDB(lItem.XmlRequest);  
            }
            Stopwatch.Stop();
            Metrics.DbFuncCallTime = string.Format("{0:0.00}", Stopwatch.Elapsed.TotalSeconds); 
        }
        catch (Exception pEx)
        { 
            KeepLog(pEx);
            Metrics.HasFailed = true;
        }
        finally
        {
            ProcessedIdsBag.Add(lItem.OrderId);
            Metrics.ProcessedOrderId = lItem.OrderId;
            Metrics.DegreeOfParallelism = DegreeOfParallelism;
            Metrics.TotalNumOfOrders = NumberOfOrders;
            Metrics.TotalNumOfOrdersProcessed = ProcessedIdsBag.Count;
            pBackgroundWorker.ReportProgress(Metrics.GetProgressPercentage(NumberOfOrders, ProcessedIdsBag.Count), Metrics);

            RequestBag.TryTake(out lItem);
            allMetrics.add(Metrics);
        }
    }
});

// Aggregate everything in AllMetrics here
于 2012-01-27T15:52:03.687 回答
1

您需要更改 Stopwatch 和 Metrics 变量的范围。

目前，每个线程共享相同的 Metrics 变量。一旦线程进入 try 块，它就会创建一个新的 Metrics 实例（正确），但将其放入共享变量（错误）。所有其他线程将在读取共享变量时看到该新实例，直到下一个线程出现并重新开始整个过程​​。

移动

private Metrics Metrics;
private Stopwatch Stopwatch;

就在你的循环内

Parallel.ForEach(RequestBag, lOptions, (lItem, loopState) =>
{
    private Metrics Metrics;
    private Stopwatch Stopwatch;
...

这将通过循环为每次迭代提供它自己的变量，在该变量中存储它自己的对象实例。

于 2012-01-30T18:25:06.157 回答