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  • ANTS CLR and Memory Profiler In Depth Review (Part 1 of 2 &ndash; CLR Profiler)

    - by ToStringTheory
    One of the things that people might not know about me, is my obsession to make my code as efficient as possible.  Many people might not realize how much of a task or undertaking that this might be, but it is surely a task as monumental as climbing Mount Everest, except this time it is a challenge for the mind…  In trying to make code efficient, there are many different factors that play a part – size of project or solution, tiers, language used, experience and training of the programmer, technologies used, maintainability of the code – the list can go on for quite some time. I spend quite a bit of time when developing trying to determine what is the best way to implement a feature to accomplish the efficiency that I look to achieve.  One program that I have recently come to learn about – Red Gate ANTS Performance (CLR) and Memory profiler gives me tools to accomplish that job more efficiently as well.  In this review, I am going to cover some of the features of the ANTS profiler set by compiling some hideous example code to test against. Notice As a member of the Geeks With Blogs Influencers program, one of the perks is the ability to review products, in exchange for a free license to the program.  I have not let this affect my opinions of the product in any way, and Red Gate nor Geeks With Blogs has tried to influence my opinion regarding this product in any way. Introduction The ANTS Profiler pack provided by Red Gate was something that I had not heard of before receiving an email regarding an offer to review it for a license.  Since I look to make my code efficient, it was a no brainer for me to try it out!  One thing that I have to say took me by surprise is that upon downloading the program and installing it you fill out a form for your usual contact information.  Sure enough within 2 hours, I received an email from a sales representative at Red Gate asking if she could help me to achieve the most out of my trial time so it wouldn’t go to waste.  After replying to her and explaining that I was looking to review its feature set, she put me in contact with someone that setup a demo session to give me a quick rundown of its features via an online meeting.  After having dealt with a massive ordeal with one of my utility companies and their complete lack of customer service, Red Gates friendly and helpful representatives were a breath of fresh air, and something I was thankful for. ANTS CLR Profiler The ANTS CLR profiler is the thing I want to focus on the most in this post, so I am going to dive right in now. Install was simple and took no time at all.  It installed both the profiler for the CLR and Memory, but also visual studio extensions to facilitate the usage of the profilers (click any images for full size images): The Visual Studio menu options (under ANTS menu) Starting the CLR Performance Profiler from the start menu yields this window If you follow the instructions after launching the program from the start menu (Click File > New Profiling Session to start a new project), you are given a dialog with plenty of options for profiling: The New Session dialog.  Lots of options.  One thing I noticed is that the buttons in the lower right were half-covered by the panel of the application.  If I had to guess, I would imagine that this is caused by my DPI settings being set to 125%.  This is a problem I have seen in other applications as well that don’t scale well to different dpi scales. The profiler options give you the ability to profile: .NET Executable ASP.NET web application (hosted in IIS) ASP.NET web application (hosted in IIS express) ASP.NET web application (hosted in Cassini Web Development Server) SharePoint web application (hosted in IIS) Silverlight 4+ application Windows Service COM+ server XBAP (local XAML browser application) Attach to an already running .NET 4 process Choosing each option provides a varying set of other variables/options that one can set including options such as application arguments, operating path, record I/O performance performance counters to record (43 counters in all!), etc…  All in all, they give you the ability to profile many different .Net project types, and make it simple to do so.  In most cases of my using this application, I would be using the built in Visual Studio extensions, as they automatically start a new profiling project in ANTS with the options setup, and start your program, however RedGate has made it easy enough to profile outside of Visual Studio as well. On the flip side of this, as someone who lives most of their work life in Visual Studio, one thing I do wish is that instead of opening an entirely separate application/gui to perform profiling after launching, that instead they would provide a Visual Studio panel with the information, and integrate more of the profiling project information into Visual Studio.  So, now that we have an idea of what options that the profiler gives us, its time to test its abilities and features. Horrendous Example Code – Prime Number Generator One of my interests besides development, is Physics and Math – what I went to college for.  I have especially always been interested in prime numbers, as they are something of a mystery…  So, I decided that I would go ahead and to test the abilities of the profiler, I would write a small program, website, and library to generate prime numbers in the quantity that you ask for.  I am going to start off with some terrible code, and show how I would see the profiler being used as a development tool. First off, the IPrimes interface (all code is downloadable at the end of the post): interface IPrimes { IEnumerable<int> GetPrimes(int retrieve); } Simple enough, right?  Anything that implements the interface will (hopefully) provide an IEnumerable of int, with the quantity specified in the parameter argument.  Next, I am going to implement this interface in the most basic way: public class DumbPrimes : IPrimes { public IEnumerable<int> GetPrimes(int retrieve) { //store a list of primes already found var _foundPrimes = new List<int>() { 2, 3 }; //if i ask for 1 or two primes, return what asked for if (retrieve <= _foundPrimes.Count()) return _foundPrimes.Take(retrieve); //the next number to look at int _analyzing = 4; //since I already determined I don't have enough //execute at least once, and until quantity is sufficed do { //assume prime until otherwise determined bool isPrime = true; //start dividing at 2 //divide until number is reached, or determined not prime for (int i = 2; i < _analyzing && isPrime; i++) { //if (i) goes into _analyzing without a remainder, //_analyzing is NOT prime if (_analyzing % i == 0) isPrime = false; } //if it is prime, add to found list if (isPrime) _foundPrimes.Add(_analyzing); //increment number to analyze next _analyzing++; } while (_foundPrimes.Count() < retrieve); return _foundPrimes; } } This is the simplest way to get primes in my opinion.  Checking each number by the straight definition of a prime – is it divisible by anything besides 1 and itself. I have included this code in a base class library for my solution, as I am going to use it to demonstrate a couple of features of ANTS.  This class library is consumed by a simple non-MVVM WPF application, and a simple MVC4 website.  I will not post the WPF code here inline, as it is simply an ObservableCollection<int>, a label, two textbox’s, and a button. Starting a new Profiling Session So, in Visual Studio, I have just completed my first stint developing the GUI and DumbPrimes IPrimes class, so now I want to check my codes efficiency by profiling it.  All I have to do is build the solution (surprised initiating a profiling session doesn’t do this, but I suppose I can understand it), and then click the ANTS menu, followed by Profile Performance.  I am then greeted by the profiler starting up and already monitoring my program live: You are provided with a realtime graph at the top, and a pane at the bottom giving you information on how to proceed.  I am going to start by asking my program to show me the first 15000 primes: After the program finally began responding again (I did all the work on the main UI thread – how bad!), I stopped the profiler, which did kill the process of my program too.  One important thing to note, is that the profiler by default wants to give you a lot of detail about the operation – line hit counts, time per line, percent time per line, etc…  The important thing to remember is that this itself takes a lot of time.  When running my program without the profiler attached, it can generate the 15000 primes in 5.18 seconds, compared to 74.5 seconds – almost a 1500 percent increase.  While this may seem like a lot, remember that there is a trade off.  It may be WAY more inefficient, however, I am able to drill down and make improvements to specific problem areas, and then decrease execution time all around. Analyzing the Profiling Session After clicking ‘Stop Profiling’, the process running my application stopped, and the entire execution time was automatically selected by ANTS, and the results shown below: Now there are a number of interesting things going on here, I am going to cover each in a section of its own: Real Time Performance Counter Bar (top of screen) At the top of the screen, is the real time performance bar.  As your application is running, this will constantly update with the currently selected performance counters status.  A couple of cool things to note are the fact that you can drag a selection around specific time periods to drill down the detail views in the lower 2 panels to information pertaining to only that period. After selecting a time period, you can bookmark a section and name it, so that it is easy to find later, or after reloaded at a later time.  You can also zoom in, out, or fit the graph to the space provided – useful for drilling down. It may be hard to see, but at the top of the processor time graph below the time ticks, but above the red usage graph, there is a green bar. This bar shows at what times a method that is selected in the ‘Call tree’ panel is called. Very cool to be able to click on a method and see at what times it made an impact. As I said before, ANTS provides 43 different performance counters you can hook into.  Click the arrow next to the Performance tab at the top will allow you to change between different counters if you have them selected: Method Call Tree, ADO.Net Database Calls, File IO – Detail Panel Red Gate really hit the mark here I think. When you select a section of the run with the graph, the call tree populates to fill a hierarchical tree of method calls, with information regarding each of the methods.   By default, methods are hidden where the source is not provided (framework type code), however, Red Gate has integrated Reflector into ANTS, so even if you don’t have source for something, you can select a method and get the source if you want.  Methods are also hidden where the impact is seen as insignificant – methods that are only executed for 1% of the time of the overall calling methods time; in other words, working on making them better is not where your efforts should be focused. – Smart! Source Panel – Detail Panel The source panel is where you can see line level information on your code, showing the code for the currently selected method from the Method Call Tree.  If the code is not available, Reflector takes care of it and shows the code anyways! As you can notice, there does seem to be a problem with how ANTS determines what line is the actual line that a call is completed on.  I have suspicions that this may be due to some of the inline code optimizations that the CLR applies upon compilation of the assembly.  In a method with comments, the problem is much more severe: As you can see here, apparently the most offending code in my base library was a comment – *gasp*!  Removing the comments does help quite a bit, however I hope that Red Gate works on their counter algorithm soon to improve the logic on positioning for statistics: I did a small test just to demonstrate the lines are correct without comments. For me, it isn’t a deal breaker, as I can usually determine the correct placements by looking at the application code in the region and determining what makes sense, but it is something that would probably build up some irritation with time. Feature – Suggest Method for Optimization A neat feature to really help those in need of a pointer, is the menu option under tools to automatically suggest methods to optimize/improve: Nice feature – clicking it filters the call tree and stars methods that it thinks are good candidates for optimization.  I do wish that they would have made it more visible for those of use who aren’t great on sight: Process Integration I do think that this could have a place in my process.  After experimenting with the profiler, I do think it would be a great benefit to do some development, testing, and then after all the bugs are worked out, use the profiler to check on things to make sure nothing seems like it is hogging more than its fair share.  For example, with this program, I would have developed it, ran it, tested it – it works, but slowly. After looking at the profiler, and seeing the massive amount of time spent in 1 method, I might go ahead and try to re-implement IPrimes (I actually would probably rewrite the offending code, but so that I can distribute both sets of code easily, I’m just going to make another implementation of IPrimes).  Using two pieces of knowledge about prime numbers can make this method MUCH more efficient – prime numbers fall into two buckets 6k+/-1 , and a number is prime if it is not divisible by any other primes before it: public class SmartPrimes : IPrimes { public IEnumerable<int> GetPrimes(int retrieve) { //store a list of primes already found var _foundPrimes = new List<int>() { 2, 3 }; //if i ask for 1 or two primes, return what asked for if (retrieve <= _foundPrimes.Count()) return _foundPrimes.Take(retrieve); //the next number to look at int _k = 1; //since I already determined I don't have enough //execute at least once, and until quantity is sufficed do { //assume prime until otherwise determined bool isPrime = true; int potentialPrime; //analyze 6k-1 //assign the value to potential potentialPrime = 6 * _k - 1; //if there are any primes that divise this, it is NOT a prime number //using PLINQ for quick boost isPrime = !_foundPrimes.AsParallel() .Any(prime => potentialPrime % prime == 0); //if it is prime, add to found list if (isPrime) _foundPrimes.Add(potentialPrime); if (_foundPrimes.Count() == retrieve) break; //analyze 6k+1 //assign the value to potential potentialPrime = 6 * _k + 1; //if there are any primes that divise this, it is NOT a prime number //using PLINQ for quick boost isPrime = !_foundPrimes.AsParallel() .Any(prime => potentialPrime % prime == 0); //if it is prime, add to found list if (isPrime) _foundPrimes.Add(potentialPrime); //increment k to analyze next _k++; } while (_foundPrimes.Count() < retrieve); return _foundPrimes; } } Now there are definitely more things I can do to help make this more efficient, but for the scope of this example, I think this is fine (but still hideous)! Profiling this now yields a happy surprise 27 seconds to generate the 15000 primes with the profiler attached, and only 1.43 seconds without.  One important thing I wanted to call out though was the performance graph now: Notice anything odd?  The %Processor time is above 100%.  This is because there is now more than 1 core in the operation.  A better label for the chart in my mind would have been %Core time, but to each their own. Another odd thing I noticed was that the profiler seemed to be spot on this time in my DumbPrimes class with line details in source, even with comments..  Odd. Profiling Web Applications The last thing that I wanted to cover, that means a lot to me as a web developer, is the great amount of work that Red Gate put into the profiler when profiling web applications.  In my solution, I have a simple MVC4 application setup with 1 page, a single input form, that will output prime values as my WPF app did.  Launching the profiler from Visual Studio as before, nothing is really different in the profiler window, however I did receive a UAC prompt for a Red Gate helper app to integrate with the web server without notification. After requesting 500, 1000, 2000, and 5000 primes, and looking at the profiler session, things are slightly different from before: As you can see, there are 4 spikes of activity in the processor time graph, but there is also something new in the call tree: That’s right – ANTS will actually group method calls by get/post operations, so it is easier to find out what action/page is giving the largest problems…  Pretty cool in my mind! Overview Overall, I think that Red Gate ANTS CLR Profiler has a lot to offer, however I think it also has a long ways to go.  3 Biggest Pros: Ability to easily drill down from time graph, to method calls, to source code Wide variety of counters to choose from when profiling your application Excellent integration/grouping of methods being called from web applications by request – BRILLIANT! 3 Biggest Cons: Issue regarding line details in source view Nit pick – Processor time vs. Core time Nit pick – Lack of full integration with Visual Studio Ratings Ease of Use (7/10) – I marked down here because of the problems with the line level details and the extra work that that entails, and the lack of better integration with Visual Studio. Effectiveness (10/10) – I believe that the profiler does EXACTLY what it purports to do.  Especially with its large variety of performance counters, a definite plus! Features (9/10) – Besides the real time performance monitoring, and the drill downs that I’ve shown here, ANTS also has great integration with ADO.Net, with the ability to show database queries run by your application in the profiler.  This, with the line level details, the web request grouping, reflector integration, and various options to customize your profiling session I think create a great set of features! Customer Service (10/10) – My entire experience with Red Gate personnel has been nothing but good.  their people are friendly, helpful, and happy! UI / UX (8/10) – The interface is very easy to get around, and all of the options are easy to find.  With a little bit of poking around, you’ll be optimizing Hello World in no time flat! Overall (8/10) – Overall, I am happy with the Performance Profiler and its features, as well as with the service I received when working with the Red Gate personnel.  I WOULD recommend you trying the application and seeing if it would fit into your process, BUT, remember there are still some kinks in it to hopefully be worked out. My next post will definitely be shorter (hopefully), but thank you for reading up to here, or skipping ahead!  Please, if you do try the product, drop me a message and let me know what you think!  I would love to hear any opinions you may have on the product. Code Feel free to download the code I used above – download via DropBox

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  • Scaling-out Your Services by Message Bus based WCF Transport Extension &ndash; Part 1 &ndash; Background

    - by Shaun
    Cloud computing gives us more flexibility on the computing resource, we can provision and deploy an application or service with multiple instances over multiple machines. With the increment of the service instances, how to balance the incoming message and workload would become a new challenge. Currently there are two approaches we can use to pass the incoming messages to the service instances, I would like call them dispatcher mode and pulling mode.   Dispatcher Mode The dispatcher mode introduces a role which takes the responsible to find the best service instance to process the request. The image below describes the sharp of this mode. There are four clients communicate with the service through the underlying transportation. For example, if we are using HTTP the clients might be connecting to the same service URL. On the server side there’s a dispatcher listening on this URL and try to retrieve all messages. When a message came in, the dispatcher will find a proper service instance to process it. There are three mechanism to find the instance: Round-robin: Dispatcher will always send the message to the next instance. For example, if the dispatcher sent the message to instance 2, then the next message will be sent to instance 3, regardless if instance 3 is busy or not at that moment. Random: Dispatcher will find a service instance randomly, and same as the round-robin mode it regardless if the instance is busy or not. Sticky: Dispatcher will send all related messages to the same service instance. This approach always being used if the service methods are state-ful or session-ful. But as you can see, all of these approaches are not really load balanced. The clients will send messages at any time, and each message might take different process duration on the server side. This means in some cases, some of the service instances are very busy while others are almost idle. For example, if we were using round-robin mode, it could be happened that most of the simple task messages were passed to instance 1 while the complex ones were sent to instance 3, even though instance 1 should be idle. This brings some problem in our architecture. The first one is that, the response to the clients might be longer than it should be. As it’s shown in the figure above, message 6 and 9 can be processed by instance 1 or instance 2, but in reality they were dispatched to the busy instance 3 since the dispatcher and round-robin mode. Secondly, if there are many requests came from the clients in a very short period, service instances might be filled by tons of pending tasks and some instances might be crashed. Third, if we are using some cloud platform to host our service instances, for example the Windows Azure, the computing resource is billed by service deployment period instead of the actual CPU usage. This means if any service instance is idle it is wasting our money! Last one, the dispatcher would be the bottleneck of our system since all incoming messages must be routed by the dispatcher. If we are using HTTP or TCP as the transport, the dispatcher would be a network load balance. If we wants more capacity, we have to scale-up, or buy a hardware load balance which is very expensive, as well as scaling-out the service instances. Pulling Mode Pulling mode doesn’t need a dispatcher to route the messages. All service instances are listening to the same transport and try to retrieve the next proper message to process if they are idle. Since there is no dispatcher in pulling mode, it requires some features on the transportation. The transportation must support multiple client connection and server listening. HTTP and TCP doesn’t allow multiple clients are listening on the same address and port, so it cannot be used in pulling mode directly. All messages in the transportation must be FIFO, which means the old message must be received before the new one. Message selection would be a plus on the transportation. This means both service and client can specify some selection criteria and just receive some specified kinds of messages. This feature is not mandatory but would be very useful when implementing the request reply and duplex WCF channel modes. Otherwise we must have a memory dictionary to store the reply messages. I will explain more about this in the following articles. Message bus, or the message queue would be best candidate as the transportation when using the pulling mode. First, it allows multiple application to listen on the same queue, and it’s FIFO. Some of the message bus also support the message selection, such as TIBCO EMS, RabbitMQ. Some others provide in memory dictionary which can store the reply messages, for example the Redis. The principle of pulling mode is to let the service instances self-managed. This means each instance will try to retrieve the next pending incoming message if they finished the current task. This gives us more benefit and can solve the problems we met with in the dispatcher mode. The incoming message will be received to the best instance to process, which means this will be very balanced. And it will not happen that some instances are busy while other are idle, since the idle one will retrieve more tasks to make them busy. Since all instances are try their best to be busy we can use less instances than dispatcher mode, which more cost effective. Since there’s no dispatcher in the system, there is no bottleneck. When we introduced more service instances, in dispatcher mode we have to change something to let the dispatcher know the new instances. But in pulling mode since all service instance are self-managed, there no extra change at all. If there are many incoming messages, since the message bus can queue them in the transportation, service instances would not be crashed. All above are the benefits using the pulling mode, but it will introduce some problem as well. The process tracking and debugging become more difficult. Since the service instances are self-managed, we cannot know which instance will process the message. So we need more information to support debug and track. Real-time response may not be supported. All service instances will process the next message after the current one has done, if we have some real-time request this may not be a good solution. Compare with the Pros and Cons above, the pulling mode would a better solution for the distributed system architecture. Because what we need more is the scalability, cost-effect and the self-management.   WCF and WCF Transport Extensibility Windows Communication Foundation (WCF) is a framework for building service-oriented applications. In the .NET world WCF is the best way to implement the service. In this series I’m going to demonstrate how to implement the pulling mode on top of a message bus by extending the WCF. I don’t want to deep into every related field in WCF but will highlight its transport extensibility. When we implemented an RPC foundation there are many aspects we need to deal with, for example the message encoding, encryption, authentication and message sending and receiving. In WCF, each aspect is represented by a channel. A message will be passed through all necessary channels and finally send to the underlying transportation. And on the other side the message will be received from the transport and though the same channels until the business logic. This mode is called “Channel Stack” in WCF, and the last channel in the channel stack must always be a transport channel, which takes the responsible for sending and receiving the messages. As we are going to implement the WCF over message bus and implement the pulling mode scaling-out solution, we need to create our own transport channel so that the client and service can exchange messages over our bus. Before we deep into the transport channel, let’s have a look on the message exchange patterns that WCF defines. Message exchange pattern (MEP) defines how client and service exchange the messages over the transportation. WCF defines 3 basic MEPs which are datagram, Request-Reply and Duplex. Datagram: Also known as one-way, or fire-forgot mode. The message sent from the client to the service, and no need any reply from the service. The client doesn’t care about the message result at all. Request-Reply: Very common used pattern. The client send the request message to the service and wait until the reply message comes from the service. Duplex: The client sent message to the service, when the service processing the message it can callback to the client. When callback the service would be like a client while the client would be like a service. In WCF, each MEP represent some channels associated. MEP Channels Datagram IInputChannel, IOutputChannel Request-Reply IRequestChannel, IReplyChannel Duplex IDuplexChannel And the channels are created by ChannelListener on the server side, and ChannelFactory on the client side. The ChannelListener and ChannelFactory are created by the TransportBindingElement. The TransportBindingElement is created by the Binding, which can be defined as a new binding or from a custom binding. For more information about the transport channel mode, please refer to the MSDN document. The figure below shows the transport channel objects when using the request-reply MEP. And this is the datagram MEP. And this is the duplex MEP. After investigated the WCF transport architecture, channel mode and MEP, we finally identified what we should do to extend our message bus based transport layer. They are: Binding: (Optional) Defines the channel elements in the channel stack and added our transport binding element at the bottom of the stack. But we can use the build-in CustomBinding as well. TransportBindingElement: Defines which MEP is supported in our transport and create the related ChannelListener and ChannelFactory. This also defines the scheme of the endpoint if using this transport. ChannelListener: Create the server side channel based on the MEP it’s. We can have one ChannelListener to create channels for all supported MEPs, or we can have ChannelListener for each MEP. In this series I will use the second approach. ChannelFactory: Create the client side channel based on the MEP it’s. We can have one ChannelFactory to create channels for all supported MEPs, or we can have ChannelFactory for each MEP. In this series I will use the second approach. Channels: Based on the MEPs we want to support, we need to implement the channels accordingly. For example, if we want our transport support Request-Reply mode we should implement IRequestChannel and IReplyChannel. In this series I will implement all 3 MEPs listed above one by one. Scaffold: In order to make our transport extension works we also need to implement some scaffold stuff. For example we need some classes to send and receive message though out message bus. We also need some codes to read and write the WCF message, etc.. These are not necessary but would be very useful in our example.   Message Bus There is only one thing remained before we can begin to implement our scaling-out support WCF transport, which is the message bus. As I mentioned above, the message bus must have some features to fulfill all the WCF MEPs. In my company we will be using TIBCO EMS, which is an enterprise message bus product. And I have said before we can use any message bus production if it’s satisfied with our requests. Here I would like to introduce an interface to separate the message bus from the WCF. This allows us to implement the bus operations by any kinds bus we are going to use. The interface would be like this. 1: public interface IBus : IDisposable 2: { 3: string SendRequest(string message, bool fromClient, string from, string to = null); 4:  5: void SendReply(string message, bool fromClient, string replyTo); 6:  7: BusMessage Receive(bool fromClient, string replyTo); 8: } There are only three methods for the bus interface. Let me explain one by one. The SendRequest method takes the responsible for sending the request message into the bus. The parameters description are: message: The WCF message content. fromClient: Indicates if this message was came from the client. from: The channel ID that this message was sent from. The channel ID will be generated when any kinds of channel was created, which will be explained in the following articles. to: The channel ID that this message should be received. In Request-Reply and Duplex MEP this is necessary since the reply message must be received by the channel which sent the related request message. The SendReply method takes the responsible for sending the reply message. It’s very similar as the previous one but no “from” parameter. This is because it’s no need to reply a reply message again in any MEPs. The Receive method takes the responsible for waiting for a incoming message, includes the request message and specified reply message. It returned a BusMessage object, which contains some information about the channel information. The code of the BusMessage class is 1: public class BusMessage 2: { 3: public string MessageID { get; private set; } 4: public string From { get; private set; } 5: public string ReplyTo { get; private set; } 6: public string Content { get; private set; } 7:  8: public BusMessage(string messageId, string fromChannelId, string replyToChannelId, string content) 9: { 10: MessageID = messageId; 11: From = fromChannelId; 12: ReplyTo = replyToChannelId; 13: Content = content; 14: } 15: } Now let’s implement a message bus based on the IBus interface. Since I don’t want you to buy and install the TIBCO EMS or any other message bus products, I will implement an in process memory bus. This bus is only for test and sample purpose. It can only be used if the service and client are in the same process. Very straightforward. 1: public class InProcMessageBus : IBus 2: { 3: private readonly ConcurrentDictionary<Guid, InProcMessageEntity> _queue; 4: private readonly object _lock; 5:  6: public InProcMessageBus() 7: { 8: _queue = new ConcurrentDictionary<Guid, InProcMessageEntity>(); 9: _lock = new object(); 10: } 11:  12: public string SendRequest(string message, bool fromClient, string from, string to = null) 13: { 14: var entity = new InProcMessageEntity(message, fromClient, from, to); 15: _queue.TryAdd(entity.ID, entity); 16: return entity.ID.ToString(); 17: } 18:  19: public void SendReply(string message, bool fromClient, string replyTo) 20: { 21: var entity = new InProcMessageEntity(message, fromClient, null, replyTo); 22: _queue.TryAdd(entity.ID, entity); 23: } 24:  25: public BusMessage Receive(bool fromClient, string replyTo) 26: { 27: InProcMessageEntity e = null; 28: while (true) 29: { 30: lock (_lock) 31: { 32: var entity = _queue 33: .Where(kvp => kvp.Value.FromClient == fromClient && (kvp.Value.To == replyTo || string.IsNullOrWhiteSpace(kvp.Value.To))) 34: .FirstOrDefault(); 35: if (entity.Key != Guid.Empty && entity.Value != null) 36: { 37: _queue.TryRemove(entity.Key, out e); 38: } 39: } 40: if (e == null) 41: { 42: Thread.Sleep(100); 43: } 44: else 45: { 46: return new BusMessage(e.ID.ToString(), e.From, e.To, e.Content); 47: } 48: } 49: } 50:  51: public void Dispose() 52: { 53: } 54: } The InProcMessageBus stores the messages in the objects of InProcMessageEntity, which can take some extra information beside the WCF message itself. 1: public class InProcMessageEntity 2: { 3: public Guid ID { get; set; } 4: public string Content { get; set; } 5: public bool FromClient { get; set; } 6: public string From { get; set; } 7: public string To { get; set; } 8:  9: public InProcMessageEntity() 10: : this(string.Empty, false, string.Empty, string.Empty) 11: { 12: } 13:  14: public InProcMessageEntity(string content, bool fromClient, string from, string to) 15: { 16: ID = Guid.NewGuid(); 17: Content = content; 18: FromClient = fromClient; 19: From = from; 20: To = to; 21: } 22: }   Summary OK, now I have all necessary stuff ready. The next step would be implementing our WCF message bus transport extension. In this post I described two scaling-out approaches on the service side especially if we are using the cloud platform: dispatcher mode and pulling mode. And I compared the Pros and Cons of them. Then I introduced the WCF channel stack, channel mode and the transport extension part, and identified what we should do to create our own WCF transport extension, to let our WCF services using pulling mode based on a message bus. And finally I provided some classes that need to be used in the future posts that working against an in process memory message bus, for the demonstration purpose only. In the next post I will begin to implement the transport extension step by step.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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  • Any career related single one-stop forum hub..

    - by learnerforever
    Hi, Stumbling into SO and then its sibling sites like programmers.stackexchange,superuser has been tremendously useful to me and is a single stop for my technical problems,long unanswered curiosities and it has been very useful to get perspective from mature professionals. I am an IT professional.I am looking for a similar one-stop career related forum, where I can understand job descriptions of different professions, career growth path, what a day looks like, salary,strengths needed with people having been there. I am confused about my career and particularly of interest are things like professors in academia,researchers in R&D lab, software developers,architectures,testers,business analyst,it analyst and related. Thanks,

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  • Intel HD graphic drivers for ubuntu 10.10 64bit: the brightness says its being adjusted but it isn't

    - by James
    Hey all, I picked up an hp dm3t laptop with intel HD graphics and installed ubuntu 10.10 64 bit on it. It works great -- the only problem is that the brightness controls on the keyboard don't work. The brightness is always at full. When I try to adjust it down, the indicator graphic indicates that it's going down but the actual brightness doesn't change. Is there anything that I can try to make this work? I'd really appreciate any help. I asked this on superuser.com and someone commented that I should play around with the intel hd drivers. I'm a total noob -- how do I do that? What else can I try? I reallly don't want to do back to windows.

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  • Share files - Ubuntu 12.4 and Windows 7 - one network - password not accepted

    - by gotqn
    I ask this question in SuperUser but no one helps me. I hope to get more attention here. I have three computers connected in one network by modem. I want to share files in this network in the most easy way (I have read about solutions using Samba). So, I have three machines: One with Windows 7 One with Windows XP One with Ubuntu 12.04 and I have the following situation: The windows PCs can share files between each other. The windows PCs can see that Ubuntu's one is in the network The PC with Ubuntu can see only the PC with Windows 7, but when I click on a folder it ask to enter the network password and it is not accepting it (I am 100% sure it's the correct one) Is there to fix this situation a little bit - at least to enable the file sharing between the Ubuntu and Windows 7 PCs or I should choose a different approach (please advice).

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  • Sharing internet to Ubuntu 12.04 VMWare guest

    - by John Cogan
    Got the 12.04 distro and installed this on my Mac VMWare Fusion (Version 4.1.2). Install went fine and Ubuntu seemed to update itself during the install. Rebooted and now I cannot get Ubuntu to access the internet via my Macs Ethernet connection (Connected to a router) Have tried settings the VMWare network adaptor to NAT or bridged and Host only without success. In Ubuntu I have the eth0 set to Automatic DHCP. VMWare tools is installed as well. I know next to nothing about what to do here and net searches on both Stackoverflow and Superuser sites are producing not results for me. Could someone please help? What to eventually have Ubuntu run in the background as a development web server running Zend Framework and CE Server edition but need thew internet access to run updates etc on Ubuntu. Any help would be really appreciated. TIA John

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  • Hosted version of Yahoo! answers

    - by Neil
    Hi all. Does anyone know of a hosted version of Yahoo! Answers (or Stackoverflow/Superuser) that I could integrate with my site? I know that there are some open-source implementations (see http://meta.stackoverflow.com/questions/2267/stack-overflow-clones?page=1&tab=votes#tab-top) but I'd rather have some hosted if possible. I know there is http://stackexchange.com/ as well, but I really want some tight integration with the rest of my site. Failing that, has anyone got any experience with the open source versions? Some of them look a little, erm, unfinished... Thanks. Neil.

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  • What Is Disk Fragmentation and Do I Still Need to Defragment?

    - by Jason Fitzpatrick
    Do modern computers still need the kind of routine defragmentation procedures that older computers called for? Read on to learn about fragmentation and what modern operating systems and file systems do to minimize performance impacts. Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-drive grouping of Q&A web sites. Secure Yourself by Using Two-Step Verification on These 16 Web Services How to Fix a Stuck Pixel on an LCD Monitor How to Factory Reset Your Android Phone or Tablet When It Won’t Boot

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  • Do Limited Wi-Fi Channels Restrict Network Availability?

    - by Jason Fitzpatrick
    Wi-Fi protocol supports 13 communication channels; how do these channels relate to the volume of devices you can have on the network and the quality of the connection? Read on learn more about Wi-Fi channel usage. Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-drive grouping of Q&A web sites. Why Does 64-Bit Windows Need a Separate “Program Files (x86)” Folder? Why Your Android Phone Isn’t Getting Operating System Updates and What You Can Do About It How To Delete, Move, or Rename Locked Files in Windows

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  • Looking for a light weight note program.

    - by Erin
    This might belongs on superuser but for me it's part of programming so i will ask it here. I find I use notepad to keep chunks of data that are important but not important enough to keep in my head. The one problem with this is I end up with a lot of files on my desktop that I don't know what they are for, or I don't save the file and my computer gets rebooted for some reason. So that big ramble leads to the question. I am looking for a note taking system that is light weight and easy to manage. I would rather it not be a huge application like onenote but if that is what you are using and is is working well for you could you explain how you are doing it? Thanks Erin.

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  • Why is a # sign added to the end of URLS?

    - by Niro
    Note: I'm asking this from the perspective of the site developers (trying to help someone there). not as a user. Please don't forward this to superuser.com. It's a server admin question. Have a look here http://www.wanimo.com/fr/chiens/coussin-matelas-tapis-pour-chien-sc28/tapis-plat-urban-chic-sf7263/ you'll see that the page gets redirected to the same page with # at the end. Worse, when you click back you get garbage url. I'm trying to debug what is causing the redirect. Any advice on how to find it ?

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  • Should I Leave My Laptop Plugged In All The Time?

    - by Jason Fitzpatrick
    Should you leave your laptop plugged in and charging when you’re not on-the-go? What’s best for the battery? What’s best for your user experience? Read on as we investigate. Image available as wallpaper-size download here. Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-drive grouping of Q&A web sites. 8 Deadly Commands You Should Never Run on Linux 14 Special Google Searches That Show Instant Answers How To Create a Customized Windows 7 Installation Disc With Integrated Updates

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  • Alternatives to Project Euler for improving Excel ability

    - by Jonathan Deamer
    I've recently been enjoying using the mathematical problems listed at Project Euler to learn Python. My Excel ability is better than my Python, but I think I'd still benefit from the sort of inductive learning that comes with solving a series of increasingly difficult puzzles using a particular tool. I know Project Euler can be completed using Excel, but are there any other puzzle series similar to this or The Python Challenge specifically tailored for people trying to increase their knowledge of Excel and what it can do? NB. I'm not looking for a "tutorial", I know there are plenty of these. And apologies if this isn't completely appropriate for programmers.SE.com - some of the folks at SuperUser suggested it was a better fit here than there!

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  • What Are the Windows A: and B: Drives Used For?

    - by Jason Fitzpatrick
    The C: drive is the default installation location for Windows, if you have a CD/DVD drive on your machine it’s likely the D: drive, and any additional drives fall in line after that. What about the A: and B: drives? Image by Michael Holley. Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-drive grouping of Q&A web sites. HTG Explains: What is DNS? How To Switch Webmail Providers Without Losing All Your Email How To Force Windows Applications to Use a Specific CPU

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  • Brightness control not working on HP Pavilion dm3t (Intel GMA 4500MHD)

    - by James
    Hey all, I picked up an hp dm3t laptop with intel HD graphics and installed ubuntu 10.10 64 bit on it. It works great -- the only problem is that the brightness controls on the keyboard don't work. The brightness is always at full. When I try to adjust it down, the indicator graphic indicates that it's going down but the actual brightness doesn't change. Is there anything that I can try to make this work? I'd really appreciate any help. I asked this on superuser.com and someone commented that I should play around with the intel hd drivers. I'm a total noob -- how do I do that? What else can I try? I really don't want to go back to windows.

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  • What Exactly Does the Wattage Rating on a Power Supply Unit Mean?

    - by Jason Fitzpatrick
    Your PSU is rated 80 Plus Bronze and for 650 watts, but what exactly does that mean? Read on to see how wattage and power efficiency ratings translate to real world use. Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-drive grouping of Q&A web sites. How To Use USB Drives With the Nexus 7 and Other Android Devices Why Does 64-Bit Windows Need a Separate “Program Files (x86)” Folder? Why Your Android Phone Isn’t Getting Operating System Updates and What You Can Do About It

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  • Are Modern Computers Still Vulnerable to Damage via Magnets?

    - by Jason Fitzpatrick
    It’s such an oft repeated warning that it’s firmly embedded in nerd lore: bring a magnet anywhere near your precious computer and suffer the dire consequences. But is true? Is your computer one run in with a novelty magnet away from digital death? Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-drive grouping of Q&A web sites. How To Create a Customized Windows 7 Installation Disc With Integrated Updates How to Get Pro Features in Windows Home Versions with Third Party Tools HTG Explains: Is ReadyBoost Worth Using?

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  • Nautilus is extremely slow

    - by Maxim
    I am on Ubuntu 11.04. And Nautilus is very slow. It opens directories for 3-5 seconds even if a directory contains just a few small files. Even selecting of a file or directory with narrow keys is extremely slow and it rises my CPU usage up to 100%. It makes it almost unusable. But I noticed that if I start my nautilus as superuser: $ gksu nautilus then it works just fine. It is fast and responsive. So what can I do to fix this? Any help is really appreciated.

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  • knetworkmanager not starting at all

    - by yoshi
    It seems that my knetworkmanager is not starting anymore. Read: In KDE4's sys tray I don't have a icon to manage my networks. Also when starting it from terminal or kick off menu literally "nothing" happens. I don't know what's wrong with it. Sadly after reading this answer on superuser.com it seems I can not connect to wifi via iwconfig 'cause my network is WPA2 encrypted. (Basically I can not set they passphrase - invalid argumenterror.) So it seems I've to get knetworkmanger running again as I also can't download other tools. I've tried stuff like sudo service network-manager restart but it didn't seem to help. I'm kinda puzzled so any help for this would be appreciated. PS: If it hasn't become clear: The whole drama of is simply I can't connect to wifi and internet :o)

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  • Using RabbitMQ (Java client), is there a way to determine if network connection is closed during con

    - by MItch Branting
    I'm using RabbitMQ on RHEL 5.3 using the Java client. I have 2 nodes (machines). Node1 is consuming messages from a queue on Node2 using the Java helper class QueueingConsumer. QueueingConsumer consumer = new QueueingConsumer(channel); channel.basicConsume("MyQueueOnNode2", noAck, consumer); while (true) { QueueingConsumer.Delivery delivery = consumer.nextDelivery(); ... Process message - delivery.getBody() } If the interface is brought down on Node1 or Node2 (e.g. ifconfig eth1 down), the client (above) never knows the network isn't there anymore. Does RabbitMQ provide some type of configuration on the Java client that can be used to determine if the connection has gone away. Shutting down the RabbitMQ server on Node2 will trigger a ShutdownSignalException, which can be caught and the app can go into a reconnect loop. But bringing down the interface doesn't cause any type of exception to happen, so the code will be waiting forever on consumer.nextDelivery(). I've also tried using the timeout version of this call. e.g. QueueingConsumer consumer = new QueueingConsumer(channel); channel.basicConsume("MyQueueOnNode2", noAck, consumer); int timeout_ms = 30000; while (true) { QueueingConsumer.Delivery delivery = consumer.nextDelivery(timeout_ms); if (delivery == null) { if (channel.isOpen() == false) // Seems to always return true { throw new ShutdownSignalException(); } } else { ... Process message - delivery.getBody() } } but appears that this always returns true (even though the interface is down). I assume registering for the ShutdownListener on the connection will yield the same results, but haven't tried that yet. Is there a way to configure some sort of heartbeat, or do you just have to write custom lease logic (e.g. "I'm here now") in order to get this to work?

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  • Using two versions of the same assembly (system.web.mvc) at the same time

    - by Joel Abrahamsson
    I'm using a content management system whose admin interface uses MVC 1.0. I would like to build the public parts of the site using MVC 2. If I just reference System.Web.Mvc version 2 in my project the admin mode doesn't work as the reference to System.Web.Mvc.ViewPage created by the views in the admin interface is ambiguous: The type 'System.Web.Mvc.ViewPage' is ambiguous: it could come from assembly 'C:\Windows\assembly\GAC_MSIL\System.Web.Mvc\2.0.0.0__31bf3856ad364e35\System.Web.Mvc.dll' or from assembly 'C:\Windows\assembly\GAC_MSIL\System.Web.Mvc\1.0.0.0__31bf3856ad364e35\System.Web.Mvc.dll'. Please specify the assembly explicitly in the type name. I could easily work around this by using binding redirects to specify that MVC 2 should always be used. Unfortunately the content management systems admin mode isn't compatible with MVC 2. I'm not exactly sure why, but I start getting a bunch of null reference exceptions in some of it's actions when I try it and the developers of the CMS have confirmed that it isn't compatible with MVC 2 (yet). The admin interface which is accessed through domain.com/admin is not physically located in webroot/admin but in the program files folder on the server and domain.com/admin is instead routed there using a virtual path provider. Therefor, putting a separate web.config file in the admin folder to specify a different version of System.Web.Mvc for that part of the site isn't an option as that won't fly when using shared hosting. Can anyone see any solution to this problem? Perhaps it's possible to specify that for some assemblies a different version of a referenced assembly should be used?

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  • How to achieve "Blendability" when using DataServiceCollection in my ViewModel

    - by andlju
    I'm looking at using oData endpoints in my Silverlight client. Naturally, I'm doing MVVM and I want the project to be nice and "Blendable" (i.e. I must be able to cleanly use static data instead of the oData endpoints when in design mode.) Now to the problem. I'd like to use the DataServiceCollection in my ViewModels, since it allows for nice bindable collections without having to worry too much with BeginExecute/EndExecute etc. Now, let's look at some code. My Model interface looks like this: public interface ITasksModel { IQueryable<Task> Tasks { get; } } The oData endpoint implementation of that interface: public class TasksModel : ITasksModel { Uri svcUri = new Uri("http://localhost:2404/Services/TasksDataService.svc"); TaskModelContainer _container; public TasksModel() { _container = new TaskModelContainer(svcUri); } public IQueryable<Task> Tasks { get { return _container.TaskSet; } } } And the "Blendable" design-time implementation: public class DesignModeTasksModel : ITasksModel { private List<Task> _taskCollection = new List<Task>(); public DesignModeTasksModel() { _taskCollection.Add(new Task() { Id = 1, Title = "Task 1" }); _taskCollection.Add(new Task() { Id = 2, Title = "Task 2" }); _taskCollection.Add(new Task() { Id = 3, Title = "Task 3" }); } public IQueryable<Task> Tasks { get { return _taskCollection.AsQueryable(); } } } However, when I try to use this last one in my ViewModel constructor: public TaskListViewModel(ITasksModel tasksModel) { _tasksModel = tasksModel; _tasks = new DataServiceCollection<Task>(); _tasks.LoadAsync(_tasksModel.Tasks); } I get an exception: Only a typed DataServiceQuery object can be supplied when calling the LoadAsync method on DataServiceCollection. First of all, if this is the case, why not make the input parameter of LoadAsync be typed as DataServiceQuery? Second, what is the "proper" way of doing what I'm trying to accomplish?

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  • shouldAutorotateToInterfaceOrientation called several times in a row without any rotation

    - by Mike
    I am trying to implement some interface changes in my app, based on the device rotation. My app is a view based app. So, its main view controller has a didload method. The app starts in portrait. Almost all changes on the device orientation triggers the shouldAutorotateToInterfaceOrientation method but this method is not called when the device is put on portrait, after coming from any landscape orientation. While debugging the app, I have put a NSLog(@"orientation=%d", interfaceOrientation); on my shouldAutorotateToInterfaceOrientation method, and what I see is quite strange: When I run the app, shouldAutorotateToInterfaceOrientation is called 6 times before the app's interface even appears. Every time it runs, it reports a different number for the orientation: the order it reports on console is: portrait, portrait, portrait, landscape right, landscape left, upside down) (????). During this time the app is just beginning. All 6 times the debugger reports the method being run by the app's delegate. So, here comes the questions: WHy shouldAutorotateToInterfaceOrientation is not being called when the device enters on portrait? Why is this method running 6 times called by the delegate even before the app starts and shows its interface if no rotation is being done? thanks.

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  • handling refrence to pointers/double pointers using SWIG [C++ to Java]

    - by Siddu
    My code has an interface like class IExample { ~IExample(); //pure virtual methods ...}; a class inheriting the interface like class CExample : public IExample { protected: CExample(); //implementation of pure virtual methods ... }; and a global function to create object of this class - createExample( IExample *& obj ) { obj = new CExample(); } ; Now, I am trying to get Java API wrapper using SWIG, the SWIG generated interface has a construcotr like - IExample(long cPtr, boolean cMemoryOwn) and global function becomes createExample(IExample obj ) The problem is when i do, IExample exObject = new IExample(LogFileLibraryJNI.new_plong(), true /*or false*/ ); createExample( exObject ); The createExample(...) API at C++ layer succesfully gets called, however, when call returns to Java layer, the cPtr (long) variable does not get updated. Ideally, this variable should contain address of CExample object. I read in documentation that typemaps can be used to handle output parameters and pointer references as well; however, I am not able to figure out the suitable way to use typemaps to resolve this problem, or any other workaround. Please suggest if i am doing something wrong, or how to use typemap in such situation?

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  • WCF deadlock when using callback channel

    - by mafutrct
    This is probably a simple mistake, but I could not figure out what was wrong. I basically got a method like this: [ServiceBehavior ( ConcurrencyMode = ConcurrencyMode.Reentrant, InstanceContextMode = InstanceContextMode.PerSession, IncludeExceptionDetailInFaults = true) ] public class Impl : SomeContract { public string Foo() { _CallbackChannel.Blah(); return ""; } } Its interface is decorated: [ServiceContract ( Namespace = "http://MyServiceInterface", SessionMode = SessionMode.Required, CallbackContract = typeof (WcfCallbackContract)) ] public interface SomeContract { [OperationContract] string Foo (); } The service is hosted like this: ServiceHost host = new ServiceHost (typeof (Impl)); var binding = new NetTcpBinding (); var address = new Uri ("net.tcp://localhost:8000/"); host.AddServiceEndpoint ( typeof (SomeContract), binding, address); host.Open (); The client implements the callback interface and calls Foo. Foo runs, calls the callback method and returns. However, the client is still struck in the call to Foo and never returns. The client callback method is never run. I guess I made a design mistake somewhere. If needed, I can post more code. Any help is appreciated.

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