Enabling PMI data collection

Enable PMI data collection to diagnose problems and tune application performance.

Before you begin

Performance Monitoring Infrastructure (PMI) must be enabled (by default PMI is enabled) before you collect any performance data. PMI must be enabled before the server starts. If PMI is enabled after the server is started, the server needs to be restarted to start the PMI.

About this task

When PMI service is enabled, the monitoring of individual components can be enabled or disabled dynamically. PMI provides four predefined statistic sets that can be used to enable a set of statistics. The following table provides details about the statistic sets. If the predefined statistic sets do not meet your monitoring requirement, the Custom option can be used to selectively enable or disable individual statistics.

Table 1. Statistic set . Enable PMI by using the administrative console, wsadmin tool, or Java™ Virtual Machine Tool Interface (JVMTI).
Statistic set Description
None All statistics are disabled.
Basic Statistics that are specified in J2EE 1.4, and popular statistics like CPU usage and live HTTP sessions are enabled. This set is enabled out-of-the-box and provides basic performance data about runtime and application components.
[AIX Solaris HP-UX Linux Windows][IBM i]Extended [AIX Solaris HP-UX Linux Windows][IBM i]Basic set plus key statistics from various WebSphere® Application Server components like WLM, and dynamic caching are enabled. This set provides detailed performance data about various runtime and application components.
All All statistics are enabled.
Custom Enable or disable statistics selectively.

Custom setting

WebSphere Application Server Version 6.0 introduces fine-grained control to enable/disable statistics individually. The fine-grained control is available under the custom statistic set.

Sequential Update

To minimize the monitoring overhead, the updates to CountStatistic, AverageStatistic, and TimeStatistic are not synchronized. Since these statistic types track total and average, the extra accuracy is not worth the performance cost. The RangeStatistic and BoundedRangeStatistic are sensitive; therefore, they are always synchronized. If needed, updates to all the statistic types can be synchronized by checking the Use sequential update check box.

[z/OS][AIX Solaris HP-UX Linux Windows]Intelligent Management depends on some Performance Monitoring Infrastructure (PMI) metrics. When Intelligent Management is enabled, the application server cannot disable PMI metrics that Intelligent Management requires. However, you can add extra counters beyond the Intelligent Management PMI defaults.
Table 2. Locked PMI metrics . You cannot disable PMI metrics that Intelligent Management uses without first disabling Intelligent Management.
Locking locations Module Module counters that are locked
Nodeagent, server, or on-demand router xdProcessModule All
Nodeagent, server, or on-demand router jvmRuntimeModule All
Nodeagent, server, or on-demand router systemModule All
Nodeagent, server, or on-demand router threadPoolModule 6, 7, 8
Nodeagent, server, or on-demand router xdHeapModule All
Nodeagent, server, or on-demand router odrStatModule All
Nodeagent xdSystemModule All
Server or on-demand router DeploymentTargets All
Server or on-demand router xdOdrSessionModule All
Server or on-demand router servletSessionsModule 6, 7
Server or on-demand router beanModule 11, 12
Server or on-demand router webAppModule 11, 13

Procedure

Results

For information about PMI module counters and their properties, see PMI data organization.