Use the Runtime Performance Advisor

 

The Runtime Performance Advisor provides advice to help tune systems for optimal performance and is configured using the WAS administrative console. The Runtime Performance Advisor uses Performance Monitoring Infrastructure (PMI) data to provide recommendations for performance tuning. Running in the JVM of the appserver, 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.

  1. Enable PMI services in WAS , and Enable PMI services in NodeAgent if running WAS Network Deployment.In order to obtain advice, first enable the performance monitoring service through the administrative console and restart the server. If running Network Deployment, enable PMI service on both the server and on the node agent and restart the server and node agent. 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. Go to...

    Administrative console Servers | Application Servers | server | Runtime Performance Advisor Configuration | Configuration

  3. Select the Number of Processors.

    Select the appropriate settings for your system configuration to ensure accurate advice.

  4. 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.

  5. 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.

  6. Click Apply.

  7. Click Save.

  8. Click the Runtime tab.

  9. Click Restart.Selecting Restart on the Runtime tab reinitializes the Runtime Performance Advisor using the last configuration information saved to disk.

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

  10. 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.

  11. Select the check box to enable the Runtime Performance Advisor.

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

  12. Click OK.

  13. 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 $WAS_HOME\logs\servername directory to view tuning advice. Some messages are not issued immediately.

  14. 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.

WAS 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.

 

Runtime Performance Advisor configuration settings

Use this page to specify settings for the Runtime Performance Advisor.

For more information on how to use the Runtime Performance Advisor, see Using the Runtime Performance Advisor.

To view this administrative page, click Servers > Application Servers > server > Runtime Performance Advisor Configuration.

 

Configuration tab

Enable Runtime Performance Advisor Specifies whether the Runtime Performance Advisor will run on server startup.

The Runtime Performance Advisor (RPA) requires that the Performance Monitoring Service be enabled. It does not require that individual counters be enabled. When a counter that is needed by RPA is not enabled, RPA will enable it automatically. When disabling the Runtime Performance Advisor the user may want to disable the PMI Service or the counters that RPA enabled. The following counters may be enabled by RPA:

  • ThreadPools (module)

    • Web Container (module)

      • Pool Size

      • Active Threads

    • Object Request Broker (module)

      • Pool Size

      • Active Threads

  • JDBC Connection Pools (module)

    • Pool Size

    • Percent used

    • Prepared Statement Discards

  • Servlet Session Manager (module)

    • External Read Size

    • External Write Size

    • External Read Time

    • External Write Time

    • No Room For New Session

  • System Data (module)

    • CPU Utilization

    • Free Memory

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. Details within the advice messages will appear as averages over this interval.

Maximum warning sequence The maximum warning sequence refers to the number of consecutive warnings issued before the threshold is relaxed.

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.

Number of processors Specifies the number of processors on the server.

This setting is critical to ensure accurate advice for the system's specific configuration.

Runtime tab

Enable Runtime Performance Advisor Starts the Runtime Performance Advisor on the current server.

The Runtime Performance Advisor (RPA) requires that the Performance Monitoring Service be enabled. It does not require that individual counters be enabled. When a counter that is needed by RPA is not enabled, RPA will enable it automatically. When disabling the Runtime Performance Advisor the user may want to disable the PMI Service or the counters that RPA enabled. The following counters may be enabled by RPA:

  • ThreadPools (module)

    • Web Container (module)

      • Pool Size

      • Active Threads

    • Object Request Broker (module)

      • Pool Size

      • Active Threads

  • JDBC Connection Pools (module)

    • Pool Size

    • Percent used

    • Prepared Statement Discards

  • Servlet Session Manager (module)

    • External Read Size

    • External Write Size

    • External Read Time

    • External Write Time

    • No Room For New Session

  • System Data (module)

    • CPU Utilization

    • Free Memory

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. Details within the advice messages will appear as averages over this interval.

Maximum warning sequence The maximum warning sequence refers to the number of consecutive warnings issued before the threshold is relaxed.

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.

Number of processors Specifies the number of processors on the server.

This setting is critical to ensure accurate advice for the system's specific configuration.

Restart button Selecting Restart on the Runtime tab reinitializes the Runtime Performance Advisor using the last information saved to disk. Note that this action also resets the state of the Runtime Performance Advisor. For example, the current warning sequence is reset to zero for each recommendation/advice.

 

See Also

PMI
Using the Performance Advisor in Tivoli Performance Viewer
Runtime Performance Advisor configuration settings
Advice configuration settings
Administrative console buttons
Administrative console scope settings
Administrative console filter settings
Administrative console preference settings