This is a Critical Section Controller; it will execute the set of statements (samplers/controllers, etc) under named lock.
In a programming world - this is equivalent of :
try { named_lock.lock(); statements .... } finally { named_lock.unlock(); }
In JMeter you may have :
Thread-Group (set to loop a number of times or indefinitely, ... Samplers ... (e.g. Counter ) ... Other Controllers .... ... CriticalSectionController ( lock name like "foobar" ) ... statements to perform when lock acquired ... ... Other Controllers /Samplers }
@since 2.12