Windows C++ Get CPU and Memory Utilisation With Performance Counters

Aim
The aim of this example is to create a simple program that will display CPU and memory uisng PDH Performance Counters. We will be using the windows command line compiler cl.exe that comes with Visual Studio C++ for this example. Leave any questions or problems as comments and I will endeavour to answer them.

Assumptions
This article assumes that you have VC++ installed and configured. See Problems and Solutions Installing VC++ Express Edition, to install and run vcvars32.bat.

Versions used in this example
Sofware/Component
Image
Windows XP SP2
N/A
Visual Studio Express Editions 2008 VC++
N/A
Links to these files can be found here


Write and compile the application
  1. While you can get Memory status fairly easlily with GlobalMemoryStatusEx, there is no equivalent function for CPU. Therefore you have to use PDH Performance Counter Interface to get CPU utilisation. Write the application and save is as check.cpp.

    Also note that CPU is a difference between two PdhCollectQueryData calls, so if you call this once and try to get PdhGetFormattedCounterValue you will get an error.

     1. #include <iostream>
 2. #include <windows.h>
 3. #include <stdio.h>
 4. #include <pdh.h>
 5. #include <pdhmsg.h>
 6. 
 7. #define KB 1024
 8. void main(int argc, char *argv[]){
 9. 
10.     PDH_HQUERY hquery;
11.     PDH_HCOUNTER hcountercpu;
12.     PDH_HCOUNTER hcounterram;
13.     PDH_STATUS status;
14.     LPSTR pMessage;
15.     PDH_FMT_COUNTERVALUE countervalcpu;
16.     PDH_FMT_COUNTERVALUE countervalram;
17.     MEMORYSTATUSEX memstat;
18.     
19.     memstat.dwLength = sizeof (memstat);
20. 
21.     if((status=PdhOpenQuery(NULL, 0, &hquery))!=ERROR_SUCCESS){
22.         printf("PdhOpenQuery %lx\n", status);    
23.         goto END;
24.     }
25. 
26.     if((status=PdhAddCounter(hquery,
27.                             "\\Processor(_Total)\\% Processor Time",
28.                             0, 
29.                             &hcountercpu))!=ERROR_SUCCESS){
30.         printf("PdhAddCounter (cpu) %lx\n", status);    
31.         goto END;
32.     }
33.     if((status=PdhAddCounter(hquery,
34.                             "\\Memory\\Available Bytes",
35.                             0, 
36.                             &hcounterram))!=ERROR_SUCCESS){
37.         printf("PdhAddCounter (ram) %lx\n", status);    
38.         goto END;
39.     }
40.     
41.     /*Start outside the loop as CPU requires difference 
42.     between two PdhCollectQueryData s*/
43.     if((status=PdhCollectQueryData(hquery))!=ERROR_SUCCESS){
44.         printf("PdhCollectQueryData %lx\n", status);    
45.         goto END;
46.     }
47. 
48.     while(true){
49. 
50.         if((status=PdhCollectQueryData(hquery))!=ERROR_SUCCESS){
51.             printf("PdhCollectQueryData %lx\n", status);    
52.             goto END;
53.         }
54.         if(GlobalMemoryStatusEx(&memstat)==0){
55.             printf("GlobalMemoryStatusEx %d\n", GetLastError());
56.             goto END;
57.         }
58. 
59.         if((status=PdhGetFormattedCounterValue(hcountercpu, 
60.                                                 PDH_FMT_LONG, 
61.                                                 0, 
62.                                                 &countervalcpu))!=ERROR_SUCCESS){
63.             printf("PdhGetFormattedCounterValue(cpu) %lx\n", status);    
64.             goto END;
65.         }
66.         if((status=PdhGetFormattedCounterValue(hcounterram, 
67.                                                 PDH_FMT_LONG, 
68.                                                 0, 
69.                                                 &countervalram))!=ERROR_SUCCESS){
70.             printf("PdhGetFormattedCounterValue(ram) %lx\n", status);    
71.             goto END;
72.         }
73.         printf("cpu %3d%% \tmem %3d%% \tavail (%d mb)\n", 
74.             countervalcpu.longValue, 
75.             memstat.dwMemoryLoad, 
76.             countervalram.longValue/(KB*KB));
77. 
78.         Sleep(1000);
79. 
80.     }
81. END:
82.     ;
83. }
    Hide line numbers

  2. Open a prompt to the working directory and compile the code using the windows cl.exe compiler. You just need to include the pdh.lib.

    ..workspace\PerfCounter>cl check.cpp pdf.lib

  3. Now run the program in the command prompt. You should see the cpu and memory snapshot displayed every second.
4 comments

Weblogic MBean Example (ExecuteQueueRuntime)

Aim
The aim of this tutorial is to connect to a Weblogic MBean from a remote client and extract some Information We will be connecting to the ExecuteQueueRuntime Mbean and getting the idle thread count . Leave any questions or problems as comments and I will endeavour to answer them.

Assumptions
This article assumes that you have a compatible version of Weblogic installed and running and you have a compatible version of the JDK aswell.

Versions used in this example
Sofware/ComponentImage
Weblogic Server 8.1N/A
JDK 1.4.2N/A
Links to these files can be found here

In the source file you are connecting to the admin port on weblogic.

Please make sure the the java versions on your weblogic server and the java version on the client machine are the same or else you will get incompatible serialVersionUID errors like the ones below.

<9/09/2009 01:22:39 PM EST> <Error> <RJVM> <BEA-000503> <Incoming message header or abbreviation processing failed java.io.InvalidClassException: javax.management.ObjectName; local class incompatible: stream classdesc serialVersionUID = -5467795090068647408, local class serialVersionUID = 1081892073854801359
.....

>


Write and Compile the Example
  1. Write the client code and save it as WeblogicMBeanExample.java in your working directory. Make sure you edit the url, username and password to match your system. The url is basically your weblogic admin url. 
     1. import java.util.*;
 2. import java.rmi.RemoteException;
 3. import javax.naming.*;
 4. import java.io.*;
 5. 
 6. import weblogic.jndi.Environment;
 7. import weblogic.management.MBeanHome;
 8. import javax.management.ObjectName;
 9. import weblogic.management.runtime.ExecuteQueueRuntimeMBean;
10. 
11. public class WeblogicMBeanExample{
12.     
13.     public static void main(String[] args){
14.         new WeblogicMBeanExample().GoBeans();
15.     }
16. 
17.     public void GoBeans(){
18.         MBeanHome home;
19.         String url = "t3://myhost:7001";
20.         String username = "weblogic";
21.         String password = "password123";
22. 
23.         ExecuteQueueRuntimeMBean mbeanExecuteQueueRuntime;
24.         Set mbeanSet;
25.         Iterator mbeanIterator;
26. 
27.         try{
28.             Properties prop = new Properties();
29.             prop.put(Context.INITIAL_CONTEXT_FACTORY, 
30.                 "weblogic.jndi.WLInitialContextFactory");
31.             prop.put(Context.PROVIDER_URL, url);
32.             prop.put(Context.SECURITY_PRINCIPAL, username);
33.             prop.put(Context.SECURITY_CREDENTIALS, password);
34.         
35.             Context ctx = new InitialContext(prop);
36.             home = (MBeanHome) ctx.lookup(MBeanHome.ADMIN_JNDI_NAME);
37.             mbeanSet = home.getMBeansByType("ExecuteQueueRuntime");
38.             mbeanIterator = mbeanSet.iterator();
39. 
40.             while(mbeanIterator.hasNext()){
41.                 mbeanExecuteQueueRuntime = 
42.                                 (ExecuteQueueRuntimeMBean)mbeanIterator.next();
43.                 ShowInfo(mbeanExecuteQueueRuntime);
44.             }
45.         }catch (Exception e){
46.             e.printStackTrace();
47.         }
48.         
49.     }
50.     
51.     static void ShowInfo(ExecuteQueueRuntimeMBean meqr){
52.         try{
53.             System.out.print(meqr.getName());
54.             System.out.print("\t\t"+meqr.getExecuteThreadCurrentIdleCount());
55.             System.out.print("\t\t"+meqr.getParent().getName());
56.         }catch(Exception e){
57.             System.out.print("\t\tError");
58.             e.printStackTrace();
59.         }
60.         finally{
61.             System.out.println("\n");
62.         }
63.     }
64. }
    Hide line numbers

  2. You need the weblogic.jar to compile this. I strongly suggest you take a copy of the weblogic.jar file from the weblogic server you are trying to connect to. This will limit any incompatibility issues. Copy the weblogic.jar file to your working directory. It should be with your source file.

  3. Now open a promt to where you saved the file and compile it.

    javac -classpath .;weblogic.jar WeblogicMBeanExample.java

  4. Now run it.

    java -cp .;weblogic.jar WeblogicMBeanExample
2 comments
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