x/terracotta
Code Issues Proposed changes

Updated loess_abstract to take last n values, fixed tests

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This commit is contained in:
Anton Beloglazov 2012-10-29 16:53:25 +11:00
parent 902a3d795d
commit df55d8b401
2 changed files with 17 additions and 18 deletions
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31
neat/locals/overload/statistics.py
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@ -45,7 +45,7 @@ def loess_factory(time_step, migration_time, params):
migration_time_normalized = float(migration_time) / time_step
return lambda utilization, state=None: \
(loess(params['param'],
params['limit'],
params['length'],
migration_time_normalized,
utilization),
{})
@ -70,7 +70,7 @@ def loess_robust_factory(time_step, migration_time, params):
migration_time_normalized = float(migration_time) / time_step
return lambda utilization, state=None: \
(loess_robust(params['param'],
params['limit'],
params['length'],
migration_time_normalized,
utilization),
{})
@ -123,14 +123,14 @@ def iqr_threshold_factory(time_step, migration_time, params):
@contract
def loess(param, limit, migration_time, utilization):
def loess(param, length, migration_time, utilization):
""" The Loess based overload detection algorithm.
:param param: The safety parameter.
:type param: float
:param limit: The minimum allowed length of the utilization history.
:type limit: int
:param length: The required length of the utilization history.
:type length: int
:param migration_time: The VM migration time in time steps.
:type migration_time: float
@ -143,20 +143,20 @@ def loess(param, limit, migration_time, utilization):
"""
return loess_abstract(loess_parameter_estimates,
param,
limit,
length,
migration_time,
utilization)
@contract
def loess_robust(param, limit, migration_time, utilization):
def loess_robust(param, length, migration_time, utilization):
""" The robust Loess based overload detection algorithm.
:param param: The safety parameter.
:type param: float
:param limit: The minimum allowed length of the utilization history.
:type limit: int
:param length: The required length of the utilization history.
:type length: int
:param migration_time: The VM migration time in time steps.
:type migration_time: float
@ -169,13 +169,13 @@ def loess_robust(param, limit, migration_time, utilization):
"""
return loess_abstract(loess_robust_parameter_estimates,
param,
limit,
length,
migration_time,
utilization)
@contract
def loess_abstract(estimator, param, limit, migration_time, utilization):
def loess_abstract(estimator, param, length, migration_time, utilization):
""" The abstract Loess algorithm.
:param estimator: A parameter estimation function.
@ -184,8 +184,8 @@ def loess_abstract(estimator, param, limit, migration_time, utilization):
:param param: The safety parameter.
:type param: float
:param limit: The minimum allowed length of the utilization history.
:type limit: int
:param length: The required length of the utilization history.
:type length: int
:param migration_time: The VM migration time in time steps.
:type migration_time: float
@ -196,10 +196,9 @@ def loess_abstract(estimator, param, limit, migration_time, utilization):
:return: A decision of whether the host is overloaded.
:rtype: bool
"""
length = len(utilization)
if length < limit:
if len(utilization) < length:
return False
estimates = estimator(utilization)
estimates = estimator(utilization[-length:])
prediction = (estimates[0] + estimates[1] * (length + migration_time))
return param * prediction >= 1.

4
tests/locals/overload/test_statistics.py
View File

@ -25,7 +25,7 @@ class Statistics(TestCase):
def test_loess_factory(self):
alg = stats.loess_factory(
300, 20., {'param': 1.2, 'limit': 3})
300, 20., {'param': 1.2, 'length': 3})
self.assertEqual(alg([]), (False, {}))
data = [1.05, 1.09, 1.07, 1.12, 1.02, 1.18,
@ -39,7 +39,7 @@ class Statistics(TestCase):
def test_loess_robust_factory(self):
alg = stats.loess_robust_factory(
300, 20., {'param': 1.2, 'limit': 3})
300, 20., {'param': 1.2, 'length': 3})
self.assertEqual(alg([]), (False, {}))
data = [1.05, 1.09, 1.07, 1.12, 1.02, 1.18,