def _inner():
            if initial_delay:
                greenthread.sleep(initial_delay)

            try:
                while self._running:
                    start = _ts()
                    self.f(*self.args, **self.kw)
                    end = _ts()
                    if not self._running:
                        break
                    delay = end - start - interval
                    if delay > 0:
                        LOG.warn(_LW('task %(func_name)s run outlasted '
                                     'interval by %(delay).2f sec'),
                                 {'func_name': repr(self.f), 'delay': delay})
                    greenthread.sleep(-delay if delay < 0 else 0)
            except LoopingCallDone as e:
                self.stop()
                done.send(e.retvalue)
            except Exception:
                LOG.exception(_LE('in fixed duration looping call'))
                done.send_exception(*sys.exc_info())
                return
            else:
                done.send(True)
        def _inner():
            if initial_delay:
                greenthread.sleep(initial_delay)

            try:
                while self._running:
                    start = timeutils.utcnow()
                    self.f(*self.args, **self.kw)
                    end = timeutils.utcnow()
                    if not self._running:
                        break
                    delay = interval - timeutils.delta_seconds(start, end)
                    if delay <= 0:
                        LOG.warn(_LW('task run outlasted interval by %s sec') %
                                 -delay)
                    greenthread.sleep(delay if delay > 0 else 0)
            except LoopingCallDone as e:
                self.stop()
                done.send(e.retvalue)
            except Exception:
                LOG.exception(_LE('in fixed duration looping call'))
                done.send_exception(*sys.exc_info())
                return
            else:
                done.send(True)
        def _inner():
            if initial_delay:
                greenthread.sleep(initial_delay)

            try:
                while self._running:
                    idle = self.f(*self.args, **self.kw)
                    if not self._running:
                        break

                    if periodic_interval_max is not None:
                        idle = min(idle, periodic_interval_max)
                    LOG.debug('Dynamic looping call %(func_name)s sleeping '
                              'for %(idle).02f seconds',
                              {'func_name': repr(self.f), 'idle': idle})
                    greenthread.sleep(idle)
            except LoopingCallDone as e:
                self.stop()
                done.send(e.retvalue)
            except Exception:
                LOG.exception(_LE('in dynamic looping call'))
                done.send_exception(*sys.exc_info())
                return
            else:
                done.send(True)
        def _inner():
            if initial_delay:
                greenthread.sleep(initial_delay)

            try:
                while self._running:
                    idle = self.f(*self.args, **self.kw)
                    if not self._running:
                        break

                    if periodic_interval_max is not None:
                        idle = min(idle, periodic_interval_max)
                    LOG.debug('Dynamic looping call sleeping for %.02f '
                              'seconds', idle)
                    greenthread.sleep(idle)
            except LoopingCallDone as e:
                self.stop()
                done.send(e.retvalue)
            except Exception:
                LOG.exception(_LE('in dynamic looping call'))
                done.send_exception(*sys.exc_info())
                return
            else:
                done.send(True)