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Diffstat (limited to 'resources/libraries/python/DropRateSearch.py')
| -rw-r--r-- | resources/libraries/python/DropRateSearch.py | 301 |
1 files changed, 301 insertions, 0 deletions
diff --git a/resources/libraries/python/DropRateSearch.py b/resources/libraries/python/DropRateSearch.py new file mode 100644 index 0000000000..4bbf16c1a2 --- /dev/null +++ b/resources/libraries/python/DropRateSearch.py @@ -0,0 +1,301 @@ +# Copyright (c) 2016 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. + +"""Drop rate search algorithms""" + +from abc import ABCMeta, abstractmethod +from enum import Enum, unique + +@unique +class SearchDirection(Enum): + """Direction of linear search""" + + TOP_DOWN = 1 + BOTTOM_UP = 2 + +@unique +class SearchResults(Enum): + """Result of the drop rate search""" + + SUCCESS = 1 + FAILURE = 2 + SUSPICIOUS = 3 + +@unique +class RateType(Enum): + """Type of rate units""" + + PERCENTAGE = 1 + PACKETS_PER_SECOND = 2 + BITS_PER_SECOND = 3 + +@unique +class LossAcceptanceType(Enum): + """Type of the loss acceptance criteria""" + + FRAMES = 1 + PERCENTAGE = 2 + +class DropRateSearch(object): + """Abstract class with search algorithm implementation""" + + __metaclass__ = ABCMeta + + def __init__(self): + #duration of traffic run (binary, linear) + self._duration = 60 + #initial start rate (binary, linear) + self._rate_start = 100 + #step of the linear search, unit: RateType (self._rate_type) + self._rate_linear_step = 10 + #linear search direction, permitted values: SearchDirection + self._search_linear_direction = SearchDirection.TOP_DOWN + #upper limit of search, unit: RateType (self._rate_type) + self._rate_max = 100 + #lower limit of search, unit: RateType (self._rate_type) + self._rate_min = 1 + #permitted values: RateType + self._rate_type = RateType.PERCENTAGE + #accepted loss during search, units: LossAcceptanceType + self._loss_acceptance = 0 + #permitted values: LossAcceptanceType + self._loss_acceptance_type = LossAcceptanceType.FRAMES + #size of frames to send + self._frame_size = "64" + #binary convergence criterium type is self._rate_type + self._binary_convergence_threshhold = "0.01" + #numbers of traffic runs during one rate step + self._max_attempts = 1 + + #result of search + self._search_result = None + self._search_result_rate = None + + @abstractmethod + def measure_loss(self, rate, frame_size, loss_acceptance, + loss_acceptance_type, traffic_type): + """Send traffic from TG and measure count of dropped frames + + :param rate: offered traffic load + :param frame_size: size of frame + :param loss_acceptance: permitted drop ratio or frames count + :param loss_acceptance_type: type of permitted loss + :param traffic_type: traffic profile ([2,3]-node-L[2,3], ...) + :type rate: int + :type frame_size: str + :type loss_acceptance: float + :type loss_acceptance_type: LossAcceptanceType + :type traffic_type: str + :return: drop threshhold exceeded? (True/False) + :rtype bool + """ + pass + + def set_search_rate_boundaries(self, max_rate, min_rate): + """Set search boundaries: min,max + + :param max_rate: upper value of search boundaries + :param min_rate: lower value of search boundaries + :type max_rate: float + :type min_rate: float + :return: nothing + """ + if float(min_rate) <= 0: + raise ValueError("min_rate must be higher than 0") + elif float(min_rate) > float(max_rate): + raise ValueError("min_rate must be lower than max_rate") + else: + self._rate_max = float(max_rate) + self._rate_min = float(min_rate) + + def set_search_linear_step(self, step_rate): + """Set step size for linear search + + :param step_rate: linear search step size + :type step_rate: float + :return: nothing + """ + self._rate_linear_step = float(step_rate) + + def set_search_rate_type_percentage(self): + """Set rate type to percentage of linerate + + :return: nothing + """ + self._set_search_rate_type(RateType.PERCENTAGE) + + def set_search_rate_type_bps(self): + """Set rate type to bits per second + + :return: nothing + """ + self._set_search_rate_type(RateType.BITS_PER_SECOND) + + def set_search_rate_type_pps(self): + """Set rate type to packets per second + + :return: nothing + """ + self._set_search_rate_type(RateType.PACKETS_PER_SECOND) + + def _set_search_rate_type(self, rate_type): + """Set rate type to one of RateType-s + + :param rate_type: type of rate to set + :type rate_type: RateType + :return: nothing + """ + if rate_type not in RateType: + raise Exception("rate_type unknown: {}".format(rate_type)) + else: + self._rate_type = rate_type + + def set_search_frame_size(self, frame_size): + """Set size of frames to send + + :param frame_size: size of frames + :type frame_size: str + :return: nothing + """ + self._frame_size = frame_size + + def set_duration(self, duration): + """Set the duration of single traffic run + + :param duration: number of seconds for traffic to run + :type duration: int + :return: nothing + """ + self._duration = int(duration) + + def get_duration(self): + """Return configured duration of single traffic run + + :return: number of seconds for traffic to run + :rtype: int + """ + return self._duration + + def get_rate_type_str(self): + """Return rate type representation + + :return: string representation of rate type + :rtype: str + """ + if self._rate_type == RateType.PERCENTAGE: + return "%" + elif self._rate_type == RateType.BITS_PER_SECOND: + return "bps" + elif self._rate_type == RateType.PACKETS_PER_SECOND: + return "pps" + else: + raise ValueError("RateType unknown") + + def linear_search(self, start_rate, traffic_type): + """Linear search of rate with loss below acceptance criteria + + :param start_rate: initial rate + :param traffic_type: traffic profile + :type start_rate: float + :param traffic_type: str + :return: nothing + """ + + if not self._rate_min <= float(start_rate) <= self._rate_max: + raise ValueError("Start rate is not in min,max range") + + rate = float(start_rate) + #the last but one step + prev_rate = None + + #linear search + while True: + res = self.measure_loss(rate, self._frame_size, + self._loss_acceptance, + self._loss_acceptance_type, + traffic_type) + if self._search_linear_direction == SearchDirection.BOTTOM_UP: + #loss occured and it was above acceptance criteria + if res == False: + #if this is first run then we didn't find drop rate + if prev_rate == None: + self._search_result = SearchResults.FAILURE + self._search_result_rate = None + return + # else we found the rate, which is value from previous run + else: + self._search_result = SearchResults.SUCCESS + self._search_result_rate = prev_rate + return + #there was no loss / loss below acceptance criteria + elif res == True: + prev_rate = rate + rate += self._rate_linear_step + if rate > self._rate_max: + if prev_rate != self._rate_max: + #one last step with rate set to _rate_max + rate = self._rate_max + continue + else: + self._search_result = SearchResults.SUCCESS + self._search_result_rate = prev_rate + return + else: + continue + else: + raise RuntimeError("Unknown search result") + + elif self._search_linear_direction == SearchDirection.TOP_DOWN: + #loss occured, decrease rate + if res == False: + prev_rate = rate + rate -= self._rate_linear_step + if rate < self._rate_min: + if prev_rate != self._rate_min: + #one last step with rate set to _rate_min + rate = self._rate_min + continue + else: + self._search_result = SearchResults.FAILURE + self._search_result_rate = None + return + else: + continue + #no loss => non/partial drop rate found + elif res == True: + self._search_result = SearchResults.SUCCESS + self._search_result_rate = rate + return + else: + raise RuntimeError("Unknown search result") + else: + raise Exception("Unknown search direction") + + raise Exception("Wrong codepath") + + def verify_search_result(self): + """Fail if search was not successful + + :return: result rate + :rtype: float + """ + if self._search_result == SearchResults.FAILURE: + raise Exception('Search FAILED') + elif self._search_result in [SearchResults.SUCCESS, SearchResults.SUSPICIOUS]: + return self._search_result_rate + + def binary_search(self): + raise NotImplementedError + + def combined_search(self): + raise NotImplementedError |