Rational Performance Tester testing tips

 

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Number of computers

The user interface consumes significant resources, therefore play back a test or schedule on a computer (agent) that is separate from the computer that is running the workbench (UI).


Number of virtual users at remote locations.

Do not overload the remote computer (agent) for user groups at remote locations. If you exceed the number of virtual users that the remote computer can run, the performance measurements of the server will be skewed because they will be affected by the performance of the computer. The test results will reflect the load of the computer more than the load of the server.

For best results on a computer with a 1 GHz processor and 1 GB of RAM, do not exceed 1000 concurrent virtual users.


TCP/IP ports

Vefiy there is a sufficient number of TCP/IP ports. On Windows, the typical limit is 5000.

To observe port use...

If the largest number you see is 5000, increase the number...

  1. Edit the registry (regidt)

  2. Go to...

      HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/Tcpip/Parameters

  3. Create a new dWord named MaxUserPort, and set its value up to 65000

  4. Restart the computer.


Open file limit for Linux

Linux computers need per process open file limit higher than 1024. Before starting Agent Controller, as root, enter ulimit -n 30000 (or another appropriate value).


Looping within tests

For stress testing with loops, connection behavior differs depending upon whether the loop is set at the schedule level or at the test level.

Setting a loop at the test level, rather than the schedule level, gives you a performance advantage, because the connections are reused during the looping process.


Logging levels

After the test is stable, for maximum performance, reduce the test log level and problem determination log level and sample a small number of users. Increase the statistics sample interval to 30 or 60 seconds for long-running tests.


Workbench heap size

The JVM heap size on the workbench is based on the physical memory available. Do not run the workbench on a computer with less than 768 MB of physical memory. The maximum workbench heap size depends on JVM.

While not strictly necessary for playback performance, you can increase the workbench heap size.

To increase the heap size, set the -Xmx parameter in the eclipse.ini file, which is located in RPTv8 installation directory.

If the workbench is sluggish or fails to start after you increase the heap size, reset the heap size to the default editing eclipse.ini and removing...


Location (agent) heap size

To access maximum heap, after one successful test of any size, search for a location (agent) attribute called RPT_DEFAULT_MEMORY_SIZE. If you cannot find this attribute, you can specify a maximum heap by creating a new attribute:

For example, max heap 1.5GB.