[Version 5.0.1 and later]Using the Runtime Performance Advisor

Why and when to perform this task

The Runtime Performance Advisor provides advice to help tune systems for optimal performance and is configured using the WebSphere Application Server administrative console or the wsadmin tool . The Runtime Performance Advisor uses Performance Monitoring Infrastructure (PMI) data to provide recommendations for performance tuning. Running in the JVM of the application server, this advisor periodically checks for inefficient settings, and issues recommendations as standard product warning messages. These recommendations are displayed both as warnings in the administrative console under WebSphere Runtime Messages in the WebSphere Status panel and as text in the application server SystemOut.log file. Enabling the Runtime Performance Advisor has minimal system performance impact.

Steps for this task

  1. Enable PMI services in the application server as described in Enabling performance monitoring services in the application server through the administrative console.
    In order to obtain advice, you must first enable the performance monitoring service through the administrative console and restart the server. The Runtime Performance Advisor enables the appropriate monitoring counter levels for all enabled advice. If there are specific counters that are not wanted, disable the corresponding advice in the Runtime Performance Advisor Panel, and disable unwanted counters. If there are specific counters that are not wanted, or when disabling the Runtime Performance Advisor, the user may want to disable the PMI Service or the counters that RPA enabled.
  2. Start the administrative console at described in Starting and stopping the administrative console.
  3. Click Servers > Application Servers in the console navigation tree.
  4. Click server_name > Runtime Performance Advisor Configuration.
  5. Click the Configuration tab.
  6. Select the Number of Processors.
    Select the appropriate settings for your system configuration to ensure accurate advice.
  7. Select the Calculation Interval.
    PMI data is taken over an interval of time and averaged to provide advice. The calculation 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.
  8. 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 only issued if the rate of discards exceeds the new threshold setting.
  9. Click Apply.
  10. Click Save.
  11. Click the Runtime tab.
  12. Click Restart.
    Selecting Restart on the Runtime tab reinitializes the Runtime Performance Advisor using the last configuration information saved to disk.

    Note: This action also resets the state of the Runtime Performance Advisor. For example, the current warning count is reset to zero for each message.

  13. 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. The Runtime Performance Advisor only provides advice when CPU utilization exceeds a sufficiently high level. For a list of IBM business partners providing tools to drive this type of load, see the article, Performance: Resources for learning in the sub-section of Monitoring performance with third party tools.
  14. Select the check box to enable the Runtime Performance Advisor.

    Note: To achieve the best results for performance tuning, enable the Runtime Performance Advisor when a stable production level load is being applied.

  15. Click OK.
  16. Select Warnings in the administrative console under the WebSphere Runtime Messages in the WebSphere Status panel or look in the SystemOut.log file, located in the install_root\logs\servername directory to view tuning advice. Some messages are not issued immediately.
  17. Update the product configuration for improved performance, based on advice.
    Although the performance advisors attempt to distinguish between loaded and idle conditions, misleading advice might be issued if the advisor is enabled while the system is ramping up or down. 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 ensure it functions and performs well.

    Over a period of time the advisor may issue differing advice. This is due to load fluctuations and runtime state. When differing advice is received the user should look at all advice and the time period over which it was issued. Advice should be taken during the time that most closely represents peak production load.

    Performance tuning is an iterative process. After applying advice, simulate a production load, update the configuration based on the advice, and retest for improved performance. This procedure should be continued until optimal performance is achieved.

What to do next

WebSphere Application Server also allows you to enable and disable advice in the Advice Configuration panel. 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 on Advice configuration, see the article, Advice configuration settings

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Related concepts
Performance Monitoring Infrastructure
Related tasks
Using the Performance Advisor in Tivoli Performance Viewer
Related reference
Runtime Performance Advisor configuration settings
Advice configuration settings
Performance: Resources for learning



Searchable topic ID:   tprf_enpadvice
Last updated: Jun 21, 2007 8:07:48 PM CDT    WebSphere Business Integration Server Foundation, Version 5.0.2
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