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Diffstat (limited to 'resources/libraries/python/MLRsearch')
7 files changed, 806 insertions, 0 deletions
diff --git a/resources/libraries/python/MLRsearch/AbstractMeasurer.py b/resources/libraries/python/MLRsearch/AbstractMeasurer.py new file mode 100644 index 0000000000..b972c4eb18 --- /dev/null +++ b/resources/libraries/python/MLRsearch/AbstractMeasurer.py @@ -0,0 +1,35 @@ +# Copyright (c) 2018 Cisco and/or its affiliates. +# 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. + +"""Module defining AbstractMeasurer class.""" + +from abc import ABCMeta, abstractmethod + + +class AbstractMeasurer(object): + """Abstract class defining common API for measurement providers.""" + + __metaclass__ = ABCMeta + + @abstractmethod + def measure(self, duration, transmit_rate): + """Perform trial measurement and return the result. + + :param duration: Trial duration [s]. + :param transmit_rate: Target transmit rate [pps]. + :type duration: float + :type transmit_rate: float + :returns: Structure containing the result of the measurement. + :rtype: ReceiveRateMeasurement + """ + pass diff --git a/resources/libraries/python/MLRsearch/AbstractSearchAlgorithm.py b/resources/libraries/python/MLRsearch/AbstractSearchAlgorithm.py new file mode 100644 index 0000000000..538322a42c --- /dev/null +++ b/resources/libraries/python/MLRsearch/AbstractSearchAlgorithm.py @@ -0,0 +1,51 @@ +# Copyright (c) 2018 Cisco and/or its affiliates. +# 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. + +"""Module defining AbstractSearchAlgorithm class.""" + +from abc import ABCMeta, abstractmethod + + +class AbstractSearchAlgorithm(object): + """Abstract class defining common API for search algorithms.""" + + __metaclass__ = ABCMeta + + def __init__(self, measurer): + """Store the rate provider. + + :param measurer: Object able to perform trial or composite measurements. + :type measurer: AbstractMeasurer + """ + # TODO: Type check for AbstractMeasurer? + self.measurer = measurer + + @abstractmethod + def narrow_down_ndr_and_pdr( + self, fail_rate, line_rate, packet_loss_ratio): + """Perform measurements to narrow down intervals, return them. + + This will be renamed when custom loss ratio lists are supported. + + :param fail_rate: Minimal target transmit rate [pps]. + :param line_rate: Maximal target transmit rate [pps]. + :param packet_loss_ratio: Fraction of packets lost, for PDR [1]. + :type fail_rate: float + :type line_rate: float + :type packet_loss_ratio: float + :returns: Structure containing narrowed down intervals + and their measurements. + :rtype: NdrPdrResult + """ + # TODO: Do we agree on arguments related to precision or trial duration? + pass diff --git a/resources/libraries/python/MLRsearch/MultipleLossRatioSearch.py b/resources/libraries/python/MLRsearch/MultipleLossRatioSearch.py new file mode 100644 index 0000000000..0eb1d7da4c --- /dev/null +++ b/resources/libraries/python/MLRsearch/MultipleLossRatioSearch.py @@ -0,0 +1,501 @@ +# Copyright (c) 2018 Cisco and/or its affiliates. +# 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. + +"""Module defining MultipleLossRatioSearch class.""" + +import logging +import math +import time + +from AbstractSearchAlgorithm import AbstractSearchAlgorithm +from NdrPdrResult import NdrPdrResult +from ReceiveRateInterval import ReceiveRateInterval + + +class MultipleLossRatioSearch(AbstractSearchAlgorithm): + """Optimized binary search algorithm for finding NDR and PDR bounds. + + Traditional binary search algorithm needs initial interval + (lower and upper bound), and returns final interval after bisecting + (until some exit condition is met). + The exit condition is usually related to the interval width, + (upper bound value minus lower bound value). + + The optimized algorithm contains several improvements + aimed to reduce overall search time. + + One improvement is searching for two intervals at once. + The intervals are for NDR (No Drop Rate) and PDR (Partial Drop Rate). + + Next improvement is that the initial interval does not need to be valid. + Imagine initial interval (10, 11) where 11 is smaller + than the searched value. + The algorithm will try (11, 13) interval next, and if 13 is still smaller, + (13, 17) and so on, doubling width until the upper bound is valid. + The part when interval expands is called external search, + the part when interval is bisected is called internal search. + + Next improvement is that trial measurements at small trial duration + can be used to find a reasonable interval for full trial duration search. + This results in more trials performed, but smaller overall duration + in general. + + Next improvement is bisecting in logarithmic quantities, + so that exit criteria can be independent of measurement units. + + Next improvement is basing the initial interval on receive rates. + + Final improvement is exiting early if the minimal value + is not a valid lower bound. + + The complete search consist of several phases, + each phase performing several trial measurements. + Initial phase creates initial interval based on receive rates + at maximum rate and at maximum receive rate (MRR). + Final phase and preceding intermediate phases are performing + external and internal search steps, + each resulting interval is the starting point for the next phase. + The resulting interval of final phase is the result of the whole algorithm. + + Each non-initial phase uses its own trial duration and width goal. + Any non-initial phase stops searching (for NDR or PDR independently) + when minimum is not a valid lower bound (at current duration), + or all of the following is true: + Both bounds are valid, bound bounds are measured at the current phase + trial duration, interval width is less than the width goal + for current phase. + + TODO: Review and update this docstring according to rst docs. + TODO: Support configurable number of Packet Loss Ratios. + """ + + class ProgressState(object): + """Structure containing data to be passed around in recursion.""" + + def __init__( + self, result, phases, duration, width_goal, packet_loss_ratio, + minimum_transmit_rate, maximum_transmit_rate): + """Convert and store the argument values. + + :param result: Current measured NDR and PDR intervals. + :param phases: How many intermediate phases to perform + before the current one. + :param duration: Trial duration to use in the current phase [s]. + :param width_goal: The goal relative width for the curreent phase. + :param packet_loss_ratio: PDR fraction for the current search. + :param minimum_transmit_rate: Minimum target transmit rate + for the current search [pps]. + :param maximum_transmit_rate: Maximum target transmit rate + for the current search [pps]. + :type result: NdrPdrResult + :type phases: int + :type duration: float + :type width_goal: float + :type packet_loss_ratio: float + :type minimum_transmit_rate: float + :type maximum_transmit_rate: float + """ + self.result = result + self.phases = int(phases) + self.duration = float(duration) + self.width_goal = float(width_goal) + self.packet_loss_ratio = float(packet_loss_ratio) + self.minimum_transmit_rate = float(minimum_transmit_rate) + self.maximum_transmit_rate = float(maximum_transmit_rate) + + def __init__(self, measurer, final_relative_width=0.005, + final_trial_duration=30.0, initial_trial_duration=1.0, + number_of_intermediate_phases=2, timeout=600.0): + """Store the measurer object and additional arguments. + + :param measurer: Rate provider to use by this search object. + :param final_relative_width: Final lower bound transmit rate + cannot be more distant that this multiple of upper bound [1]. + :param final_trial_duration: Trial duration for the final phase [s]. + :param initial_trial_duration: Trial duration for the initial phase + and also for the first intermediate phase [s]. + :param number_of_intermediate_phases: Number of intermediate phases + to perform before the final phase [1]. + :param timeout: The search will fail itself when not finished + before this overall time [s]. + :type measurer: AbstractMeasurer + :type final_relative_width: float + :type final_trial_duration: float + :type initial_trial_duration: int + :type number_of_intermediate_phases: int + :type timeout: float + """ + super(MultipleLossRatioSearch, self).__init__(measurer) + self.final_trial_duration = float(final_trial_duration) + self.final_relative_width = float(final_relative_width) + self.number_of_intermediate_phases = int(number_of_intermediate_phases) + self.initial_trial_duration = float(initial_trial_duration) + self.timeout = float(timeout) + + + @staticmethod + def double_relative_width(relative_width): + """Return relative width corresponding to double logarithmic width. + + :param relative_width: The base relative width to double. + :type relative_width: float + :returns: The relative width of double logarithmic size. + :rtype: float + """ + return 1.999 * relative_width - relative_width * relative_width + # The number should be 2.0, but we want to avoid rounding errors, + # and ensure half of double is not larger than the original value. + + @staticmethod + def double_step_down(relative_width, current_bound): + """Return rate of double logarithmic width below. + + :param relative_width: The base relative width to double. + :param current_bound: The current target transmit rate to move [pps]. + :type relative_width: float + :type current_bound: float + :returns: Transmit rate smaller by logarithmically double width [pps]. + :rtype: float + """ + return current_bound * ( + 1.0 - MultipleLossRatioSearch.double_relative_width( + relative_width)) + + @staticmethod + def double_step_up(relative_width, current_bound): + """Return rate of double logarithmic width above. + + :param relative_width: The base relative width to double. + :param current_bound: The current target transmit rate to move [pps]. + :type relative_width: float + :type current_bound: float + :returns: Transmit rate larger by logarithmically double width [pps]. + :rtype: float + """ + return current_bound / ( + 1.0 - MultipleLossRatioSearch.double_relative_width( + relative_width)) + + @staticmethod + def half_relative_width(relative_width): + """Return relative width corresponding to half logarithmic width. + + :param relative_width: The base relative width to halve. + :type relative_width: float + :returns: The relative width of half logarithmic size. + :rtype: float + """ + return 1.0 - math.sqrt(1.0 - relative_width) + + @staticmethod + def half_step_up(relative_width, current_bound): + """Return rate of half logarithmic width above. + + :param relative_width: The base relative width to halve. + :param current_bound: The current target transmit rate to move [pps]. + :type relative_width: float + :type current_bound: float + :returns: Transmit rate larger by logarithmically half width [pps]. + :rtype: float + """ + return current_bound / ( + 1.0 - MultipleLossRatioSearch.half_relative_width(relative_width)) + + def narrow_down_ndr_and_pdr( + self, minimum_transmit_rate, maximum_transmit_rate, + packet_loss_ratio): + """Perform initial phase, create state object, proceed with next phases. + + :param minimum_transmit_rate: Minimal target transmit rate [pps]. + :param maximum_transmit_rate: Maximal target transmit rate [pps]. + :param packet_loss_ratio: Fraction of packets lost, for PDR [1]. + :type minimum_transmit_rate: float + :type maximum_transmit_rate: float + :type packet_loss_ratio: float + :returns: Structure containing narrowed down intervals + and their measurements. + :rtype: NdrPdrResult + :raises RuntimeError: If total duration is larger than timeout. + """ + minimum_transmit_rate = float(minimum_transmit_rate) + maximum_transmit_rate = float(maximum_transmit_rate) + packet_loss_ratio = float(packet_loss_ratio) + line_measurement = self.measurer.measure( + self.initial_trial_duration, maximum_transmit_rate) + initial_width_goal = self.final_relative_width + for _ in range(self.number_of_intermediate_phases): + initial_width_goal = self.double_relative_width(initial_width_goal) + max_lo = maximum_transmit_rate * (1.0 - initial_width_goal) + mrr = max( + minimum_transmit_rate, + min(max_lo, line_measurement.receive_rate)) + mrr_measurement = self.measurer.measure( + self.initial_trial_duration, mrr) + # Attempt to get narrower width. + if mrr_measurement.loss_fraction > 0.0: + max2_lo = mrr * (1.0 - initial_width_goal) + mrr2 = min(max2_lo, mrr_measurement.receive_rate) + else: + mrr2 = mrr / (1.0 - initial_width_goal) + if mrr2 > minimum_transmit_rate and mrr2 < maximum_transmit_rate: + line_measurement = mrr_measurement + mrr_measurement = self.measurer.measure( + self.initial_trial_duration, mrr2) + if mrr2 > mrr: + buf = line_measurement + line_measurement = mrr_measurement + mrr_measurement = buf + starting_interval = ReceiveRateInterval( + mrr_measurement, line_measurement) + starting_result = NdrPdrResult(starting_interval, starting_interval) + state = self.ProgressState( + starting_result, self.number_of_intermediate_phases, + self.final_trial_duration, self.final_relative_width, + packet_loss_ratio, minimum_transmit_rate, maximum_transmit_rate) + state = self.ndrpdr(state) + return state.result + + def _measure_and_update_state(self, state, transmit_rate): + """Perform trial measurement, update bounds, return new state. + + :param state: State before this measurement. + :param transmit_rate: Target transmit rate for this measurement [pps]. + :type state: ProgressState + :type transmit_rate: float + :returns: State after the measurement. + :rtype: ProgressState + """ + # TODO: Implement https://stackoverflow.com/a/24683360 + # to avoid the string manipulation if log verbosity is too low. + logging.info("result before update: %s", state.result) + logging.debug( + "relative widths in goals: %s", state.result.width_in_goals( + self.final_relative_width)) + measurement = self.measurer.measure(state.duration, transmit_rate) + ndr_interval = self._new_interval( + state.result.ndr_interval, measurement, 0.0) + pdr_interval = self._new_interval( + state.result.pdr_interval, measurement, state.packet_loss_ratio) + state.result = NdrPdrResult(ndr_interval, pdr_interval) + return state + + @staticmethod + def _new_interval(old_interval, measurement, packet_loss_ratio): + """Return new interval with bounds updated according to the measurement. + + :param old_interval: The current interval before the measurement. + :param measurement: The new meaqsurement to take into account. + :param packet_loss_ratio: Fraction for PDR (or zero for NDR). + :type old_interval: ReceiveRateInterval + :type measurement: ReceiveRateMeasurement + :type packet_loss_ratio: float + :returns: The updated interval. + :rtype: ReceiveRateInterval + """ + old_lo, old_hi = old_interval.measured_low, old_interval.measured_high + # Priority zero: direct replace if the target Tr is the same. + if measurement.target_tr in (old_lo.target_tr, old_hi.target_tr): + if measurement.target_tr == old_lo.target_tr: + return ReceiveRateInterval(measurement, old_hi) + else: + return ReceiveRateInterval(old_lo, measurement) + # Priority one: invalid lower bound allows only one type of update. + if old_lo.loss_fraction > packet_loss_ratio: + # We can only expand down, old bound becomes valid upper one. + if measurement.target_tr < old_lo.target_tr: + return ReceiveRateInterval(measurement, old_lo) + else: + return old_interval + # Lower bound is now valid. + # Next priorities depend on target Tr. + if measurement.target_tr < old_lo.target_tr: + # Lower external measurement, relevant only + # if the new measurement has high loss rate. + if measurement.loss_fraction > packet_loss_ratio: + # Returning the broader interval as old_lo + # would be invalid upper bound. + return ReceiveRateInterval(measurement, old_hi) + elif measurement.target_tr > old_hi.target_tr: + # Upper external measurement, only relevant for invalid upper bound. + if old_hi.loss_fraction <= packet_loss_ratio: + # Old upper bound becomes valid new lower bound. + return ReceiveRateInterval(old_hi, measurement) + else: + # Internal measurement, replaced boundary + # depends on measured loss fraction. + if measurement.loss_fraction > packet_loss_ratio: + # We have found a narrow valid interval, + # regardless of whether old upper bound was valid. + return ReceiveRateInterval(old_lo, measurement) + else: + # In ideal world, we would not want to shrink interval + # if upper bound is not valid. + # In the real world, we want to shrink it for + # "invalid upper bound at maximal rate" case. + return ReceiveRateInterval(measurement, old_hi) + # Fallback, the interval is unchanged by the measurement. + return old_interval + + def ndrpdr(self, state): + """Pefrom trials for this phase. Return the new state when done. + + :param state: State before this phase. + :type state: ProgressState + :returns: The updated state. + :rtype: ProgressState + :raises RuntimeError: If total duration is larger than timeout. + """ + start_time = time.time() + if state.phases > 0: + # We need to finish preceding intermediate phases first. + saved_phases = state.phases + state.phases -= 1 + # Preceding phases have shorter duration. + saved_duration = state.duration + duration_multiplier = state.duration / self.initial_trial_duration + phase_exponent = float(state.phases) / saved_phases + state.duration = self.initial_trial_duration * math.pow( + duration_multiplier, phase_exponent) + # Shorter durations do not need that narrow widths. + saved_width = state.width_goal + state.width_goal = self.double_relative_width(state.width_goal) + # Recurse. + state = self.ndrpdr(state) + # Restore the state for current phase. + state.duration = saved_duration + state.width_goal = saved_width + state.phases = saved_phases # Not needed, but just in case. + logging.info( + "starting iterations with duration %s and relative width goal %s", + state.duration, state.width_goal) + while 1: + if time.time() > start_time + self.timeout: + raise RuntimeError("Optimized search takes too long.") + # Order of priorities: invalid bounds (nl, pl, nh, ph), + # then narrowing relative Tr widths. + # Durations are not priorities yet, + # they will settle on their own hopefully. + ndr_lo = state.result.ndr_interval.measured_low + ndr_hi = state.result.ndr_interval.measured_high + pdr_lo = state.result.pdr_interval.measured_low + pdr_hi = state.result.pdr_interval.measured_high + ndr_rel_width = max( + state.width_goal, state.result.ndr_interval.rel_tr_width) + pdr_rel_width = max( + state.width_goal, state.result.pdr_interval.rel_tr_width) + # If we are hitting maximal or minimal rate, we cannot shift, + # but we can re-measure. + if ndr_lo.loss_fraction > 0.0: + if ndr_lo.target_tr > state.minimum_transmit_rate: + new_tr = max( + state.minimum_transmit_rate, + self.double_step_down(ndr_rel_width, ndr_lo.target_tr)) + logging.info("ndr lo external %s", new_tr) + state = self._measure_and_update_state(state, new_tr) + continue + elif ndr_lo.duration < state.duration: + logging.info("ndr lo minimal re-measure") + state = self._measure_and_update_state( + state, state.minimum_transmit_rate) + continue + if pdr_lo.loss_fraction > state.packet_loss_ratio: + if pdr_lo.target_tr > state.minimum_transmit_rate: + new_tr = max( + state.minimum_transmit_rate, + self.double_step_down(pdr_rel_width, pdr_lo.target_tr)) + logging.info("pdr lo external %s", new_tr) + state = self._measure_and_update_state(state, new_tr) + continue + elif pdr_lo.duration < state.duration: + logging.info("pdr lo minimal re-measure") + state = self._measure_and_update_state( + state, state.minimum_transmit_rate) + continue + if ndr_hi.loss_fraction <= 0.0: + if ndr_hi.target_tr < state.maximum_transmit_rate: + new_tr = min( + state.maximum_transmit_rate, + self.double_step_up(ndr_rel_width, ndr_hi.target_tr)) + logging.info("ndr hi external %s", new_tr) + state = self._measure_and_update_state(state, new_tr) + continue + elif ndr_hi.duration < state.duration: + logging.info("ndr hi maximal re-measure") + state = self._measure_and_update_state( + state, state.maximum_transmit_rate) + continue + if pdr_hi.loss_fraction <= state.packet_loss_ratio: + if pdr_hi.target_tr < state.maximum_transmit_rate: + new_tr = min( + state.maximum_transmit_rate, + self.double_step_up(pdr_rel_width, pdr_hi.target_tr)) + logging.info("pdr hi external %s", new_tr) + state = self._measure_and_update_state(state, new_tr) + continue + elif pdr_hi.duration < state.duration: + logging.info("ndr hi maximal re-measure") + state = self._measure_and_update_state( + state, state.maximum_transmit_rate) + continue + # If we are hitting maximum_transmit_rate, + # it is still worth narrowing width, + # hoping large enough loss fraction will happen. + # But if we are hitting the minimal rate (at current duration), + # no additional measurement will help with that, + # so we can stop narrowing in this phase. + if (ndr_lo.target_tr <= state.minimum_transmit_rate + and ndr_lo.loss_fraction > 0.0): + ndr_rel_width = 0.0 + if (pdr_lo.target_tr <= state.minimum_transmit_rate + and pdr_lo.loss_fraction > state.packet_loss_ratio): + pdr_rel_width = 0.0 + if ndr_rel_width > state.width_goal: + # We have to narrow NDR width first, as NDR internal search + # can invalidate PDR (but not vice versa). + new_tr = self.half_step_up(ndr_rel_width, ndr_lo.target_tr) + logging.info("Bisecting for NDR at %s", new_tr) + state = self._measure_and_update_state(state, new_tr) + continue + if pdr_rel_width > state.width_goal: + # PDR iternal search. + new_tr = self.half_step_up(pdr_rel_width, pdr_lo.target_tr) + logging.info("Bisecting for PDR at %s", new_tr) + state = self._measure_and_update_state(state, new_tr) + continue + # We do not need to improve width, but there still might be + # some measurements with smaller duration. + # We need to re-measure with full duration, possibly + # creating invalid bounds to resolve (thus broadening width). + if ndr_lo.duration < state.duration: + logging.info("re-measuring NDR lower bound") + self._measure_and_update_state(state, ndr_lo.target_tr) + continue + if pdr_lo.duration < state.duration: + logging.info("re-measuring PDR lower bound") + self._measure_and_update_state(state, pdr_lo.target_tr) + continue + # Except when lower bounds have high loss fraction, in that case + # we do not need to re-measure _upper_ bounds. + if ndr_hi.duration < state.duration and ndr_rel_width > 0.0: + logging.info("re-measuring NDR upper bound") + self._measure_and_update_state(state, ndr_hi.target_tr) + continue + if pdr_hi.duration < state.duration and pdr_rel_width > 0.0: + logging.info("re-measuring PDR upper bound") + self._measure_and_update_state(state, pdr_hi.target_tr) + continue + # Widths are narrow (or lower bound minimal), bound measurements + # are long enough, we can return. + logging.info("phase done") + break + return state diff --git a/resources/libraries/python/MLRsearch/NdrPdrResult.py b/resources/libraries/python/MLRsearch/NdrPdrResult.py new file mode 100644 index 0000000000..b69a57ecbe --- /dev/null +++ b/resources/libraries/python/MLRsearch/NdrPdrResult.py @@ -0,0 +1,65 @@ +# Copyright (c) 2018 Cisco and/or its affiliates. +# 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. + +"""Module defining NdrPdrResult class.""" + +from ReceiveRateInterval import ReceiveRateInterval + + +class NdrPdrResult(object): + """Two measurement intervals, return value of search algorithms. + + Partial fraction is NOT part of the result. Pdr interval should be valid + for all partial fractions implied by the interval.""" + + def __init__(self, ndr_interval, pdr_interval): + """Store the measured intervals after checking argument types. + + :param ndr_interval: Object containing data for NDR part of the result. + :param pdr_interval: Object containing data for PDR part of the result. + :type ndr_interval: ReceiveRateInterval + :type pdr_interval: ReceiveRateInterval + """ + # TODO: Type checking is not very pythonic, + # perhaps users can fix wrong usage without it? + if not isinstance(ndr_interval, ReceiveRateInterval): + raise TypeError("ndr_interval, is not a ReceiveRateInterval: " + "{ndr!r}".format(ndr=ndr_interval)) + if not isinstance(pdr_interval, ReceiveRateInterval): + raise TypeError("pdr_interval, is not a ReceiveRateInterval: " + "{pdr!r}".format(pdr=pdr_interval)) + self.ndr_interval = ndr_interval + self.pdr_interval = pdr_interval + + def width_in_goals(self, relative_width_goal): + """Return a debug string related to current widths in logarithmic scale. + + :param relative_width_goal: Upper bound times this is the goal + difference between upper bound and lower bound. + :type relative_width_goal: float + :returns: Message containing NDR and PDR widths in goals. + :rtype: str + """ + return "ndr {ndr_in_goals}; pdr {pdr_in_goals}".format( + ndr_in_goals=self.ndr_interval.width_in_goals(relative_width_goal), + pdr_in_goals=self.pdr_interval.width_in_goals(relative_width_goal)) + + def __str__(self): + """Return string as tuple of named values.""" + return "NDR={ndr!s};PDR={pdr!s}".format( + ndr=self.ndr_interval, pdr=self.pdr_interval) + + def __repr__(self): + """Return string evaluable as a constructor call.""" + return "NdrPdrResult(ndr_interval={ndr!r},pdr_interval={pdr!r})".format( + ndr=self.ndr_interval, pdr=self.pdr_interval) diff --git a/resources/libraries/python/MLRsearch/ReceiveRateInterval.py b/resources/libraries/python/MLRsearch/ReceiveRateInterval.py new file mode 100644 index 0000000000..05e0f10013 --- /dev/null +++ b/resources/libraries/python/MLRsearch/ReceiveRateInterval.py @@ -0,0 +1,84 @@ +# Copyright (c) 2018 Cisco and/or its affiliates. +# 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. + +"""Module defining ReceiveRateInterval class.""" + +import math + +from ReceiveRateMeasurement import ReceiveRateMeasurement + + +class ReceiveRateInterval(object): + """Structure defining two Rr measurements, and their relation.""" + + def __init__(self, measured_low, measured_high): + """Store the bound measurements after checking argument types. + + :param measured_low: Measurement for the lower bound. + :param measured_high: Measurement for the upper bound. + :type measured_low: ReceiveRateMeasurement + :type measured_high: ReceiveRateMeasurement + """ + # TODO: Type checking is not very pythonic, + # perhaps users can fix wrong usage without it? + if not isinstance(measured_low, ReceiveRateMeasurement): + raise TypeError("measured_low is not a ReceiveRateMeasurement: " + "{low!r}".format(low=measured_low)) + if not isinstance(measured_high, ReceiveRateMeasurement): + raise TypeError("measured_high is not a ReceiveRateMeasurement: " + "{high!r}".format(high=measured_high)) + self.measured_low = measured_low + self.measured_high = measured_high + # Declare secondary quantities to appease pylint. + self.abs_tr_width = None + """Absolute width of target transmit rate. Upper minus lower.""" + self.rel_tr_width = None + """Relative width of target transmit rate. Absolute divided by upper.""" + self.sort() + + def sort(self): + """Sort bounds by target Tr, compute secondary quantities.""" + if self.measured_low.target_tr > self.measured_high.target_tr: + self.measured_low, self.measured_high = ( + self.measured_high, self.measured_low) + self.abs_tr_width = ( + self.measured_high.target_tr - self.measured_low.target_tr) + self.rel_tr_width = self.abs_tr_width / self.measured_high.target_tr + + def width_in_goals(self, relative_width_goal): + """Return float value. + + Relative width goal is some (negative) value on logarithmic scale. + Current relative width is another logarithmic value. + Return the latter divided by the former. + This is useful when investigating how did surprising widths come to be. + + :param relative_width_goal: Upper bound times this is the goal + difference between upper bound and lower bound. + :type relative_width_goal: float + :returns: Current width as logarithmic multiple of goal width [1]. + :rtype: float + """ + return math.log(1.0 - self.rel_tr_width) / math.log( + 1.0 - relative_width_goal) + + def __str__(self): + """Return string as half-open interval.""" + return "[{low!s};{high!s})".format( + low=self.measured_low, high=self.measured_high) + + def __repr__(self): + """Return string evaluable as a constructor call.""" + return ("ReceiveRateInterval(measured_low={low!r}" + ",measured_high={high!r})".format( + low=self.measured_low, high=self.measured_high)) diff --git a/resources/libraries/python/MLRsearch/ReceiveRateMeasurement.py b/resources/libraries/python/MLRsearch/ReceiveRateMeasurement.py new file mode 100644 index 0000000000..d052ebd3bf --- /dev/null +++ b/resources/libraries/python/MLRsearch/ReceiveRateMeasurement.py @@ -0,0 +1,54 @@ +# Copyright (c) 2018 Cisco and/or its affiliates. +# 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. + +"""Module defining ReceiveRateMeasurement class.""" + + +class ReceiveRateMeasurement(object): + """Structure defining the result of single Rr measurement.""" + + def __init__(self, duration, target_tr, transmit_count, loss_count): + """Constructor, normalize primary and compute secondary quantities. + + :param duration: Measurement duration [s]. + :param target_tr: Target transmit rate [pps]. + If bidirectional traffic is measured, this is bidirectional rate. + :param transmit_count: Number of packets transmitted [1]. + :param loss_count: Number of packets transmitted but not received [1]. + :type duration: float + :type target_tr: float + :type transmit_count: int + :type loss_count: int + """ + self.duration = float(duration) + self.target_tr = float(target_tr) + self.transmit_count = int(transmit_count) + self.loss_count = int(loss_count) + self.receive_count = transmit_count - loss_count + self.transmit_rate = transmit_count / self.duration + self.loss_rate = loss_count / self.duration + self.receive_rate = self.receive_count / self.duration + self.loss_fraction = float(self.loss_count) / self.transmit_count + # TODO: Do we want to store also the real time (duration + overhead)? + + def __str__(self): + """Return string reporting input and loss fraction.""" + return "d={dur!s},Tr={rate!s},Df={frac!s}".format( + dur=self.duration, rate=self.target_tr, frac=self.loss_fraction) + + def __repr__(self): + """Return string evaluable as a constructor call.""" + return ("ReceiveRateMeasurement(duration={dur!r},target_tr={rate!r}" + ",transmit_count={trans!r},loss_count={loss!r})".format( + dur=self.duration, rate=self.target_tr, + trans=self.transmit_count, loss=self.loss_count)) diff --git a/resources/libraries/python/MLRsearch/__init__.py b/resources/libraries/python/MLRsearch/__init__.py new file mode 100644 index 0000000000..4cc8158397 --- /dev/null +++ b/resources/libraries/python/MLRsearch/__init__.py @@ -0,0 +1,16 @@ +# Copyright (c) 2018 Cisco and/or its affiliates. +# 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. + +""" +__init__ file for Python package "MLRsearch" +""" |