/*
* Copyright (c) Fabien Hermenier
*
* This file is part of Entropy.
*
* Entropy is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Entropy is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with Entropy. If not, see <http://www.gnu.org/licenses/>.
*/
package entropy.plan.choco.search;
import choco.kernel.common.logging.ChocoLogging;
import choco.kernel.common.util.iterators.DisposableIntIterator;
import choco.kernel.solver.search.ValSelector;
import choco.kernel.solver.variables.integer.IntDomainVar;
import entropy.configuration.ManagedElementSet;
import entropy.configuration.VirtualMachine;
import entropy.plan.choco.DefaultReconfigurationProblem;
import entropy.plan.choco.ReconfigurationProblem;
import entropy.plan.choco.actionModel.MigratableActionModel;
import entropy.plan.choco.actionModel.ResumeActionModel;
import entropy.plan.choco.actionModel.VirtualMachineActionModel;
import entropy.plan.choco.constraint.pack.SatisfyDemandingSliceHeights;
import gnu.trove.TLongIntHashMap;
/**
* A heuristic to try to assign the virtual machines to migrate
* or to resume to its current (or previous) location.
* If it is not possible, it consider the current residual capacity of the nodes
* to choose the one to test.
*
* @author Fabien Hermenier
*/
public class StayFirstSelector2 implements ValSelector<IntDomainVar> {
public enum Option {
wfMem, wfCPU, bfMem, bfCPU
}
private Option opt;
private SatisfyDemandingSliceHeights pack;
/**
* The previous location of the running VMs.
*/
private TLongIntHashMap oldLocation;
/**
* Build a selector for a specific solver.
*
* @param s the solver
* @param pack the pack constraint
* @param o the option to customize the heuristic
*/
public StayFirstSelector2(ReconfigurationProblem s, SatisfyDemandingSliceHeights pack, Option o) {
this.opt = o;
this.pack = pack;
ManagedElementSet<VirtualMachine> relocalisables = s.getFutureRunnings();
this.oldLocation = new TLongIntHashMap(relocalisables.size());
/* for (VirtualMachineActionModel a : s.getAssociatedActions(relocalisables)) {
if (a.getClass() == MigratableActionModel.class) {
oldLocation.put(a.getDemandingSlice().hoster().getIndex(), s.getNode(s.getSourceConfiguration().getLocation(a.getVirtualMachine())));
} else if (a.getClass() == ResumeActionModel.class) {
oldLocation.put(a.getDemandingSlice().hoster().getIndex(), s.getNode(s.getSourceConfiguration().getLocation(a.getVirtualMachine())));
}
}*/
for (VirtualMachine vm : relocalisables) {
int idx = s.getVirtualMachine(vm);
VirtualMachineActionModel a = ((DefaultReconfigurationProblem) s).getAssociatedVirtualMachineAction(idx);
if (a.getClass() == MigratableActionModel.class || a.getClass() == ResumeActionModel.class) {
oldLocation.put(a.getDemandingSlice().hoster().getIndex(), ((DefaultReconfigurationProblem) s).getLocation(idx));
}
}
}
/**
* Get the bin with the maximum remaining space.
*
* @param place the hoster variable of the slice to place.
* @param dim 0 for the CPU dimension, 1 for the memory dimension
* @return {@code -1} if no host is available, otherwise the index of the node.
*/
private int worstFit(IntDomainVar place, int dim) {
DisposableIntIterator ite = place.getDomain().getIterator();
int maxIdx = -1;
int maxVal = -1;
try {
while (ite.hasNext()) {
int bIdx = ite.next();
int bVal = dim == 0 ? pack.getRemainingCPU(bIdx) : pack.getRemainingMemory(bIdx);
//Plan.logger.debug("Node N" + bIdx + " free=" + bVal);
if (bVal > maxVal) {
maxVal = bVal;
maxIdx = bIdx;
}
}
} finally {
ite.dispose();
}
//Plan.logger.debug("Choose N" + maxIdx);
return maxIdx;
}
/**
* Get the bin with the minimum remaining space.
*
* @param place the hoster variable of the slice to place.
* @param dim 0 for the CPU dimension, 1 for the memory dimension
* @return {@code -1} if no host is available, otherwise the index of the node.
*/
private int bestFit(IntDomainVar place, int dim) {
//DisposableIntIterator ite = place.getDomain().getIterator();
int minIdx = -1;
int minVal = Integer.MAX_VALUE;
/* while (ite.hasNext()) {
int bIdx = ite.next();
int bVal = pack.getRemainingSpace(bIdx);
// Plan.logger.debug("Node N" + bIdx + " free=" + bVal);
if (bVal < minVal) {
minVal = bVal;
minIdx = bIdx;
}
} */
for (int bIdx = place.getInf(); bIdx <= place.getSup(); bIdx = place.getDomain().getNextValue(bIdx)) {
int bVal = dim == 0 ? pack.getRemainingCPU(bIdx) : pack.getRemainingMemory(bIdx);
// Plan.logger.debug("Node N" + bIdx + " free=" + bVal);
if (bVal < minVal) {
minVal = bVal;
minIdx = bIdx;
}
}
//ite.dispose();
//Plan.logger.debug("Choose N" + minIdx);
return minIdx;
}
@Override
public int getBestVal(IntDomainVar var) {
int val = this.oldLocation.get(var.getIndex());
//Check wether the VM can stay on the same node.
if (this.oldLocation.containsKey(var.getIndex()) && var.canBeInstantiatedTo(val)) {
ChocoLogging.getSearchLogger().finest(var.pretty() + " stay on " + val);
return val;
}
int to;
switch (opt) {
case wfCPU:
to = worstFit(var, 0);
break;
case wfMem:
to = worstFit(var, 1);
break;
case bfCPU:
to = bestFit(var, 0);
break;
case bfMem:
to = bestFit(var, 1);
break;
default:
to = var.getInf();
}
ChocoLogging.getSearchLogger().finest(var.pretty() + " move from " + val + " to " + to);
return to;
}
}