15ccf5eb_TestNG_Command_Line_Parameters_Documentation
[Option] -dataproviderthreadcount [Argument] The default number of threads to use for data providers when running tests in parallel. [Documentation] 
This sets the default maximum number of threads to use for data providers when running tests in parallel. It will only take effect if the parallel mode has been selected (for example, with the -parallel option). This can be overridden in the suite definition.
TestNG
Documentation