| 1 | package de.uka.ipd.sdq.scheduler.loaddistribution.balancers; |
| 2 | |
| 3 | import java.util.List; |
| 4 | |
| 5 | import de.uka.ipd.sdq.scheduler.SchedulerModel; |
| 6 | import de.uka.ipd.sdq.scheduler.processes.IActiveProcess; |
| 7 | import de.uka.ipd.sdq.scheduler.processes.impl.PreemptiveProcess; |
| 8 | import de.uka.ipd.sdq.scheduler.resources.IResourceInstance; |
| 9 | |
| 10 | /** |
| 11 | * Ensures that the load of two resource instances does not differ more than |
| 12 | * 'threshold'. The threshold is a relative value between 0 and 1. If 0 the load |
| 13 | * of both instances must be equal, if 1 the load of both instances is never |
| 14 | * balanced. |
| 15 | * |
| 16 | * @author jens.happe |
| 17 | * |
| 18 | */ |
| 19 | public class ToThresholdBalancer extends AbstractLoadBalancer { |
| 20 | |
| 21 | private SchedulerModel model; |
| 22 | private double last_balanced = 0; |
| 23 | private int threshold; |
| 24 | |
| 25 | public ToThresholdBalancer(SchedulerModel model, double balancing_interval, |
| 26 | boolean prio_increasing, boolean queue_ascending, int threshold) { |
| 27 | super(balancing_interval, prio_increasing, queue_ascending); |
| 28 | this.model = model; |
| 29 | this.threshold = threshold; |
| 30 | } |
| 31 | |
| 32 | public void activelyBalance(IResourceInstance instance) { |
| 33 | double now = model.getSimulationControl().getCurrentSimulationTime(); |
| 34 | if ((now - last_balanced) > balancing_interval) { |
| 35 | balance(getBusiest(), getLaziest()); |
| 36 | last_balanced = now; |
| 37 | } |
| 38 | } |
| 39 | |
| 40 | public void onFork(IResourceInstance instance) { |
| 41 | balance(instance, getLaziest()); |
| 42 | } |
| 43 | |
| 44 | public void onSleep(IResourceInstance instance) { |
| 45 | if (load(instance) == 0) { |
| 46 | balance(getBusiest(), instance); |
| 47 | } |
| 48 | } |
| 49 | |
| 50 | public void onTerminate(IResourceInstance instance) { |
| 51 | if (load(instance) == 0) { |
| 52 | balance(getBusiest(), instance); |
| 53 | } |
| 54 | } |
| 55 | |
| 56 | public void onWake(IResourceInstance instance) { |
| 57 | balance(instance,getLaziest()); |
| 58 | } |
| 59 | |
| 60 | private void balance(IResourceInstance sender, IResourceInstance receiver) { |
| 61 | if (sender != null && receiver != null) { |
| 62 | if (!sender.equals(receiver)) { |
| 63 | int distance = load(sender) - load(receiver); |
| 64 | if (distance > threshold) { |
| 65 | List<IActiveProcess> processList = queue_holder |
| 66 | .getRunQueueFor(sender).identifyMovableProcesses( |
| 67 | receiver, prio_increasing, queue_ascending, |
| 68 | distance / 2); |
| 69 | for (IActiveProcess process : processList) { |
| 70 | fakeThreadLoadBalancing(process, sender, receiver); |
| 71 | //queue_holder.move(process, sender, receiver); |
| 72 | } |
| 73 | } |
| 74 | } |
| 75 | } |
| 76 | } |
| 77 | |
| 78 | /** |
| 79 | * From the beautiful method name, the careful reader might have guessed |
| 80 | * that things get a bit, well, messy at this point. Fact is, that Windows |
| 81 | * (or Java ?) balances threads differently from processes by simply |
| 82 | * changing the association between light weight processes and (user level) |
| 83 | * threads. That makes things a bit difficult as heavy weight and light |
| 84 | * weight processes as well as threads would have to be reflected in the |
| 85 | * model. |
| 86 | * |
| 87 | * Sorry for anyone responsible fixing this, but I hope this comment helps. |
| 88 | * Further discussion can be found in class 'SimResourceInstance' at |
| 89 | * variable 'last_running_process'. |
| 90 | * |
| 91 | * @param process |
| 92 | * moved process |
| 93 | * @param sender |
| 94 | * sending resource instance |
| 95 | * @param receiver |
| 96 | * receiving resource instance |
| 97 | */ |
| 98 | private void fakeThreadLoadBalancing(IActiveProcess process, |
| 99 | IResourceInstance sender, IResourceInstance receiver) { |
| 100 | if (receiver.getLastRunningProcess() != null) { |
| 101 | PreemptiveProcess p = (PreemptiveProcess) receiver.getLastRunningProcess(); |
| 102 | |
| 103 | // here we assume that the waiting process is in fact a thread that |
| 104 | // belongs to the same process as the thread (process) to move. |
| 105 | // the following assigns the waiting thread to the resource of |
| 106 | // the sender. This fakes the switch of LWPs. |
| 107 | if (p.isWaiting()) { |
| 108 | p.setLastInstance(process.getLastInstance()); |
| 109 | p.setIdealInstance(process.getIdealInstance()); |
| 110 | } |
| 111 | } |
| 112 | queue_holder.move(process, sender, receiver); |
| 113 | } |
| 114 | |
| 115 | |
| 116 | private IResourceInstance getLaziest() { |
| 117 | IResourceInstance result = null; |
| 118 | for (IResourceInstance ri : queue_holder.getResourceInstances()) { |
| 119 | if (result == null || load(ri) < load(result)) { |
| 120 | result = ri; |
| 121 | } |
| 122 | } |
| 123 | return result; |
| 124 | } |
| 125 | |
| 126 | private IResourceInstance getBusiest() { |
| 127 | IResourceInstance result = null; |
| 128 | for (IResourceInstance ri : queue_holder.getResourceInstances()) { |
| 129 | if (result == null || load(ri) > load(result)) { |
| 130 | result = ri; |
| 131 | } |
| 132 | } |
| 133 | return result; |
| 134 | } |
| 135 | } |