def _check_repeat(self, prev_run_time):
"""Check if the :attr:`addon` wants to repeat.
And set it up if so.
"""
self._repeat = (None, None)
rcu_copy = self._start_schedule_rcu_copy
if rcu_copy is None:
rcu_copy = self._rcu.copy()
rcu_data = rcu_copy.data
if rcu_data.last_idx is None:
return
chain = rcu_data.ready_chains[rcu_data.last_idx]
current_time = yield CPURequest.current_time()
done = chain.bottom.is_finished() or chain.bottom.ready_time > current_time
repeat, time_slice = self.addon.repeat(rcu_data, prev_run_time, done)
if not repeat:
return
assert not done
assert time_slice is None or time_slice > 0
self._repeat = (rcu_copy, time_slice)
def _start_schedule(self, _prev_run_time):
"""Prepare making a scheduling decision.
Moves ready threads to the ready queue
and finished ones to the finished queue.
Returns a tuple (
* RCUCopy of :attr:`_rcu`
* list where previously scheduled chain ended up
* (`rcu_copy_{ready,waiting,finished}_chains`)
* index of previously scheduled chain
* as passed to :meth:`_schedule`
* *not* necessarily the index into the list where the chain ended up
).
Yields an idle or execute :class:`~schedsi.cpurequest.Request`.
Consumes the current time.
"""
current_time = yield CPURequest.current_time()
while True:
rcu_copy = self._rcu.copy()
rcu_data = rcu_copy.data
# check if the last scheduled thread is done now
# move to a different queue is necessary
dest = None
last_idx = None
if rcu_data.last_idx is not None:
last_idx = rcu_data.last_idx
last_context = rcu_data.ready_chains[last_idx]
if last_context.bottom.is_finished():
dest = rcu_data.finished_chains
elif last_context.bottom.ready_time > current_time:
dest = rcu_data.waiting_chains
else:
assert last_context.bottom.ready_time != -1
if dest is None:
dest = rcu_data.ready_chains
else:
dest.append(rcu_data.ready_chains.pop(last_idx))
# if not self._rcu.update(rcu_copy):
# # current_time = yield CPURequest.execute(1)
# continue
self._update_ready_chains(current_time, rcu_data)
rcu_data.last_idx = None
return rcu_copy, dest, last_idx
def _start_schedule(self, prev_run_time):
"""See :meth:`Scheduler._start_schedule`.
This skips :meth:`Scheduler._start_schedule`
if :attr:`_start_schedule_rcu_copy` is set.
Resets :attr:`_start_schedule_rcu_copy` to `None`.
"""
if self._start_schedule_rcu_copy is None:
return (yield from super()._start_schedule(prev_run_time))
rcu_copy = self._start_schedule_rcu_copy
self._start_schedule_rcu_copy = None
idx = rcu_copy.data.last_idx
self._update_ready_chains((yield CPURequest.current_time()), rcu_copy.data)
rcu_copy.data.last_idx = None
return rcu_copy, rcu_copy.data.ready_chains, idx
def _schedule(self, idx, time_slice, next_ready_time, rcu_copy):
"""Update :attr:`_rcu` and schedule the chain at `idx`.
If `idx` is `None`, yield an idle request.
`next_ready_time` should be forwarded from :meth:`schedule`.
Yields a :class:`~schedsi.cpurequest.Request`.
"""
rcu_data = rcu_copy.data
rcu_data.last_idx = idx
# FIXME: we need to take it out of the ready_chains for multi-vcpu
# else we might try to run the same chain in parallel
if not self._rcu.update(rcu_copy):
return
if idx is None:
next_chain = self.get_next_waiting(rcu_copy.data)
if next_chain:
next_ready_time[0] = next_chain.bottom.ready_time
current_time = yield CPURequest.current_time()
delta = next_chain.bottom.ready_time - current_time
assert delta > 0
yield CPURequest.timer(delta)
else:
next_ready_time[0] = None
yield CPURequest.idle()
return
next_ready_time[0] = 0
yield CPURequest.timer(time_slice)
chain = yield CPURequest.resume_chain(rcu_data.ready_chains[idx])
def appliance(data):
"""Update executed chain."""
data.ready_chains[idx] = chain
self._rcu.apply(appliance)
def _start_schedule(self, prev_run_time): # pylint: disable=method-hidden
"""See :meth:`Scheduler._start_schedule`.
Lower priority of last thread if it outran its time-slice.
Boost priorities if it's time.
"""
rcu_copy, last_queue, last_idx = yield from super()._start_schedule(prev_run_time)
rcu_data = rcu_copy.data
prev_still_ready = last_queue is rcu_data.ready_chains
prev_has_run = prev_run_time is not None and prev_run_time > 0
prev_level = next(i for i, v in enumerate(rcu_data.ready_queues)
if v is rcu_data.ready_chains)
if prev_has_run:
# important: == vs is; empty arrays will compare equal with ==
current_time = (yield CPURequest.current_time())
if self._priority_boost(rcu_data, prev_level, current_time) \
and prev_still_ready:
last_queue = rcu_data.ready_queues[0]
if prev_still_ready:
# rotate queue for round robin
last_queue.append(last_queue.pop(last_idx))
last_idx = len(last_queue) - 1
# switch to highest priority queue
rcu_data.ready_chains = next((x for x in rcu_data.ready_queues if x),
rcu_data.ready_queues[0])
if prev_has_run and not last_queue[-1].bottom.is_finished():
# and (rcu_data.last_prio_boost is None or rcu_data.last_prio_boost != current_time) ?
last_queue = self._priority_reduction(rcu_data, last_queue,
prev_still_ready, prev_level, prev_run_time)
if rcu_data.waiting_chains:
assert last_queue is rcu_data.waiting_chains
last_queue = rcu_data.waiting_queues[prev_level]
last_queue.append(rcu_data.waiting_chains.pop())
assert not rcu_data.waiting_chains
return rcu_copy, last_queue, last_idx
def _sched_loop(self, rcu_copy):
"""Schedule the next :class:`~schedsi.threads.Thread`.
See :meth:`Scheduler._sched_loop() <schedsi.scheduler.Scheduler._sched_loop>`.
"""
rcu_data = rcu_copy.data
if not rcu_data.ready_chains:
return None, None
# important: == vs is; empty arrays will compare equal with ==
level = next(i for i, v in enumerate(rcu_data.ready_queues)
if v is rcu_data.ready_chains)
time_slice = self.level_time_slices[level]
rcu_data.last_finish_time = None
if time_slice is not None:
rcu_data.last_finish_time = (yield CPURequest.current_time()) + time_slice
return 0, time_slice
def _sched_loop(self, rcu_copy): # pylint: disable=no-self-use
"""See :meth:`FCFS._sched_loop`."""
idx, time_slice = yield from super()._sched_loop(rcu_copy)
if idx is not None:
assert idx == 0
threads = (c.bottom for c in rcu_copy.data.waiting_chains)
next_thread = next(threads, None)
for thread in threads:
if thread.ready_time < next_thread.ready_time or (
thread.ready_time == next_thread.ready_time
and thread.remaining < next_thread.remaining):
next_thread = thread
current_remaining = rcu_copy.data.ready_chains[0].bottom.remaining
if next_thread is not None and next_thread.remaining is not None and (
current_remaining is None or next_thread.remaining < current_remaining):
# calculate time to preemption
current_time = yield CPURequest.current_time()
time_slice = next_thread.ready_time - current_time
assert time_slice > 0
return idx, time_slice
def _schedule(self, idx, time_slice, next_ready_time, rcu_copy):
"""See :meth:`Scheduler._schedule`.
This will also call the :attr:`addon`'s :meth:`~Addon.schedule`.
"""
proceed, time_slice = self.addon.schedule(idx, time_slice, rcu_copy.data)
if not proceed:
rcu_copy.data.last_idx = idx
self._start_schedule_rcu_copy = rcu_copy
if self._repeat[0] is not None:
# block repeating
self.addon.repeat(rcu_copy.data, 0, True)
return
schedule = super()._schedule(idx, time_slice, next_ready_time, rcu_copy)
answer = None
while True:
try:
request = schedule.send(answer)
except StopIteration:
break
if request.rtype == CPURequestType.timer:
delta = None
if next_ready_time[0] != 0:
if next_ready_time[0] is not None:
current_time = yield CPURequest.current_time()
delta = next_ready_time[0] - current_time
# if this assumption does not hold we need to decide
# whether we really want to override this
assert delta == request.arg
if time_slice is None or delta is None:
request.arg = time_slice
answer = yield request