It depends what you need to achieve with this call.
Apple states that it should be used for debugging anyway.
Perhaps the queue does not matter (as you just need a background queue) so get a global queue with specific priority (dispatch_get_global_queue(dispatch_queue_priority_t priority,)
unsigned long flags);
OR,
If you do need to execute some pieces of code in the same queue , create a queue, retain it and dispatch all your tasks there.