How to use IIS Manager to get Worker Processes (w3wp.exe) details information ?

In one of my previous blog post, Identifying Worker Process (w3wp.exe) – IIS 6.0 and IIS 7.0 for Debugging ASP.NET Application  -  I have explained about how we can identify the list of currently running worker process  using command prompt while we need to attach process from visual studio . But do you know for IIS 7.0 and IIS 7.5 we can get the worker process (w3wp.exe) details like Application Pool name, Process ID, CPU Usages from IIS Manager itself. Even you can get details of each worker process for a “Web Garden” scenarios.  So when you need to attach some process for debugging from Visual studio, Instead of going to command prompt, you can easily identify the worker process Id from IIS itself.  

Get Worker Processes ( w3wp.exe) List :

To get list of running  worker process, Open IIS Manager ( Run > Inetmgr ), Select root level from left site navigation tree and from “Features View Panel” select “Worker Processes”

Click on the “Worker Processes” to get details of all worker process which are currently running as shown in below.

So from the above list of worker processes you can get the details of Application Pool Name, Process ID, state of worker processes along with CPU uses and memory uses.

Attach Worker Processes (w3wp.exe) For Debugging  :

From Visual studio Attach Process window you will find the same list of worker process with the same Process ID. So based on your application Pool name you can attach the process and start the debugging.

To Know more about attach process while debugging your application is running on IIS,  please read one of my complete article -  Debug Your ASP.NET Application that Hosted on IIS : Process Attach and Identify which process to attach ( Note: This article was targeted to debugging with IIS 6.0 )

What else we can have from Worker Processes lists in IIS 7 Manager?

We have already identified the worker process  and Application Pool name which are more than enough for us to attach a process from Visual Studio. Now what else we can get out of this list ? Yes we can have enough information regarding worker process like

• Worker Process Current State
• CPU Uses by the worker process
• Memory uses by worker process
• Current Request Handling by Worker Process

What about the current Worker Process (w3wp.exe ) State  ?

You can get the current status of worker process from status column. Worker processes having 3 status as listed below

1. Running
2. Stopping
3. Starting

 
You must be wondering why there is no  “Stopped” Status for Worker Process in IIS ?  I will explorer it in a different blog post. Yeah that will be very interesting ! Very soon !
Similar like State you can also monitor CPU % Uses and  Memory Uses from the IIS Itself.

What about the Current  Request  at Worker Process ?

Well, you can view the current request details for a particular worker process from IIS Manager Itself. So, When your worker process is on running mode, If you want to check the what are the thing going on backend, just double click on the particular worker process.

From the request details, you can get web site id, URL, HTTP Verbs, client ID and State along with Module Name. I liked the State and  Module name column very much. This two columns will let you know where is your current request and which HTTP Module is taking care of that Request.
To know more about how fundamentals How IIS process ASP.NET Request you can read one of my article How IIS Process ASP.NET Request
You can also read  “Securely Implement Request Processing, Filtering, and Content Redirection with HTTP Pipelines in ASP.NET” to know more advance topics.
To know more about Worker Process Request read View Currently Executing Requests in a Worker Process (IIS 7)

View Details of Each Worker Process when you are using Web Garden

Before start web garden mode, if you want to know more about Web garden or just wanted to recap please read on of my previous article  What is the difference between Web Farm and Web Garden ?  
If You have configured  your site as Web Garden, you can also get the list of all the worker process in the worker processes list with the  different worker Process ID  but all worker process should have a “Single Application Pool “ .
 
So, from the above diagrams you can see, “WCFSite” has configured as  Web Garden mode with Two Worker Process and from the Worker Processes list you can view both the worker process with different Worker Process Id and both of them are listed under  same Application Pool.
Note: You will able to see only the worker process which are in running state .
Summary : In this blog post I have explained how you can use the power of IIS Manager to get the list of worker process with there application pool id, name, Running State along with CPU and Memory Uses along with viewing the worker process request. I have also explained about how to  get details of each worker process in web garden scenarios. I will publish another blog post  Worker Process State very soon.
Hope this will help !
Thanks !

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Beginner’s Guide: How IIS Process ASP.NET Request

Introduction

When request come from client to the server a lot of operation is performed before sending response to the client. This is all about how IIS Process the request.  Here I am not going to describe the Page Life Cycle and there events, this article is all about the operation of IIS Level.  Before we start with the actual details, let’s start from the beginning so that each and everyone understand it’s details easily.  Please provide your valuable feedback and suggestion to improve this article.

What is Web Server ?

When we run our ASP.NET Web Application from visual studio IDE, VS Integrated ASP.NET Engine is responsible to execute all kind of asp.net requests and responses.  The process name is “WebDev.WebServer.Exe” which actually takw care of all request and response of an web application which is running from Visual Studio IDE.
Now, the name “Web Server” comes into picture when we want to host the application on a centralized location and wanted to access from many locations. Web server is responsible for handle all the requests that are coming from clients, process them and provide the responses.

What is IIS ?

IIS (Internet Information Server) is one of the most powerful web servers from Microsoft that is used to host your ASP.NET Web application. IIS has it’s own ASP.NET Process Engine  to handle the ASP.NET request. So, when a request comes from client to server, IIS takes that request and  process it and send response back to clients.

Request Processing :

Hope, till now it’s clear to you that what is Web server and IIS is and what is the use of them. Now let’s have a look how they do things internally. Before we move ahead, you have to know about two main concepts
1.    Worker Process
2.   Application Pool
Worker Process:  Worker Process (w3wp.exe) runs the ASP.Net application in IIS. This process is responsible to manage all the request and response that are coming from client system.  All the ASP.Net functionality runs under the scope of worker process.  When a request comes to the server from a client worker process is responsible to generate the request and response. In a single word we can say worker process is the heart of ASP.NET Web Application which runs on IIS.
Application Pool: Application pool is the container of worker process.  Application pools is used to separate sets of IIS worker processes that share the same configuration.  Application pools enables a better security, reliability, and availability for any web application.  The worker process serves as the process boundary that separates each application pool so that when one worker process or application is having an issue or recycles, other applications or worker processes are not affected. This makes sure that a particular web application doesn’t not impact other web application as they they are configured into different application pools.

Application Pool with multiple worker process is called “Web Garden”.
Now, I have covered all the basic stuff like Web server, Application Pool, Worker process. Now let’s have look how IIS process the request when a new request comes up from client.
If we look into the IIS 6.0 Architecture, we can divided them into Two Layer

1.    Kernel Mode
2.    User Mode

Now, Kernel mode is introduced with IIS 6.0, which contains the HTTP.SYS.  So whenever a request comes from Client to Server, it will hit HTTP.SYS First.

Now, HTTP.SYS is Responsible for pass the request to particular Application pool. Now here is one question, How HTTP.SYS comes to know where to send the request?  This is not a random pickup. Whenever we creates a new Application Pool, the ID of the Application Pool is being generated and it’s registered with the HTTP.SYS. So whenever HTTP.SYS Received the request from any web application, it checks for the Application Pool and based on the application pool it send the request.

So, this was the first steps of IIS Request Processing.
Till now, Client Requested for some information and request came to the Kernel level of IIS means at HTTP.SYS. HTTP.SYS has been identified the name of the application pool where to send. Now, let’s see how this request moves from HTTP.SYS to Application Pool.
In User Level of IIS, we have Web Admin Services (WAS) which takes the request from HTTP.SYS and pass it to the respective application pool.

When Application pool receive the request, it simply pass the request to worker process (w3wp.exe) . The worker process “w3wp.exe” looks up the URL of the request in order to load the correct ISAPI extension. ISAPI extensions are the IIS way to handle requests for different resources. Once ASP.NET is installed, it installs its own ISAPI extension (aspnet_isapi.dll) and adds the mapping into IIS.
Note : Sometimes if we install IIS after installing asp.net, we need to register the extension with IIS using aspnet_regiis command.

When Worker process loads the aspnet_isapi.dll, it start an HTTPRuntime, which is the entry point of an application. HTTPRuntime is a class which calls the ProcessRequest method to start Processing.

When this methods called, a new instance of HTTPContext is been created.  Which is accessible using HTTPContext.Current  Properties. This object still remains alive during life time of object request.  Using HttpContext.Current we can access some other objects like Request, Response, Session etc.

After that HttpRuntime load an HttpApplication object with the help of  HttpApplicationFactory class.. Each and every request should pass through the corresponding HTTPModule to reach to HTTPHandler, this list of module are configured by the HTTPApplication.
Now, the concept comes called “HTTPPipeline”. It is called a pipeline because it contains a set of HttpModules ( For Both Web.config and Machine.config level) that intercept the request on its way to the HttpHandler. HTTPModules are classes that have access to the incoming request. We can also create our own HTTPModule if we need to handle anything during upcoming request and response.

HTTP Handlers are the endpoints in the HTTP pipeline. All request that are passing through the HTTPModule should reached to HTTPHandler.  Then  HTTP Handler  generates the output for the requested resource. So, when we requesting for any aspx web pages,   it returns the corresponding HTML output.
All the request now passes from  httpModule to  respective HTTPHandler then method and the ASP.NET Page life cycle starts.  This ends the IIS Request processing and start the ASP.NET Page Lifecycle.

Conclusion

When client request for some information from a web server, request first reaches to HTTP.SYS of IIS. HTTP.SYS then send the request to respective  Application Pool. Application Pool then forward the request to worker process to load the ISAPI Extension which will create an HTTPRuntime Object to Process the request via HTTPModule and HTTPHanlder. After that the ASP.NET Page LifeCycle events starts.
This was just overview of IIS Request Processing to let Beginner’s know how the request get processed in backend.  If you want to learn in details please check the link for Reference and further Study section.

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