Using the Runtime Performance Advisor
In order to obtain advice, first enable the performance monitoring service through the Administrative Console and restart the server. If running Network Deployment, enable the 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. See Enabling the PMI service for details. Then do the following:
1. In the WebSphere Administrative Console select Servers -> Application Servers from the navigation tree. 2. Click <server_name> -> Runtime Performance Advisor Configuration. 3. On the Configuration tab select the Number of Processors. Selecting the appropriate settings for the system's configuration ensures accurate performance advice.
4. Optionally, select the Calculation Interval. 5. Again optionally, select the Maximum warning sequence. 6. Click Apply and Save your changes. 7. Select the Runtime tab and click Restart. 8. Simulate a production level load. For load testing tools and how to perform the load testing, see 19.2, Tools of the trade.
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 the number of concurrent users typical for 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.
9. Once a stable production level load is reached, select the check box to Enable the Runtime Performance Advisor. This way, you will achieve the best results for performance tuning. Click OK. 10. Select Warnings in the Administrative Console under the WebSphere Runtime Messages in the WebSphere Status panel or look at the SystemOut.log file, located in the <install_root\logs\server_name> directory to view tuning advice. Some messages are not issued immediately. 11. Update the product configuration for improved performance, based on the received advice.
Important: As with any analysis and tuning, make sure that only one parameter is changed, and then the results monitored. This provides an effective method of backing out of the change if it proves detrimental to the environment. Also, making multiple changes could result in undesired results, because many options are dependent on other settings.
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 as expected.
Tips for using the Runtime Performance Advisor:
Enable Performance Monitoring Service in the appserver and in the Node Agent if running Network Deployment. Be sure to configure the correct number of processors. Simulate a production level load. Ensure the application runs without exceptions/errors. Runtime Performance Advisor only provides advice when CPU utilization is high. Once production load level is reached, enable the Runtime Performance Advisor. Apply advice, restart the appserver, and re-test. More details can be found in the WebSphere InfoCenter section "Using the Runtime Performance Advisor".