107 lines
3.5 KiB
Python
107 lines
3.5 KiB
Python
# Copyright 2012 Anton Beloglazov
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
|
|
""" OTF threshold based algorithms.
|
|
"""
|
|
|
|
from contracts import contract
|
|
from neat.contracts_primitive import *
|
|
from neat.contracts_extra import *
|
|
|
|
import logging
|
|
log = logging.getLogger(__name__)
|
|
|
|
|
|
@contract
|
|
def otf_factory(time_step, migration_time, params):
|
|
""" Creates the OTF algorithm with limiting and migration time.
|
|
|
|
:param time_step: The length of the simulation time step in seconds.
|
|
:type time_step: int,>=0
|
|
|
|
:param migration_time: The VM migration time in time seconds.
|
|
:type migration_time: float,>=0
|
|
|
|
:param params: A dictionary containing the algorithm's parameters.
|
|
:type params: dict(str: *)
|
|
|
|
:return: A function implementing the OTF algorithm.
|
|
:rtype: function
|
|
"""
|
|
migration_time_normalized = float(migration_time) / time_step
|
|
def otf_wrapper(utilization, state=None):
|
|
if state is None or state == {}:
|
|
state = {'overload': 0,
|
|
'total': 0}
|
|
return otf(params['otf'],
|
|
params['threshold'],
|
|
params['limit'],
|
|
migration_time_normalized,
|
|
utilization,
|
|
state)
|
|
|
|
return otf_wrapper
|
|
|
|
|
|
@contract
|
|
def otf(otf, threshold, limit, migration_time, utilization, state):
|
|
""" The OTF threshold algorithm with limiting and migration time.
|
|
|
|
:param otf: The threshold on the OTF value.
|
|
:type otf: float,>=0
|
|
|
|
:param threshold: The utilization overload threshold.
|
|
:type threshold: float,>=0
|
|
|
|
:param limit: The minimum number of values in the utilization history.
|
|
:type limit: int,>=0
|
|
|
|
:param migration_time: The VM migration time in time steps.
|
|
:type migration_time: float,>=0
|
|
|
|
:param utilization: The history of the host's CPU utilization.
|
|
:type utilization: list(float)
|
|
|
|
:param state: The state dictionary.
|
|
:type state: dict(str: *)
|
|
|
|
:return: The decision of the algorithm and updated state.
|
|
:rtype: tuple(bool, dict(*: *))
|
|
"""
|
|
state['total'] += 1
|
|
overload = (utilization[-1] >= threshold)
|
|
if overload:
|
|
state['overload'] += 1
|
|
|
|
if log.isEnabledFor(logging.DEBUG):
|
|
log.debug('OTF overload:' + str(overload))
|
|
log.debug('OTF overload steps:' + str(state['overload']))
|
|
log.debug('OTF total steps:' + str(state['total']))
|
|
log.debug('OTF:' + str(float(state['overload']) / state['total']))
|
|
log.debug('OTF migration time:' + str(migration_time))
|
|
log.debug('OTF + migration time:' +
|
|
str((migration_time + state['overload']) / \
|
|
(migration_time + state['total'])))
|
|
log.debug('OTF decision:' +
|
|
str(overload and (migration_time + state['overload']) / \
|
|
(migration_time + state['total']) >= otf))
|
|
|
|
if not overload or len(utilization) < limit:
|
|
decision = False
|
|
else:
|
|
decision = (migration_time + state['overload']) / \
|
|
(migration_time + state['total']) >= otf
|
|
|
|
return (decision, state)
|