点网：在Express Edition Visual Studio 2008中线程运行太慢吗？

Question

i am running 12 threads .function which these threads are calling is not having any lock on some object.but still these threads are taking too much time.(16 minutes).each thread ially parsing a xml document which is running alright if run indiviually.is this problem because of some reason related max no threads provided by express edition or some blocking dn by express edition.

---

code of func whic each thread calls is given below. each thread is given different rssfeed(urladdress)

public static class RssFileReader
{
    public static Rss GetRssDocumentData(string rssFeed)
    {
        Console.WriteLine("thread in RssFileReader: " + Thread.CurrentThread.Name);

        IFormatProvider culture = new CultureInfo("fr-FR", true);

        Rss rssDocumentObject=new Rss();
        XmlDocument documentObj = new XmlDocument();
        try
        {
            documentObj.Load(HttpClient.GetWebResponse(@rssFeed, null, null, 1200000, @"http://www.sahil.com").GetResponseStream());
        }
        catch(Exception e)
        {
            e.Source = "RssFileReader:Loading xmldocument object";
            throw;
        }
        try
        {
            XmlNodeList channelList = documentObj.GetElementsByTagName("channel");
            for (int k = 0; k < channelList.Count; k++)
            {

                rssDocumentObject.ListOfChannel.Add(new Channel());
                int noOfItemInChannel = -1;
                //XmlNodeList itemList = channelList[k].ChildNodes;
                for (int i = 0; i < channelList[k].ChildNodes.Count; i++)
                {


                    switch (channelList[k].ChildNodes[i].Name)
                    {

                        case "item":
                            noOfItemInChannel++;
                            XmlNodeList xmlChildNodeOfItem = channelList[k].ChildNodes[i].ChildNodes;
                            //debugging
                            //Console.WriteLine("Thread Name in item in RssFileReader" + Thread.CurrentThread.Name);

                            rssDocumentObject.ListOfChannel[k].ListOfItem.Add(new Item());

                            for (int j = 0; j < xmlChildNodeOfItem.Count; j++)
                            {
                                switch (xmlChildNodeOfItem[j].Name)
                                {
                                    case "title":
                                        rssDocumentObject.ListOfChannel[k].ListOfItem[noOfItemInChannel].ItemTitle.InnerText = xmlChildNodeOfItem[j].InnerText;
                                        break;
                                    case "link":
                                        rssDocumentObject.ListOfChannel[k].ListOfItem[noOfItemInChannel].ItemLink.InnerText = xmlChildNodeOfItem[j].InnerText;
                                        break;
                                    case "description":
                                        rssDocumentObject.ListOfChannel[k].ListOfItem[noOfItemInChannel].ItemDescription.InnerText = xmlChildNodeOfItem[j].InnerText;
                                        break;
                                    case "pubDate":
                                        try
                                        {
                                            string dateTimeTemp = xmlChildNodeOfItem[j].InnerText;
                                            char[] splitCharArray = new char[1];
                                            splitCharArray[0] = ' ';
                                            string[] splitedDateTimeTemp = dateTimeTemp.Split(splitCharArray);
                                            string RFC822 = "ddd,ddMMMyyyyHH:mm:ss";
                                            rssDocumentObject.ListOfChannel[k].ListOfItem[noOfItemInChannel].ItemPubDate.PublicationDate = DateTime.ParseExact(splitedDateTimeTemp[0] + splitedDateTimeTemp[1] + splitedDateTimeTemp[2] + splitedDateTimeTemp[3] + splitedDateTimeTemp[4], RFC822, DateTimeFormatInfo.InvariantInfo, DateTimeStyles.None);
                                        }
                                        //exception not rethrown default date is assigned 
                                        catch (Exception e)
                                        {
                                            //Console.WriteLine("Exception while formatting string to datetime in rssFileReader():" + e);
                                        }
                                        break;
                                    case "guid":
                                        rssDocumentObject.ListOfChannel[k].ListOfItem[noOfItemInChannel].ItemGuid.InnerText = xmlChildNodeOfItem[j].InnerText;
                                        break;


                                }
                            }
                            break;
                        case "title":
                            rssDocumentObject.ListOfChannel[k].ChannelTitle.InnerText = channelList[k].ChildNodes[i].InnerText;
                            break;
                        case "description":
                            rssDocumentObject.ListOfChannel[k].ChannelDescription.InnerText = channelList[k].ChildNodes[i].InnerText;
                            break;
                        case "link":
                            rssDocumentObject.ListOfChannel[k].ChannelLink.InnerText = channelList[k].ChildNodes[i].InnerText;
                            break;

                        case "language":
                            rssDocumentObject.ListOfChannel[k].ChannelLanguage.InnerText = channelList[k].ChildNodes[i].InnerText;
                            break;
                        case "pubDate":
                            try
                            {
                                string dateTimeTempForChannel = channelList[k].ChildNodes[i].InnerText;
                                char[] splitCharArrayForChannel = new char[1];
                                splitCharArrayForChannel[0] = ' ';
                                string[] splitedDateTimeTempForChannel = dateTimeTempForChannel.Split(splitCharArrayForChannel);
                                string formatStringForChannel = "ddd,ddMMMyyyyHH:mm:ss";
                                rssDocumentObject.ListOfChannel[k].ChannelPubDate.PublicationDate = DateTime.ParseExact(splitedDateTimeTempForChannel[0] + splitedDateTimeTempForChannel[1] + splitedDateTimeTempForChannel[2] + splitedDateTimeTempForChannel[3] + splitedDateTimeTempForChannel[4], formatStringForChannel, DateTimeFormatInfo.InvariantInfo, DateTimeStyles.None);
                            }
                            //exception not rethrown default date is assigned 
                            catch (Exception e)
                            {
                                //Console.WriteLine("Exception while formatting string to datetime in rssFileReader():" + e);

                            }
                            break;
                        case "lastBuildDate":
                            try
                            {
                                string dateTimeTempForChannel = channelList[k].ChildNodes[i].InnerText;
                                char[] splitCharArrayForChannel = new char[1];
                                splitCharArrayForChannel[0] = ' ';
                                string formatStringForChannel = "ddd,ddMMMyyyyHH:mm:ss";

                                string[] splitedDateTimeTempForChannel = dateTimeTempForChannel.Split(splitCharArrayForChannel);
                                rssDocumentObject.ListOfChannel[k].ChannelLastBuildDate.LastBldDate = DateTime.ParseExact(splitedDateTimeTempForChannel[0] + splitedDateTimeTempForChannel[1] + splitedDateTimeTempForChannel[2] + splitedDateTimeTempForChannel[3] + splitedDateTimeTempForChannel[4], formatStringForChannel, DateTimeFormatInfo.InvariantInfo, DateTimeStyles.None);
                            }
                            //exception not rethrown default date is assigned 
                            catch (Exception e)
                            {
                                //Console.WriteLine("Exception while formatting string to datetime in rssFileReader():" + e);

                            }

                            break;

                        case "docs":
                            rssDocumentObject.ListOfChannel[k].ChannelDocs.InnerText = channelList[k].ChildNodes[i].InnerText;
                            break;
                        case "generator":
                            rssDocumentObject.ListOfChannel[k].ChannelGenerator.InnerText = channelList[k].ChildNodes[i].InnerText;
                            break;
                        case "managingEditor":
                            rssDocumentObject.ListOfChannel[k].ChannelManagingEditor.InnerText = channelList[k].ChildNodes[i].InnerText;
                            break;
                        case "webMaster":
                            rssDocumentObject.ListOfChannel[k].ChannelWebMaster.InnerText = channelList[k].ChildNodes[i].InnerText;
                            break;
                        case "ttl":
                            rssDocumentObject.ListOfChannel[k].ChannelTtl.InnerText = channelList[k].ChildNodes[i].InnerText;
                            break;

                    }
                }


            }
        }
        catch(Exception e)
        {
            e.Source = "RssFileReader:Reading xml document object data to rss object";
            throw;
        }
        Console.WriteLine("    Thread out RssFilereader :" + Thread.CurrentThread.Name);
        return rssDocumentObject;
    }
}

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note:-while debugging i got to know that its taking time while loading xml document. is there any limit imposed on system for number of webrequest objects?

Answer 1

If you're using web requests to the same server, those are throttled by default to two connections at a time.

You're then failing to dispose of the response and response stream, which means it'll wait until it's garbage collected to release the connection for use elsewhere. Change your loading code to:

    try
    {
        // Removed unnecessary @ signs
        using (WebResponse response = HttpClient.GetWebResponse(
                  rssFeed, null, null, 1200000, "http://www.sahil.com"))
        using (Stream responseStream = response.GetResponseStream())
        {
            documentObj.Load(responseStream);
        }
    }
    catch(Exception e)
    {
        e.Source = "RssFileReader:Loading xmldocument object";
        throw;
    }

It's possible that you only need to close the web response - that the stream will be taken care of by closing the response - but it's better to be sure.

You'll still only get two threads using connections to the same server at the same time (by default, for non-ASP.NET; you can change this yourself using ServicePointManager.DefaultConnectionLimit or the connectionManagement config file element ) but at least then you won't need to wait while the connection idles out or waits for garbage collection.

Answer 2

it was taking time when i was running it from console applcation fr testing. reason fo much time taken was io blocking because of pint statements fr debugging.