class Stfq(SchedulingAlgorithm):
"""Start-Time Fair Queuing (STFQ)"""
def __init__(self, name=None):
super().__init__(name)
self._pifo = Pifo()
self._last_finish = {}
self._virt_time = 0
def get_rank(self, item):
"""Rank the items by their start time, which we calculate from the
finish time of the last packet.
"""
flow_id = item.flow
if flow_id in self._last_finish:
rank = max(self._virt_time, self._last_finish[flow_id])
else:
rank = self._virt_time
self._last_finish[flow_id] = rank + item.length
return rank
def enqueue(self, ref, item):
rank = self.get_rank(item)
self._pifo.enqueue(ref, rank)
def dequeue(self):
return self._pifo.dequeue()
def dump(self):
self._pifo.dump()
class Wfq(SchedulingAlgorithm):
"""Weighted Fair Queueing (WFQ)"""
def __init__(self, name=None):
super().__init__(name)
self._pifo = Pifo()
self._last_finish = {}
self._virt_time = 0
def get_rank(self, item):
"""Rank the items by their start time, which we calculate from the
finish time of the last packet. However, we divide the packet's length
with weights to prioritize them. We determine the weights by splitting
the flow-ids into odd and even numbers.
"""
flow = item.flow
weight = 50 if flow % 2 == 1 else 100
if flow in self._last_finish:
rank = max(self._virt_time, self._last_finish[flow])
else:
rank = self._virt_time
self._last_finish[flow] = rank + item.length / weight
return rank
def enqueue(self, ref, item):
rank = self.get_rank(item)
self._pifo.enqueue(ref, rank)
def dequeue(self):
return self._pifo.dequeue()
def dump(self):
self._pifo.dump()
def __init__(self, name=None):
super().__init__(name)
self._pifo = Pifo()
self._flow_tracker = FlowTracker()
self._remains = {}
# We cheat by accessing the global packet list directly
for pkt in pkts:
if pkt.flow in self._remains.keys():
self._remains[pkt.flow] += pkt.length
else:
self._remains[pkt.flow] = pkt.length
class Fifo(SchedulingAlgorithm):
"""First in, first out (FIFO)"""
def __init__(self, name=None):
super().__init__(name)
self._pifo = Pifo()
def get_rank(self, _):
"""Rank the items in FIFO order."""
return self._pifo.qlen
def enqueue(self, ref, item):
rank = self.get_rank(item)
self._pifo.enqueue(ref, rank)
def dequeue(self):
return self._pifo.dequeue()
def dump(self):
self._pifo.dump()
class Srpt(SchedulingAlgorithm):
"""Shortest Remaining Processing Time"""
def __init__(self, name=None):
super().__init__(name)
self._pifo = Pifo()
self._flow_tracker = FlowTracker()
self._remains = {}
# We cheat by accessing the global packet list directly
for pkt in pkts:
if pkt.flow in self._remains.keys():
self._remains[pkt.flow] += pkt.length
else:
self._remains[pkt.flow] = pkt.length
def get_rank(self, item):
"""Rank the items by their remaining total flow length."""
rank = self._remains[item.flow]
self._remains[item.flow] -= item.length
return rank
def enqueue(self, ref, item):
flow = self._flow_tracker.enqueue(item)
rank = self.get_rank(item)
self._pifo.enqueue(flow, rank)
def dequeue(self):
flow = self._pifo.dequeue()
item = None
if flow is not None:
item = flow.dequeue()
return item
def dump(self):
self._pifo.dump()
def __init__(self, name=None):
super().__init__(name)
self._pifo = Pifo()
self._last_finish = {}
self._virt_time = 0
def __init__(self, name=None):
super().__init__(name)
self._pifo = Pifo()