Use the Runtime Performance Advisor

The Runtime Performance Advisor provides advice to help tune systems for optimal performance. The Runtime Performance Advisor uses Performance Monitoring Infrastructure (PMI) data to provide recommendations for performance tuning. For more information about PMI, see Performance Monitoring Infrastructure (PMI).

This advisor runs in the JVM of the application server, and periodically checks for inefficient settings. Recommendations are provided in the form of standard product warning messages. These recommendations are displayed both as warnings in the administrative console under WebSphere Runtime Messages and as text in the application server SystemOut.log file. The Runtime Performance Advisor has minimal system performance impact.

For more information about configuration settings for the Runtime Performance Advisor, see Runtime Performance Advisor configuration settings.

The Runtime Performance Advisor enables the appropriate monitoring counter levels for all enabled advice. If there are specific counters that you do not want to monitor, disable the corresponding advice in the Runtime Performance Advisor, and disable unwanted counters.

Note: Before you enable the Runtime Performance Advisor, Enable performance monitoring services for an application server and restart the application server. For WebSphere Application Server Network Deployment, enable performance monitoring services for a node agent and restart the node agent.

To use the Runtime Performance Advisor, follow these steps:

1. Start the administrative console.

2. In the administrative console topology tree, expand Servers and click Application Servers.

3. Click the name of the server for which you want to configure the Runtime Performance Advisor.

4. Click Runtime Performance Advisor Configuration.

5. On the Configuration tab, configure these settings:

   • Select the Calculation Interval. PMI data is taken over an interval of time and averaged to provide advice. The interval specifies the length of the time over which data is taken for this advice. Therefore, details within the advice messages appear as averages over this interval.
   • Select the Maximum Warning Sequence. The maximum warning sequence refers to the number of consecutive warnings issued before the threshold is updated. For example, if the maximum warning sequence is set to 3, then the advisor only sends three warnings to indicate that the prepared statement cache is overflowing. After that, a new alert is sent only if the rate of discards exceeds the new threshold setting.
   • Specify Number of Processors. Select the appropriate settings for your system configuration to ensure accurate advice.

     Note: A limited number of values is available. If the number of processors in your WebSphere Application Server partition is not listed, select the next highest number.

6. Click Apply.

7. Save the configuration.

8. In the administrative console topology tree, expand Servers and click Application Servers.

9. Click the name of the server for which you want to configure the Runtime Performance Advisor.

10. Click Runtime Performance Advisor Configuration.

11. Click the Runtime tab.

12. On the Runtime tab, configure these settings:

    • Select the Calculation Interval. PMI data is taken over an interval of time and averaged to provide advice. The interval specifies the length of the time over which data is taken for this advice. Therefore, details within the advice messages appear as averages over this interval.
    • Select the Maximum Warning Sequence. The maximum warning sequence refers to the number of consecutive warnings issued before the threshold is updated. For example, if the maximum warning sequence is set to 3, then the advisor only sends three warnings to indicate that the prepared statement cache is overflowing. After that, a new alert is sent only if the rate of discards exceeds the new threshold setting.
    • Specify Number of Processors. Select the appropriate settings for your system configuration to ensure accurate advice.

      Note: A limited number of values is available. If the number of processors in your WebSphere Application Server partition is not listed, select the next highest number.

13. Click OK.

14. Click Restart on the Runtime tab to reinitialize the Runtime Performance Advisor based on the most recent saved configuration. This action also resets the state of the Runtime Performance Advisor. For example, the current warning count is reset to zero for each message.

15. Simulate a production level load. If you are using the Runtime Performance Advisor in a test environment, or doing any other tuning for performance, simulate a realistic production load for your application. The application should run this load without errors. This simulation includes numbers of concurrent users typical of peak periods, and drives system resources, such as CPU and memory to the levels expected in production. Some advice may not be accurate if sufficient load is not generated.

16. Select the check box to enable the Runtime Performance Advisor to achieve the best results for performance tuning, when a stable production level load is being applied.

17. Click OK.

18. Use one of these options to view tuning advice:

    • In the administrative console, select Warnings under the WebSphere Runtime Messages in the WebSphere Status panel.
    • View the SystemOut.log file. This file is located in the /QIBM/UserData/WebAS5/Base/instance_name/logs/server_name directory.

    Note: Some messages are not issued immediately.

19. Update the product configuration for improved performance, based on advice. Although the performance advisors attempt to distinguish between loaded and idle conditions, the advisor might provide misleading advice if it is enabled when the system is not in one of those states. This result is especially likely when running short tests. Although the advice helps in most configurations, there might be situations where the advice hinders performance. Due to these conditions, advice is not guaranteed. Therefore, test the environment with the updated configuration to verify that it functions and performs well.

You can also enable and disable advice on the Advice Configuration page. Some advice applies only to certain configurations, and can only be enabled for those configurations. For example, Unbounded ORB Service Thread Pool advice is only relevant when the ORB Service thread pool is unbounded, and can only be enabled when the ORB thread pool is unbounded. For more information about advice configuration, see Advice configuration settings.