root / trunk / src / haizea / policies / preemption.py @ 641
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# -------------------------------------------------------------------------- #
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# Copyright 2006-2009, University of Chicago #
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# Copyright 2008-2009, Distributed Systems Architecture Group, Universidad #
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# Complutense de Madrid (dsa-research.org) #
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# #
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# Licensed under the Apache License, Version 2.0 (the "License"); you may #
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# not use this file except in compliance with the License. You may obtain #
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# a copy of the License at #
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# #
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# http://www.apache.org/licenses/LICENSE-2.0 #
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# #
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# Unless required by applicable law or agreed to in writing, software #
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# distributed under the License is distributed on an "AS IS" BASIS, #
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. #
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# See the License for the specific language governing permissions and #
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# limitations under the License. #
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# -------------------------------------------------------------------------- #
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"""This module provides pluggable lease preemption policies. See the documentation
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for haizea.core.schedule.policy.PreemptabilityPolicy for more details on
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lease preemption policies.
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"""
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from haizea.core.leases import Lease |
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from haizea.core.scheduler.policy import PreemptabilityPolicy |
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class NoPreemptionPolicy(PreemptabilityPolicy): |
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"""Simple preemption policy: preemption is never allowed.
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"""
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def __init__(self, slottable): |
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"""Constructor
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Argument
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slottable -- A fully constructed SlotTable
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"""
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PreemptabilityPolicy.__init__(self, slottable)
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def get_lease_preemptability_score(self, preemptor, preemptee, time): |
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"""Computes the lease preemptability score
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See class documentation for details on what policy is implemented here.
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See documentation of PreemptabilityPolicy.get_lease_preemptability_score
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for more details on this function.
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Arguments:
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preemptor -- Preemptor lease
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preemptee -- Preemptee lease
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time -- Time at which preemption would take place
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"""
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return -1 |
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class ARPreemptsEverythingPolicy(PreemptabilityPolicy): |
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"""A simple preemption policy where AR leases can always preempt
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every other type of lease. Given two possible leases to preempt,
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the "youngest" one is preferred (i.e., the one that was most recently
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submitted).
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"""
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def __init__(self, slottable): |
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"""Constructor
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Argument
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slottable -- A fully constructed SlotTable
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"""
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PreemptabilityPolicy.__init__(self, slottable)
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def get_lease_preemptability_score(self, preemptor, preemptee, time): |
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"""Computes the lease preemptability score
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See class documentation for details on what policy is implemented here.
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See documentation of PreemptabilityPolicy.get_lease_preemptability_score
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for more details on this function.
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Arguments:
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preemptor -- Preemptor lease
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preemptee -- Preemptee lease
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time -- Time at which preemption would take place
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"""
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if preemptor.get_type() == Lease.ADVANCE_RESERVATION and preemptee.get_type() == Lease.BEST_EFFORT: |
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return self._get_aging_factor(preemptee, time) |
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else:
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return -1 |