TestNG parallel Execution with DataProvider

Try to set the thread pool in following way:

@BeforeClass
public void setupClassName(ITestContext context) {
    context.getCurrentXmlTest().getSuite().setDataProviderThreadCount(5);
    context.getCurrentXmlTest().getSuite().setPreserveOrder(false);
}

You need to use dataproviderthreadcount. The threadpoolsize and invocationcount values are not required. See details here.