When you perform multisite testing, you can improve performance by simultaneously testing multiple sites using multiple execution threads. When you use the TestStand Batch process model to test multiple sites, TestStand executes the test program in separate threads automatically. LabVIEW, however, by default does not allow multiple instances of a VI to execute simultaneously. Each call to a VI must wait until other calls to the VI finish executing. To maximize parallel execution of test code, use reentrant VIs and subVIs.

Complete the following steps to configure a VI to set the execution properties for a VI.

1. From the front panel or block diagram of a VI, select File » VI Properties and select Execution from the Category drop-down menu to launch the Execution page.
2. Set the Reentrancy option to Shared clone reentrant execution. Do not use the Preallocated clone reentrant execution option because that option might cause LabVIEW to allocate significantly more resources to execute VIs and can result in high memory usage and long delays when unloading the test program.

Refer to the LabVIEW Help for more information about reentrant VIs. In LabVIEW, select Help » LabVIEW Help to launch the LabVIEW Help.