6.4.  Use Tivoli Performance Viewer (TPV) / Request Metrics to gather information about resources and analyze results.


Tivoli performance viewer

Tivoli Performance Viewer (TPV) is included with WebSphere Application Server V7.0 and is used to record and display performance data. Since WebSphere Application Server V6.0, TPV is integrated into the Integrated Solutions Console.

Using Tivoli Performance Viewer, you can perform the following tasks:

You can use TPV to create summary reports. These reports let you monitor the server's real-time performance and health. TPV enables you to work with the performance modules. With these modules, you can drill down on specific areas of interest, even old logs. Use the log analysis tools to detect trends over time. TPV can also save performance data for later analysis or problem determination.

As the TPV runs inside the Integrated Solutions Console, the performance impact depends on which edition of WebSphere Application Server you run. When running the single server edition, the TPV runs in the same JVM as your application. In Network Deployment, the TPV runs in the JVM of the deployment manager. Certain functions (like the advisor), however, require resources in the node agents or in the application servers.

WebSphere performance advisors

Gathering information made available through the PMI, the WebSphere performance advisors have the ability to make suggestions about the environment. The advisors are able to determine the current configuration for an application server, and trending the PMI data over time, make informed decisions about potential environmental changes that can enhance the performance of the system. Advice is hard coded into the system and is based on IBM best practices for tuning and performance. The advisors do not implement any changes to the environment. Instead, they identify the problem and allow the system administrator to make the decision whether or not to implement. You should perform tests after any change is implemented. There are two types of advisors:

The Performance Advisor in Tivoli Performance Viewer provides more extensive advice than the Performance and Diagnostic Advisor. Running the Performance Advisor in Tivoli Performance Viewer can require plenty of resources and impact performance. Use it with care in production environments.

WebSphere request metrics

PMI provides information about average system resource usage statistics but does not provide any correlation between the data. Request metrics, in contrast, provide data about each individual transaction and correlate this data.

Request metrics gather information about single transactions within an application. The metric tracks each step of a transaction and determines the process time for each of the major application components. Several components support this transaction metric:

The amount of time that a request spends in each component is measured and aggregated to define the complete execution time for that transaction. Both the individual component times and the overall transaction time can be useful metrics when trying to gauge user experience on a site. The data allows for a hierarchical by response time view for each individual transaction. When debugging resource constraints, these metrics provide critical data at each component. The request metric provides filtering mechanisms to monitor synthetic transactions or to track the performance of a specific transaction. By using test transactions, you can measure performance of the site end-to-end.

From a performance perspective, using transaction request metrics can aid in determining if an application is meeting service level agreements (SLAs) for the client. The metrics can be used to alert the user when an SLA target is not met.

Request metrics help administrators answer the following questions:

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