31 lines
2 KiB
ReStructuredText
31 lines
2 KiB
ReStructuredText
..
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Copyright 2014 Modelling, Simulation and Design Lab (MSDL) at
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McGill University and the University of Antwerp (http://msdl.cs.mcgill.ca/)
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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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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Activity Tracking
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=================
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Activity tracking will perform the most generic approach available: measuring the time every transition function takes, accumulating all these values and calculating the complete load of the node.
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When using the *basic boundary relocator*, the current allocation will be mutated in such a way that every node gets approximately the same load. Sometimes this will not yield decent results, since the approach is too general and uses a greedy algorithm. It should therefore only be used in very simple situations where the number of possible mutations is rather limited. A simple example of this is a queue which has only one input and one output port.
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The *basic boundary relocator* takes a single argument: the swappiness. This simply defines what threshold to use for 'unacceptable load distribution'. A swappiness of 2 for example, will only try to offload nodes that have an activity twice as big as the average activity. Setting a too low swappiness will cause many (often unnecessary) relocations, while setting a too high swappiness will prevent relocations completely.
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To start a distributed simulation with *general activity tracking*, the configuration is::
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sim = Simulator(CQueue())
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swappiness = 1.3
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sim.setActivityRelocatorBasicBoundary(swappiness)
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sim.simulate()
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