def register_up(self):
        """Called by WorkerThread objects to register themselves.

        Acquire the condition variable for the WorkerThread objects.
        Increment the running-thread count.  If we are the last thread to
        start, set status to 'up'.  This allows startall() to complete
        if it was called with wait=True.
        """
        with self.regcond:
            self.runningcount += 1
            tid = thread.get_ident()
            self.tids.append(tid)
            self.logger.debug("register_up: (%d) count is %d" %
                              (tid, self.runningcount))
            if self.runningcount == self.numthreads:
                self.status = 'up'
            self.regcond.notify()
Called by WorkerThread objects to register themselves.

        Acquire the condition variable for the WorkerThread objects.
        Increment the running-thread count.  If we are the last thread to
        start, set status to 'up'.  This allows startall() to complete
        if it was called with wait=True.