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Spirent iTest: What is the ideal Max Heap Size that can be allocated to iTest JVM?

  • Environment: Windows 7 64bit, 8GB RAM
Based on internal tests, we have the following findings with regards to the Java Heap Space (32 bit JVM) of iTest:
  • Known behavior and limitations:
    • Maximum Usable Heap Space (automatically extended/released by iTest JVM): Approximately 1976MB
      • The maximum allocable heap space and usable heap space may vary in different devices. This is a close approximation of the value.
    • Maximum Heap Space that can be allocated: 2044MB (Modify in iTest.ini -vmargs-Xmx value)
      • FYI: If you use other applications such as Word, heap space may decrease.
  • Best practices and recommendations for efficient usage of iTest Java Heap Space:
    • Reboot the PC (where iTest is installed) before starting large, long-running and/or complex test suites.
      • This is especially effective when tests deal with large content: Reading, Downloads, Streaming and/or Responses greater than 150MB in size.
    • Run iTest as the first application after a PC reboot. It will allow maximum contiguous memory allocation to the application.
    • When running steps that deal with large content (greater than 150MB), give around 15 seconds or more of wait time (sleep) after completion in order to release heap memory.
    • With steps that deal with large content, it is more effective to run them sequentially as opposed to running them in parallel (or multi-threading).
When dealing with extremely large content (greater than 150MB), kindly be advised that the Java heap space may run out over time. The recommendations given above will enable longer running time and more efficient memory usage during testing. However, they cannot completely eliminate the possibility of running out of heap space memory.

Product : iTest Enterprise