IBM Support

Mustgather: Setup for hang or performance problems on Linux

Technote (troubleshooting)


If your Java application experiences perceived hang or performance problems on a Linux operating system, there are a number of diagnostic data files that are useful for diagnosing the problem. This mustgather document describes about the required settings to be in place in order to generate those diagnostic data files.

Resolving the problem

In order to collect the diagnostic data files required for diagnosing the hang or performance problems, check that the following specific settings are configured before running your application:
1. Enable javacore generation
2. Enable coredump generation
3. Enable verbose GC collection
Please use -verbose:gc option for the same
4. Enable process sizes monitoring
5. Enable paging usage monitoring
6. Enable processor usage monitoring
7. Install tprof utility and configure with the following option:

Please note that both the javacore and core dump generation can be enabled
using the below single Xdump option:

Another easier way to quickly identify the performance bottlenecks and improve the efficiency of your Java application is to use the IBM® Monitoring and Diagnostic Tools for Java – Health Center tool. It also helps you to assess the status of the running Java application.

Using the IBM Monitoring and Diagnostic Tools for Java - Health Center

Information about installing and configuring the Health Center tool is provided at:

The IBM Health Center is a low overhead monitoring tool which runs alongside an IBM Java application and provides a comprehensive view of the "health" of various subsystems. Please refer the IBM Health Center Information center document for more information.

For more details about enabling these settings, please see the related information links.

Related information

Verbose GC
Paging usage
Process Size
Core dump
CPU monitoring
TProf Installation
Health Center

Document information

More support for: Runtimes for Java Technology
Hangs/Performance Degradation

Software version: 5.0, 6.0, 6.1, 7.0, 7.1, 8.0

Operating system(s): Linux

Software edition: J2SE

Reference #: 1222462

Modified date: 07 March 2017