Performance updates (#314)

21 files changed, 288 insertions, 348 deletions

diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/cpu/SimCpu.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/cpu/SimCpu.java
index a9edaa97..fadfc4d6 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/cpu/SimCpu.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/cpu/SimCpu.java
@@ -22,11 +22,13 @@
 
 package org.opendc.simulator.compute.cpu;
 
+import java.util.List;
+import java.util.Map;
 import org.opendc.simulator.compute.machine.PerformanceCounters;
 import org.opendc.simulator.compute.models.CpuModel;
+import org.opendc.simulator.engine.engine.FlowEngine;
 import org.opendc.simulator.engine.graph.FlowConsumer;
 import org.opendc.simulator.engine.graph.FlowEdge;
-import org.opendc.simulator.engine.graph.FlowGraph;
 import org.opendc.simulator.engine.graph.FlowNode;
 import org.opendc.simulator.engine.graph.FlowSupplier;
 
@@ -102,15 +104,15 @@ public final class SimCpu extends FlowNode implements FlowSupplier, FlowConsumer
     // Constructors
     ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
-    public SimCpu(FlowGraph graph, CpuModel cpuModel, CpuPowerModel powerModel, int id) {
-        super(graph);
+    public SimCpu(FlowEngine engine, CpuModel cpuModel, CpuPowerModel powerModel, int id) {
+        super(engine);
         this.cpuModel = cpuModel;
         this.maxCapacity = this.cpuModel.getTotalCapacity();
 
         // TODO: connect this to the front-end
         this.cpuPowerModel = powerModel;
 
-        this.lastCounterUpdate = graph.getEngine().getClock().millis();
+        this.lastCounterUpdate = clock.millis();
 
         this.cpuFrequencyInv = 1 / this.maxCapacity;
     }
@@ -255,4 +257,11 @@ public final class SimCpu extends FlowNode implements FlowSupplier, FlowConsumer
         this.psuEdge = null;
         this.invalidate();
     }
+
+    @Override
+    public Map<FlowEdge.NodeType, List<FlowEdge>> getConnectedEdges() {
+        return Map.of(
+                FlowEdge.NodeType.CONSUMING, List.of(this.psuEdge),
+                FlowEdge.NodeType.SUPPLYING, List.of(this.distributorEdge));
+    }
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/machine/SimMachine.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/machine/SimMachine.java
index dab0c421..55a5eb42 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/machine/SimMachine.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/machine/SimMachine.java
@@ -29,17 +29,19 @@ import org.opendc.simulator.compute.cpu.SimCpu;
 import org.opendc.simulator.compute.memory.Memory;
 import org.opendc.simulator.compute.models.MachineModel;
 import org.opendc.simulator.compute.power.SimPsu;
+import org.opendc.simulator.compute.workload.ChainWorkload;
+import org.opendc.simulator.compute.workload.SimChainWorkload;
 import org.opendc.simulator.compute.workload.SimWorkload;
-import org.opendc.simulator.compute.workload.Workload;
+import org.opendc.simulator.engine.engine.FlowEngine;
 import org.opendc.simulator.engine.graph.FlowDistributor;
-import org.opendc.simulator.engine.graph.FlowGraph;
+import org.opendc.simulator.engine.graph.FlowEdge;
 
 /**
  * A machine that is able to execute {@link SimWorkload} objects.
  */
 public class SimMachine {
     private final MachineModel machineModel;
-    private final FlowGraph graph;
+    private final FlowEngine engine;
 
     private final InstantSource clock;
 
@@ -62,8 +64,8 @@ public class SimMachine {
         return machineModel;
     }
 
-    public FlowGraph getGraph() {
-        return graph;
+    public FlowEngine getEngine() {
+        return engine;
     }
 
     public InstantSource getClock() {
@@ -112,29 +114,30 @@ public class SimMachine {
     ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
     public SimMachine(
-            FlowGraph graph,
+            FlowEngine engine,
             MachineModel machineModel,
             FlowDistributor powerDistributor,
             CpuPowerModel cpuPowerModel,
             Consumer<Exception> completion) {
-        this.graph = graph;
+        this.engine = engine;
         this.machineModel = machineModel;
-        this.clock = graph.getEngine().getClock();
+        this.clock = engine.getClock();
 
         // Create the psu and cpu and connect them
-        this.psu = new SimPsu(graph);
+        this.psu = new SimPsu(engine);
 
-        graph.addEdge(this.psu, powerDistributor);
+        new FlowEdge(this.psu, powerDistributor);
 
-        this.cpu = new SimCpu(graph, this.machineModel.getCpuModel(), cpuPowerModel, 0);
+        this.cpu = new SimCpu(engine, this.machineModel.getCpuModel(), cpuPowerModel, 0);
 
-        graph.addEdge(this.cpu, this.psu);
+        new FlowEdge(this.cpu, this.psu);
 
-        this.memory = new Memory(graph, this.machineModel.getMemory());
+        this.memory = new Memory(engine, this.machineModel.getMemory());
 
         // Create a FlowDistributor and add the cpu as supplier
-        this.cpuDistributor = new FlowDistributor(this.graph);
-        graph.addEdge(this.cpuDistributor, this.cpu);
+        this.cpuDistributor = new FlowDistributor(engine);
+
+        new FlowEdge(this.cpuDistributor, this.cpu);
 
         this.completion = completion;
     }
@@ -147,13 +150,13 @@ public class SimMachine {
      * Close all related hardware
      */
     public void shutdown(Exception cause) {
-        this.graph.removeNode(this.psu);
+        this.psu.closeNode();
         this.psu = null;
 
-        this.graph.removeNode(this.cpu);
+        this.cpu.closeNode();
         this.cpu = null;
 
-        this.graph.removeNode(this.cpuDistributor);
+        this.cpuDistributor.closeNode();
         this.cpuDistributor = null;
 
         this.memory = null;
@@ -181,11 +184,7 @@ public class SimMachine {
      * @param completion
      * @return
      */
-    public VirtualMachine startWorkload(Workload workload, Consumer<Exception> completion) {
-        final VirtualMachine vm = new VirtualMachine(this);
-
-        vm.startWorkload(workload, completion);
-
-        return vm;
+    public SimChainWorkload startWorkload(ChainWorkload workload, Consumer<Exception> completion) {
+        return (SimChainWorkload) workload.startWorkload(this.cpuDistributor, this, completion);
     }
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/machine/VirtualMachine.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/machine/VirtualMachine.java
deleted file mode 100644
index 1946eecb..00000000
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/machine/VirtualMachine.java
+++ /dev/null
@@ -1,240 +0,0 @@
-/*
- * Copyright (c) 2024 AtLarge Research
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
-package org.opendc.simulator.compute.machine;
-
-import java.util.function.Consumer;
-import org.opendc.simulator.compute.cpu.SimCpu;
-import org.opendc.simulator.compute.workload.SimWorkload;
-import org.opendc.simulator.compute.workload.Workload;
-import org.opendc.simulator.engine.graph.FlowConsumer;
-import org.opendc.simulator.engine.graph.FlowEdge;
-import org.opendc.simulator.engine.graph.FlowGraph;
-import org.opendc.simulator.engine.graph.FlowNode;
-import org.opendc.simulator.engine.graph.FlowSupplier;
-
-/*
-  A virtual Machine created to run a single workload
-*/
-public class VirtualMachine extends FlowNode implements FlowConsumer, FlowSupplier {
-    private final SimMachine machine;
-
-    private SimWorkload activeWorkload;
-
-    private long lastUpdate;
-    private final double d;
-
-    private FlowEdge cpuEdge; // The edge to the cpu
-    private FlowEdge workloadEdge; // The edge to the workload
-
-    private double cpuDemand;
-    private double cpuSupply;
-    private double cpuCapacity;
-
-    private PerformanceCounters performanceCounters = new PerformanceCounters();
-
-    private Consumer<Exception> completion;
-
-    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-    // Basic Getters and Setters
-    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-
-    public PerformanceCounters getPerformanceCounters() {
-        return performanceCounters;
-    }
-
-    public SimWorkload getActiveWorkload() {
-        return activeWorkload;
-    }
-
-    public double getDemand() {
-        return cpuDemand;
-    }
-
-    public void setDemand(double demand) {
-        this.cpuDemand = demand;
-    }
-
-    public double getCpuCapacity() {
-        return cpuCapacity;
-    }
-
-    public void setCpuCapacity(double cpuCapacity) {
-        this.cpuCapacity = cpuCapacity;
-    }
-
-    public FlowGraph getGraph() {
-        return this.parentGraph;
-    }
-
-    public SimCpu getCpu() {
-        return machine.getCpu();
-    }
-
-    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-    // Constructors
-    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-
-    public VirtualMachine(SimMachine machine) {
-        super(machine.getGraph());
-        this.machine = machine;
-        this.clock = this.machine.getClock();
-
-        this.parentGraph = machine.getGraph();
-        this.parentGraph.addEdge(this, this.machine.getCpuDistributor());
-
-        this.lastUpdate = clock.millis();
-        this.lastUpdate = clock.millis();
-
-        this.d = 1 / machine.getCpu().getFrequency();
-    }
-
-    public void shutdown() {
-        this.shutdown(null);
-    }
-
-    public void shutdown(Exception cause) {
-        if (this.nodeState == NodeState.CLOSED) {
-            return;
-        }
-
-        super.closeNode();
-
-        this.activeWorkload = null;
-        this.performanceCounters = null;
-
-        this.completion.accept(cause);
-    }
-
-    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-    // Workload related functionality
-    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-
-    public void startWorkload(Workload workload, Consumer<Exception> completion) {
-        this.completion = completion;
-        this.activeWorkload = workload.startWorkload(this, this.clock.millis());
-    }
-
-    public void updateCounters(long now) {
-        long lastUpdate = this.lastUpdate;
-        this.lastUpdate = now;
-        long delta = now - lastUpdate;
-
-        if (delta > 0) {
-            final double factor = this.d * delta;
-
-            this.performanceCounters.addCpuActiveTime(Math.round(this.cpuSupply * factor));
-            this.performanceCounters.setCpuIdleTime(Math.round((this.cpuCapacity - this.cpuSupply) * factor));
-            this.performanceCounters.addCpuStealTime(Math.round((this.cpuDemand - this.cpuSupply) * factor));
-        }
-
-        this.performanceCounters.setCpuDemand(this.cpuDemand);
-        this.performanceCounters.setCpuSupply(this.cpuSupply);
-        this.performanceCounters.setCpuCapacity(this.cpuCapacity);
-    }
-
-    @Override
-    public long onUpdate(long now) {
-        updateCounters(now);
-
-        return Long.MAX_VALUE;
-    }
-
-    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-    // FlowGraph Related functionality
-    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
-
-    /**
-     * Add an edge to the workload
-     * TODO: maybe add a check if there is already an edge
-     */
-    @Override
-    public void addConsumerEdge(FlowEdge consumerEdge) {
-        this.workloadEdge = consumerEdge;
-    }
-
-    /**
-     * Add an edge to the cpuMux
-     * TODO: maybe add a check if there is already an edge
-     */
-    @Override
-    public void addSupplierEdge(FlowEdge supplierEdge) {
-        this.cpuEdge = supplierEdge;
-    }
-
-    /**
-     * Push demand to the cpuMux if the demand has changed
-     **/
-    @Override
-    public void pushOutgoingDemand(FlowEdge supplierEdge, double newDemand) {
-        this.cpuEdge.pushDemand(newDemand);
-    }
-
-    /**
-     * Push supply to the workload if the supply has changed
-     **/
-    @Override
-    public void pushOutgoingSupply(FlowEdge consumerEdge, double newSupply) {
-        this.workloadEdge.pushSupply(newSupply);
-    }
-
-    /**
-     * Handle new demand from the workload by sending it through to the cpuMux
-     **/
-    @Override
-    public void handleIncomingDemand(FlowEdge consumerEdge, double newDemand) {
-
-        updateCounters(this.clock.millis());
-        this.cpuDemand = newDemand;
-
-        pushOutgoingDemand(this.cpuEdge, newDemand);
-    }
-
-    /**
-     * Handle a new supply pushed by the cpuMux by sending it through to the workload
-     **/
-    @Override
-    public void handleIncomingSupply(FlowEdge supplierEdge, double newCpuSupply) {
-
-        updateCounters(this.clock.millis());
-        this.cpuSupply = newCpuSupply;
-
-        pushOutgoingSupply(this.workloadEdge, newCpuSupply);
-    }
-
-    @Override
-    public void removeConsumerEdge(FlowEdge consumerEdge) {
-        this.workloadEdge = null;
-        this.shutdown();
-    }
-
-    @Override
-    public double getCapacity() {
-        return this.cpuCapacity;
-    }
-
-    @Override
-    public void removeSupplierEdge(FlowEdge supplierEdge) {
-        this.cpuEdge = null;
-        this.shutdown();
-    }
-}
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/memory/Memory.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/memory/Memory.java
index d4406b20..2686cfa2 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/memory/Memory.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/memory/Memory.java
@@ -23,7 +23,7 @@
 package org.opendc.simulator.compute.memory;
 
 import org.opendc.simulator.compute.models.MemoryUnit;
-import org.opendc.simulator.engine.graph.FlowGraph;
+import org.opendc.simulator.engine.engine.FlowEngine;
 
 /**
  * The [SimMemory] implementation for a machine.
@@ -32,7 +32,7 @@ public final class Memory {
     //    private final SimpleFlowSink sink;
     private final MemoryUnit memoryUnit;
 
-    public Memory(FlowGraph graph, MemoryUnit memoryUnit) {
+    public Memory(FlowEngine engine, MemoryUnit memoryUnit) {
 
         this.memoryUnit = memoryUnit;
         // TODO: Fix this
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/CarbonModel.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/CarbonModel.java
index b6246fe9..3bbdba66 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/CarbonModel.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/CarbonModel.java
@@ -24,7 +24,9 @@ package org.opendc.simulator.compute.power;
 
 import java.util.ArrayList;
 import java.util.List;
-import org.opendc.simulator.engine.graph.FlowGraph;
+import java.util.Map;
+import org.opendc.simulator.engine.engine.FlowEngine;
+import org.opendc.simulator.engine.graph.FlowEdge;
 import org.opendc.simulator.engine.graph.FlowNode;
 
 /**
@@ -45,13 +47,13 @@ public class CarbonModel extends FlowNode {
     /**
      * Construct a CarbonModel
      *
-     * @param parentGraph The active FlowGraph which should be used to make the new FlowNode
+     * @param engine The {@link FlowEngine} the node belongs to
      * @param carbonFragments A list of Carbon Fragments defining the carbon intensity at different time frames
      * @param startTime The start time of the simulation. This is used to go from relative time (used by the clock)
      *                  to absolute time (used by carbon fragments).
      */
-    public CarbonModel(FlowGraph parentGraph, List<CarbonFragment> carbonFragments, long startTime) {
-        super(parentGraph);
+    public CarbonModel(FlowEngine engine, List<CarbonFragment> carbonFragments, long startTime) {
+        super(engine);
 
         this.startTime = startTime;
         this.fragments = carbonFragments;
@@ -66,6 +68,8 @@ public class CarbonModel extends FlowNode {
             receiver.removeCarbonModel(this);
         }
 
+        receivers.clear();
+
         this.closeNode();
     }
 
@@ -128,4 +132,17 @@ public class CarbonModel extends FlowNode {
 
         receiver.updateCarbonIntensity(this.current_fragment.getCarbonIntensity());
     }
+
+    public static <T, U> List<U> castList(List<T> list, Class<U> clazz) {
+        List<U> result = new ArrayList<>();
+        for (T element : list) {
+            result.add(clazz.cast(element));
+        }
+        return result;
+    }
+
+    @Override
+    public Map<FlowEdge.NodeType, List<FlowEdge>> getConnectedEdges() {
+        return Map.of();
+    }
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/SimPowerSource.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/SimPowerSource.java
index 718bc22a..34804230 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/SimPowerSource.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/SimPowerSource.java
@@ -22,9 +22,11 @@
 
 package org.opendc.simulator.compute.power;
 
+import java.util.List;
+import java.util.Map;
 import org.opendc.simulator.compute.cpu.SimCpu;
+import org.opendc.simulator.engine.engine.FlowEngine;
 import org.opendc.simulator.engine.graph.FlowEdge;
-import org.opendc.simulator.engine.graph.FlowGraph;
 import org.opendc.simulator.engine.graph.FlowNode;
 import org.opendc.simulator.engine.graph.FlowSupplier;
 
@@ -111,8 +113,8 @@ public final class SimPowerSource extends FlowNode implements FlowSupplier, Carb
     // Constructors
     ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
-    public SimPowerSource(FlowGraph graph, double max_capacity, String name, String clusterName) {
-        super(graph);
+    public SimPowerSource(FlowEngine engine, double max_capacity, String name, String clusterName) {
+        super(engine);
 
         this.capacity = max_capacity;
 
@@ -208,4 +210,11 @@ public final class SimPowerSource extends FlowNode implements FlowSupplier, Carb
     public void removeCarbonModel(CarbonModel carbonModel) {
         this.carbonModel = null;
     }
+
+    @Override
+    public Map<FlowEdge.NodeType, List<FlowEdge>> getConnectedEdges() {
+        List<FlowEdge> supplierEdges = this.distributorEdge != null ? List.of(this.distributorEdge) : List.of();
+
+        return Map.of(FlowEdge.NodeType.SUPPLYING, supplierEdges);
+    }
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/SimPsu.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/SimPsu.java
index dc5129d6..87a4e791 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/SimPsu.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/SimPsu.java
@@ -22,10 +22,12 @@
 
 package org.opendc.simulator.compute.power;
 
+import java.util.List;
+import java.util.Map;
 import org.opendc.simulator.compute.cpu.SimCpu;
+import org.opendc.simulator.engine.engine.FlowEngine;
 import org.opendc.simulator.engine.graph.FlowConsumer;
 import org.opendc.simulator.engine.graph.FlowEdge;
-import org.opendc.simulator.engine.graph.FlowGraph;
 import org.opendc.simulator.engine.graph.FlowNode;
 import org.opendc.simulator.engine.graph.FlowSupplier;
 
@@ -90,8 +92,8 @@ public final class SimPsu extends FlowNode implements FlowSupplier, FlowConsumer
     // Constructors
     ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
-    public SimPsu(FlowGraph graph) {
-        super(graph);
+    public SimPsu(FlowEngine engine) {
+        super(engine);
 
         lastUpdate = this.clock.millis();
     }
@@ -183,4 +185,14 @@ public final class SimPsu extends FlowNode implements FlowSupplier, FlowConsumer
     public void removeSupplierEdge(FlowEdge supplierEdge) {
         this.powerSupplyEdge = null;
     }
+
+    @Override
+    public Map<FlowEdge.NodeType, List<FlowEdge>> getConnectedEdges() {
+        List<FlowEdge> supplyingEdges = cpuEdge != null ? List.of(cpuEdge) : List.of();
+        List<FlowEdge> consumingEdges = powerSupplyEdge != null ? List.of(powerSupplyEdge) : List.of();
+
+        return Map.of(
+                FlowEdge.NodeType.SUPPLYING, supplyingEdges,
+                FlowEdge.NodeType.CONSUMING, consumingEdges);
+    }
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/BatteryAggregator.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/BatteryAggregator.java
index 14d15b17..9a05f2b3 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/BatteryAggregator.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/BatteryAggregator.java
@@ -24,10 +24,12 @@ package org.opendc.simulator.compute.power.batteries;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import org.opendc.simulator.engine.engine.FlowEngine;
 import org.opendc.simulator.engine.graph.FlowConsumer;
 import org.opendc.simulator.engine.graph.FlowDistributor;
 import org.opendc.simulator.engine.graph.FlowEdge;
-import org.opendc.simulator.engine.graph.FlowGraph;
 import org.opendc.simulator.engine.graph.FlowNode;
 import org.opendc.simulator.engine.graph.FlowSupplier;
 
@@ -52,14 +54,15 @@ public class BatteryAggregator extends FlowNode implements FlowConsumer, FlowSup
     /**
      * Construct a new {@link FlowNode} instance.
      *
-     * @param parentGraph The {@link FlowGraph} this stage belongs to.
+     * @param engine The {@link FlowEngine} this node belongs to.
      */
-    public BatteryAggregator(FlowGraph parentGraph, SimBattery battery, FlowDistributor powerSourceDistributor) {
-        super(parentGraph);
+    public BatteryAggregator(FlowEngine engine, SimBattery battery, FlowDistributor powerSourceDistributor) {
+        super(engine);
 
-        this.powerSourceEdge = parentGraph.addEdge(this, powerSourceDistributor);
+        this.powerSourceEdge = new FlowEdge(this, powerSourceDistributor);
         this.powerSourceEdge.setSupplierIndex(0);
-        this.batteryEdge = parentGraph.addEdge(this, battery);
+
+        this.batteryEdge = new FlowEdge(this, battery);
         this.batteryEdge.setSupplierIndex(1);
     }
 
@@ -170,4 +173,21 @@ public class BatteryAggregator extends FlowNode implements FlowConsumer, FlowSup
     public double getCapacity() {
         return 0;
     }
+
+    @Override
+    public Map<FlowEdge.NodeType, List<FlowEdge>> getConnectedEdges() {
+        List<FlowEdge> consumingEdges = new ArrayList<>();
+        if (this.powerSourceEdge != null) {
+            consumingEdges.add(this.batteryEdge);
+        }
+        if (this.batteryEdge != null) {
+            consumingEdges.add(this.powerSourceEdge);
+        }
+
+        List<FlowEdge> supplyingEdges = this.hostEdge != null ? List.of(this.hostEdge) : List.of();
+
+        return Map.of(
+                FlowEdge.NodeType.CONSUMING, consumingEdges,
+                FlowEdge.NodeType.SUPPLYING, supplyingEdges);
+    }
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/SimBattery.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/SimBattery.java
index f09cbcee..d749af72 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/SimBattery.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/SimBattery.java
@@ -22,10 +22,12 @@
 
 package org.opendc.simulator.compute.power.batteries;
 
+import java.util.List;
+import java.util.Map;
 import org.opendc.simulator.compute.power.batteries.policy.BatteryPolicy;
+import org.opendc.simulator.engine.engine.FlowEngine;
 import org.opendc.simulator.engine.graph.FlowConsumer;
 import org.opendc.simulator.engine.graph.FlowEdge;
-import org.opendc.simulator.engine.graph.FlowGraph;
 import org.opendc.simulator.engine.graph.FlowNode;
 import org.opendc.simulator.engine.graph.FlowSupplier;
 
@@ -120,7 +122,7 @@ public class SimBattery extends FlowNode implements FlowConsumer, FlowSupplier {
     /**
      * Construct a new {@link SimBattery} instance.
      *
-     * @param parentGraph The {@link FlowGraph} instance this battery is part of.
+     * @param engine The {@link FlowEngine} instance this battery is part of.
      * @param capacity The capacity of the battery in kWh.
      * @param chargingSpeed The charging speed of the battery in J.
      * @param initialCharge The initial charge of the battery in kWh.
@@ -130,7 +132,7 @@ public class SimBattery extends FlowNode implements FlowConsumer, FlowSupplier {
      * @param expectedLifeTime The expected lifetime of the battery in years.
      */
     public SimBattery(
-            FlowGraph parentGraph,
+            FlowEngine engine,
             double capacity,
             double chargingSpeed,
             double initialCharge,
@@ -139,7 +141,7 @@ public class SimBattery extends FlowNode implements FlowConsumer, FlowSupplier {
             Double totalEmbodiedCarbon,
             Double expectedLifeTime) {
 
-        super(parentGraph);
+        super(engine);
         this.capacity = capacity * 3600000;
         this.chargingSpeed = chargingSpeed;
 
@@ -319,4 +321,14 @@ public class SimBattery extends FlowNode implements FlowConsumer, FlowSupplier {
     public void removeConsumerEdge(FlowEdge consumerEdge) {
         this.close();
     }
+
+    @Override
+    public Map<FlowEdge.NodeType, List<FlowEdge>> getConnectedEdges() {
+        List<FlowEdge> consumingEdges = (this.distributorEdge != null) ? List.of(this.distributorEdge) : List.of();
+        List<FlowEdge> supplyingEdges = (this.aggregatorEdge != null) ? List.of(this.aggregatorEdge) : List.of();
+
+        return Map.of(
+                FlowEdge.NodeType.CONSUMING, consumingEdges,
+                FlowEdge.NodeType.SUPPLYING, supplyingEdges);
+    }
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/BatteryPolicy.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/BatteryPolicy.java
index a50f7e73..9d983a67 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/BatteryPolicy.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/BatteryPolicy.java
@@ -22,13 +22,16 @@
 
 package org.opendc.simulator.compute.power.batteries.policy;
 
+import java.util.List;
+import java.util.Map;
 import org.opendc.simulator.compute.power.CarbonModel;
 import org.opendc.simulator.compute.power.CarbonReceiver;
 import org.opendc.simulator.compute.power.batteries.BatteryAggregator;
 import org.opendc.simulator.compute.power.batteries.BatteryState;
 import org.opendc.simulator.compute.power.batteries.PowerSourceType;
 import org.opendc.simulator.compute.power.batteries.SimBattery;
-import org.opendc.simulator.engine.graph.FlowGraph;
+import org.opendc.simulator.engine.engine.FlowEngine;
+import org.opendc.simulator.engine.graph.FlowEdge;
 import org.opendc.simulator.engine.graph.FlowNode;
 
 /**
@@ -47,10 +50,10 @@ public abstract class BatteryPolicy extends FlowNode implements CarbonReceiver {
     /**
      * Construct a new {@link FlowNode} instance.
      *
-     * @param parentGraph The {@link FlowGraph} this stage belongs to.
+     * @param engine The {@link FlowEngine} this node belongs to.
      */
-    public BatteryPolicy(FlowGraph parentGraph, SimBattery battery, BatteryAggregator aggregator) {
-        super(parentGraph);
+    public BatteryPolicy(FlowEngine engine, SimBattery battery, BatteryAggregator aggregator) {
+        super(engine);
 
         this.battery = battery;
         this.battery.setBatteryPolicy(this);
@@ -114,4 +117,9 @@ public abstract class BatteryPolicy extends FlowNode implements CarbonReceiver {
     public void removeCarbonModel(CarbonModel carbonModel) {
         this.close();
     }
+
+    @Override
+    public Map<FlowEdge.NodeType, List<FlowEdge>> getConnectedEdges() {
+        return Map.of(FlowEdge.NodeType.SUPPLYING, List.of());
+    }
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/DoubleThresholdBatteryPolicy.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/DoubleThresholdBatteryPolicy.java
index 3a9cb228..28302f4d 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/DoubleThresholdBatteryPolicy.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/DoubleThresholdBatteryPolicy.java
@@ -25,7 +25,7 @@ package org.opendc.simulator.compute.power.batteries.policy;
 import org.opendc.simulator.compute.power.batteries.BatteryAggregator;
 import org.opendc.simulator.compute.power.batteries.BatteryState;
 import org.opendc.simulator.compute.power.batteries.SimBattery;
-import org.opendc.simulator.engine.graph.FlowGraph;
+import org.opendc.simulator.engine.engine.FlowEngine;
 
 /**
  * A battery policy that uses two thresholds to determine if a better should be charging or discharging.
@@ -42,19 +42,19 @@ public class DoubleThresholdBatteryPolicy extends BatteryPolicy {
 
     /**
      *
-     * @param parentGraph     The {@link FlowGraph} this stage belongs to.
+     * @param engine     The {@link FlowEngine} this node belongs to.
      * @param battery        The {@link SimBattery} to control.
      * @param aggregator    The {@link BatteryAggregator} to use.
      * @param lowerThreshold The lower carbon intensity threshold to trigger charging or discharging.
      * @param upperThreshold The upper carbon intensity threshold to trigger charging or discharging.
      */
     public DoubleThresholdBatteryPolicy(
-            FlowGraph parentGraph,
+            FlowEngine engine,
             SimBattery battery,
             BatteryAggregator aggregator,
             double lowerThreshold,
             double upperThreshold) {
-        super(parentGraph, battery, aggregator);
+        super(engine, battery, aggregator);
 
         this.lowerThreshold = lowerThreshold;
         this.upperThreshold = upperThreshold;
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/RunningMeanBatteryPolicy.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/RunningMeanBatteryPolicy.java
index 1c127abd..63e03942 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/RunningMeanBatteryPolicy.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/RunningMeanBatteryPolicy.java
@@ -26,7 +26,7 @@ import java.util.LinkedList;
 import org.opendc.simulator.compute.power.batteries.BatteryAggregator;
 import org.opendc.simulator.compute.power.batteries.BatteryState;
 import org.opendc.simulator.compute.power.batteries.SimBattery;
-import org.opendc.simulator.engine.graph.FlowGraph;
+import org.opendc.simulator.engine.engine.FlowEngine;
 
 /**
  * A battery policy that uses a running mean to determine if a battery should be charging or discharging.
@@ -46,17 +46,17 @@ public class RunningMeanBatteryPolicy extends BatteryPolicy {
 
     /**
      *
-     * @param parentGraph     The {@link FlowGraph} this stage belongs to.
+     * @param engine     The {@link FlowEngine} this node belongs to.
      * @param battery        The {@link SimBattery} to control.
      * @param aggregator    The {@link BatteryAggregator} to use.
      */
     public RunningMeanBatteryPolicy(
-            FlowGraph parentGraph,
+            FlowEngine engine,
             SimBattery battery,
             BatteryAggregator aggregator,
             double startingThreshold,
             int windowSize) {
-        super(parentGraph, battery, aggregator);
+        super(engine, battery, aggregator);
 
         this.windowSize = windowSize;
 
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/RunningMeanPlusBatteryPolicy.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/RunningMeanPlusBatteryPolicy.java
index 25b86dde..3330cd4e 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/RunningMeanPlusBatteryPolicy.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/RunningMeanPlusBatteryPolicy.java
@@ -26,7 +26,7 @@ import java.util.LinkedList;
 import org.opendc.simulator.compute.power.batteries.BatteryAggregator;
 import org.opendc.simulator.compute.power.batteries.BatteryState;
 import org.opendc.simulator.compute.power.batteries.SimBattery;
-import org.opendc.simulator.engine.graph.FlowGraph;
+import org.opendc.simulator.engine.engine.FlowEngine;
 
 /**
  * An improved version of {@link RunningMeanBatteryPolicy}.
@@ -43,17 +43,17 @@ public class RunningMeanPlusBatteryPolicy extends BatteryPolicy {
 
     /**
      *
-     * @param parentGraph     The {@link FlowGraph} this stage belongs to.
+     * @param engine     The {@link FlowEngine} this stage belongs to.
      * @param battery        The {@link SimBattery} to control.
      * @param aggregator    The {@link BatteryAggregator} to use.
      */
     public RunningMeanPlusBatteryPolicy(
-            FlowGraph parentGraph,
+            FlowEngine engine,
             SimBattery battery,
             BatteryAggregator aggregator,
             double startingThreshold,
             int windowSize) {
-        super(parentGraph, battery, aggregator);
+        super(engine, battery, aggregator);
 
         this.windowSize = windowSize;
 
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/SingleThresholdBatteryPolicy.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/SingleThresholdBatteryPolicy.java
index 26d85958..22e6ae2f 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/SingleThresholdBatteryPolicy.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/power/batteries/policy/SingleThresholdBatteryPolicy.java
@@ -25,7 +25,7 @@ package org.opendc.simulator.compute.power.batteries.policy;
 import org.opendc.simulator.compute.power.batteries.BatteryAggregator;
 import org.opendc.simulator.compute.power.batteries.BatteryState;
 import org.opendc.simulator.compute.power.batteries.SimBattery;
-import org.opendc.simulator.engine.graph.FlowGraph;
+import org.opendc.simulator.engine.engine.FlowEngine;
 
 /**
  * A battery policy that uses a single threshold to determine if a better should be charging or discharging.
@@ -38,14 +38,14 @@ public class SingleThresholdBatteryPolicy extends BatteryPolicy {
     private final double carbonThreshold;
 
     /**
-     * @param parentGraph     The {@link FlowGraph} this stage belongs to.
+     * @param engine     The {@link FlowEngine} this node belongs to.
      * @param battery        The {@link SimBattery} to control.
      * @param aggregator    The {@link BatteryAggregator} to use.
      * @param carbonThreshold The carbon intensity threshold to trigger charging or discharging.
      */
     public SingleThresholdBatteryPolicy(
-            FlowGraph parentGraph, SimBattery battery, BatteryAggregator aggregator, double carbonThreshold) {
-        super(parentGraph, battery, aggregator);
+            FlowEngine engine, SimBattery battery, BatteryAggregator aggregator, double carbonThreshold) {
+        super(engine, battery, aggregator);
 
         this.carbonThreshold = carbonThreshold;
     }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/ChainWorkload.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/ChainWorkload.java
index ecd4c47f..76a715f7 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/ChainWorkload.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/ChainWorkload.java
@@ -23,6 +23,8 @@
 package org.opendc.simulator.compute.workload;
 
 import java.util.ArrayList;
+import java.util.function.Consumer;
+import org.opendc.simulator.compute.machine.SimMachine;
 import org.opendc.simulator.engine.graph.FlowSupplier;
 
 public class ChainWorkload implements Workload {
@@ -66,7 +68,12 @@ public class ChainWorkload implements Workload {
     }
 
     @Override
-    public SimWorkload startWorkload(FlowSupplier supplier, long now) {
-        return new SimChainWorkload(supplier, this, now);
+    public SimWorkload startWorkload(FlowSupplier supplier) {
+        return new SimChainWorkload(supplier, this);
+    }
+
+    @Override
+    public SimWorkload startWorkload(FlowSupplier supplier, SimMachine machine, Consumer<Exception> completion) {
+        return new SimChainWorkload(supplier, this, machine, completion);
     }
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/CheckpointModel.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/CheckpointModel.java
index 6cc67e3f..d34da203 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/CheckpointModel.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/CheckpointModel.java
@@ -27,9 +27,10 @@ package org.opendc.simulator.compute.workload;
 // TODO: Move this to a separate file
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
-import java.time.InstantSource;
+import java.util.List;
+import java.util.Map;
 import org.jetbrains.annotations.NotNull;
-import org.opendc.simulator.engine.graph.FlowGraph;
+import org.opendc.simulator.engine.graph.FlowEdge;
 import org.opendc.simulator.engine.graph.FlowNode;
 
 public class CheckpointModel extends FlowNode {
@@ -37,23 +38,18 @@ public class CheckpointModel extends FlowNode {
     private long checkpointInterval;
     private final long checkpointDuration;
     private double checkpointIntervalScaling;
-    private FlowGraph graph;
 
     private long startOfInterval;
 
     public CheckpointModel(@NotNull SimWorkload simWorkload) {
-        super(simWorkload.getGraph());
+        super(simWorkload.getEngine());
 
         this.checkpointInterval = simWorkload.getCheckpointInterval();
         this.checkpointDuration = simWorkload.getCheckpointDuration();
         this.checkpointIntervalScaling = simWorkload.getCheckpointIntervalScaling();
         this.simWorkload = simWorkload;
 
-        this.graph = simWorkload.getGraph();
-
-        InstantSource clock = graph.getEngine().getClock();
-
-        this.startOfInterval = clock.millis();
+        this.startOfInterval = this.clock.millis();
     }
 
     @Override
@@ -89,6 +85,10 @@ public class CheckpointModel extends FlowNode {
         this.closeNode();
 
         this.simWorkload = null;
-        this.graph = null;
+    }
+
+    @Override
+    public Map<FlowEdge.NodeType, List<FlowEdge>> getConnectedEdges() {
+        return Map.of();
     }
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/SimChainWorkload.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/SimChainWorkload.java
index da6b8334..faab5c56 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/SimChainWorkload.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/SimChainWorkload.java
@@ -23,6 +23,11 @@
 package org.opendc.simulator.compute.workload;
 
 import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Consumer;
+import org.opendc.simulator.compute.machine.PerformanceCounters;
+import org.opendc.simulator.compute.machine.SimMachine;
 import org.opendc.simulator.engine.graph.FlowEdge;
 import org.opendc.simulator.engine.graph.FlowNode;
 import org.opendc.simulator.engine.graph.FlowSupplier;
@@ -30,13 +35,15 @@ import org.opendc.simulator.engine.graph.FlowSupplier;
 /**
  * A {@link SimChainWorkload} that composes multiple {@link SimWorkload}s.
  */
-final class SimChainWorkload extends SimWorkload implements FlowSupplier {
+public final class SimChainWorkload extends SimWorkload implements FlowSupplier {
     private final LinkedList<Workload> workloads;
     private int workloadIndex;
 
     private SimWorkload activeWorkload;
-    private double demand = 0.0f;
-    private double supply = 0.0f;
+    private double cpuDemand = 0.0f;
+    private double cpuSupply = 0.0f;
+    private double cpuCapacity = 0.0f;
+    private double d = 0.0f;
 
     private FlowEdge workloadEdge;
     private FlowEdge machineEdge;
@@ -50,6 +57,10 @@ final class SimChainWorkload extends SimWorkload implements FlowSupplier {
 
     private ChainWorkload snapshot;
 
+    private long lastUpdate;
+    private PerformanceCounters performanceCounters = new PerformanceCounters();
+    private Consumer<Exception> completion;
+
     ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
     // Basic Getters and Setters
     ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -79,24 +90,28 @@ final class SimChainWorkload extends SimWorkload implements FlowSupplier {
         return checkpointIntervalScaling;
     }
 
+    public PerformanceCounters getPerformanceCounters() {
+        return performanceCounters;
+    }
+
     ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
     // Constructors
     ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
-    SimChainWorkload(FlowSupplier supplier, ChainWorkload workload, long now) {
-        super(((FlowNode) supplier).getGraph());
+    SimChainWorkload(FlowSupplier supplier, ChainWorkload workload) {
+        super(((FlowNode) supplier).getEngine());
 
         this.snapshot = workload;
 
-        this.parentGraph = ((FlowNode) supplier).getGraph();
-        this.parentGraph.addEdge(this, supplier);
+        new FlowEdge(this, supplier);
 
-        this.clock = this.parentGraph.getEngine().getClock();
         this.workloads = new LinkedList<>(workload.getWorkloads());
         this.checkpointInterval = workload.getCheckpointInterval();
         this.checkpointDuration = workload.getCheckpointDuration();
         this.checkpointIntervalScaling = workload.getCheckpointIntervalScaling();
 
+        this.lastUpdate = clock.millis();
+
         if (checkpointInterval > 0) {
             this.createCheckpointModel();
         }
@@ -106,6 +121,15 @@ final class SimChainWorkload extends SimWorkload implements FlowSupplier {
         this.onStart();
     }
 
+    SimChainWorkload(
+            FlowSupplier supplier, ChainWorkload workload, SimMachine machine, Consumer<Exception> completion) {
+        this(supplier, workload);
+
+        this.capacity = machine.getCpu().getFrequency();
+        this.d = 1 / machine.getCpu().getFrequency();
+        this.completion = completion;
+    }
+
     public Workload getNextWorkload() {
         this.workloadIndex++;
         return workloads.pop();
@@ -122,7 +146,25 @@ final class SimChainWorkload extends SimWorkload implements FlowSupplier {
             this.checkpointModel.start();
         }
 
-        this.activeWorkload = this.getNextWorkload().startWorkload(this, this.clock.millis());
+        this.activeWorkload = this.getNextWorkload().startWorkload(this);
+    }
+
+    public void updateCounters(long now) {
+        long lastUpdate = this.lastUpdate;
+        this.lastUpdate = now;
+        long delta = now - lastUpdate;
+
+        if (delta > 0) {
+            final double factor = this.d * delta;
+
+            this.performanceCounters.addCpuActiveTime(Math.round(this.cpuSupply * factor));
+            this.performanceCounters.setCpuIdleTime(Math.round((this.cpuCapacity - this.cpuSupply) * factor));
+            this.performanceCounters.addCpuStealTime(Math.round((this.cpuDemand - this.cpuSupply) * factor));
+        }
+
+        this.performanceCounters.setCpuDemand(this.cpuDemand);
+        this.performanceCounters.setCpuSupply(this.cpuSupply);
+        this.performanceCounters.setCpuCapacity(this.cpuCapacity);
     }
 
     @Override
@@ -132,6 +174,16 @@ final class SimChainWorkload extends SimWorkload implements FlowSupplier {
 
     @Override
     public void stopWorkload() {
+        this.stopWorkload(null);
+    }
+
+    private Exception stopWorkloadCause = null;
+
+    public void stopWorkload(Exception cause) {
+        if (cause != null) {
+            this.stopWorkloadCause = cause;
+        }
+
         if (this.checkpointModel != null) {
             this.checkpointModel.close();
             this.checkpointModel = null;
@@ -143,6 +195,11 @@ final class SimChainWorkload extends SimWorkload implements FlowSupplier {
         }
 
         this.closeNode();
+
+        if (this.completion != null) {
+            this.completion.accept(stopWorkloadCause);
+            this.completion = null;
+        }
     }
 
     ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -197,7 +254,7 @@ final class SimChainWorkload extends SimWorkload implements FlowSupplier {
     @Override
     public void pushOutgoingDemand(FlowEdge supplierEdge, double newDemand) {
 
-        this.demand = newDemand;
+        this.cpuDemand = newDemand;
         this.machineEdge.pushDemand(newDemand);
     }
 
@@ -210,7 +267,7 @@ final class SimChainWorkload extends SimWorkload implements FlowSupplier {
     @Override
     public void pushOutgoingSupply(FlowEdge consumerEdge, double newSupply) {
 
-        this.supply = newSupply;
+        this.cpuSupply = newSupply;
         this.workloadEdge.pushSupply(newSupply);
     }
 
@@ -222,6 +279,8 @@ final class SimChainWorkload extends SimWorkload implements FlowSupplier {
      */
     @Override
     public void handleIncomingDemand(FlowEdge consumerEdge, double newDemand) {
+        updateCounters(this.clock.millis());
+
         this.pushOutgoingDemand(this.machineEdge, newDemand);
     }
 
@@ -233,6 +292,8 @@ final class SimChainWorkload extends SimWorkload implements FlowSupplier {
      */
     @Override
     public void handleIncomingSupply(FlowEdge supplierEdge, double newSupply) {
+        updateCounters(this.clock.millis());
+
         this.pushOutgoingSupply(this.machineEdge, newSupply);
     }
 
@@ -255,7 +316,7 @@ final class SimChainWorkload extends SimWorkload implements FlowSupplier {
 
         // Start next workload
         if (!this.workloads.isEmpty()) {
-            this.activeWorkload = getNextWorkload().startWorkload(this, this.clock.millis());
+            this.activeWorkload = getNextWorkload().startWorkload(this);
             return;
         }
 
@@ -276,4 +337,14 @@ final class SimChainWorkload extends SimWorkload implements FlowSupplier {
 
         this.stopWorkload();
     }
+
+    @Override
+    public Map<FlowEdge.NodeType, List<FlowEdge>> getConnectedEdges() {
+        List<FlowEdge> consumerEdges = (this.machineEdge != null) ? List.of(this.machineEdge) : List.of();
+        List<FlowEdge> supplierEdges = (this.workloadEdge != null) ? List.of(this.workloadEdge) : List.of();
+
+        return Map.of(
+                FlowEdge.NodeType.CONSUMING, consumerEdges,
+                FlowEdge.NodeType.SUPPLYING, supplierEdges);
+    }
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/SimWorkload.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/SimWorkload.java
index ebfcc552..d27d90af 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/SimWorkload.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/SimWorkload.java
@@ -22,8 +22,8 @@
 
 package org.opendc.simulator.compute.workload;
 
+import org.opendc.simulator.engine.engine.FlowEngine;
 import org.opendc.simulator.engine.graph.FlowConsumer;
-import org.opendc.simulator.engine.graph.FlowGraph;
 import org.opendc.simulator.engine.graph.FlowNode;
 
 /**
@@ -37,10 +37,10 @@ public abstract class SimWorkload extends FlowNode implements FlowConsumer {
     /**
      * Construct a new {@link FlowNode} instance.
      *
-     * @param parentGraph The {@link FlowGraph} this stage belongs to.
+     * @param engine The {@link FlowEngine} this stage belongs to.
      */
-    public SimWorkload(FlowGraph parentGraph) {
-        super(parentGraph);
+    public SimWorkload(FlowEngine engine) {
+        super(engine);
     }
 
     /**
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/Workload.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/Workload.java
index d85669bb..1d069bae 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/Workload.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/Workload.java
@@ -22,6 +22,8 @@
 
 package org.opendc.simulator.compute.workload;
 
+import java.util.function.Consumer;
+import org.opendc.simulator.compute.machine.SimMachine;
 import org.opendc.simulator.engine.graph.FlowSupplier;
 
 public interface Workload {
@@ -32,5 +34,7 @@ public interface Workload {
 
     double getCheckpointIntervalScaling();
 
-    SimWorkload startWorkload(FlowSupplier supplier, long now);
+    SimWorkload startWorkload(FlowSupplier supplier);
+
+    SimWorkload startWorkload(FlowSupplier supplier, SimMachine machine, Consumer<Exception> completion);
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/trace/SimTraceWorkload.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/trace/SimTraceWorkload.java
index 46354d4c..9811f72d 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/trace/SimTraceWorkload.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/trace/SimTraceWorkload.java
@@ -23,12 +23,13 @@
 package org.opendc.simulator.compute.workload.trace;
 
 import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
 import org.opendc.simulator.compute.workload.SimWorkload;
 import org.opendc.simulator.compute.workload.trace.scaling.NoDelayScaling;
 import org.opendc.simulator.compute.workload.trace.scaling.ScalingPolicy;
 import org.opendc.simulator.engine.graph.FlowConsumer;
 import org.opendc.simulator.engine.graph.FlowEdge;
-import org.opendc.simulator.engine.graph.FlowGraph;
 import org.opendc.simulator.engine.graph.FlowNode;
 import org.opendc.simulator.engine.graph.FlowSupplier;
 
@@ -46,9 +47,9 @@ public class SimTraceWorkload extends SimWorkload implements FlowConsumer {
     private double newCpuFreqSupplied = 0.0; // The Cpu speed supplied
     private double remainingWork = 0.0; // The duration of the fragment at the demanded speed
 
-    private long checkpointDuration;
+    private final long checkpointDuration;
 
-    private TraceWorkload snapshot;
+    private final TraceWorkload snapshot;
 
     private ScalingPolicy scalingPolicy = new NoDelayScaling();
 
@@ -83,8 +84,8 @@ public class SimTraceWorkload extends SimWorkload implements FlowConsumer {
     // Constructors
     ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
-    public SimTraceWorkload(FlowSupplier supplier, TraceWorkload workload, long now) {
-        super(((FlowNode) supplier).getGraph());
+    public SimTraceWorkload(FlowSupplier supplier, TraceWorkload workload) {
+        super(((FlowNode) supplier).getEngine());
 
         this.snapshot = workload;
         this.checkpointDuration = workload.getCheckpointDuration();
@@ -92,8 +93,7 @@ public class SimTraceWorkload extends SimWorkload implements FlowConsumer {
         this.remainingFragments = new LinkedList<>(workload.getFragments());
         this.fragmentIndex = 0;
 
-        final FlowGraph graph = ((FlowNode) supplier).getGraph();
-        graph.addEdge(this, supplier);
+        new FlowEdge(this, supplier);
     }
 
     ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -289,4 +289,9 @@ public class SimTraceWorkload extends SimWorkload implements FlowConsumer {
 
         this.stopWorkload();
     }
+
+    @Override
+    public Map<FlowEdge.NodeType, List<FlowEdge>> getConnectedEdges() {
+        return Map.of(FlowEdge.NodeType.CONSUMING, (this.machineEdge != null) ? List.of(this.machineEdge) : List.of());
+    }
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/trace/TraceWorkload.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/trace/TraceWorkload.java
index 47292a7b..80687b88 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/trace/TraceWorkload.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/workload/trace/TraceWorkload.java
@@ -25,6 +25,8 @@ package org.opendc.simulator.compute.workload.trace;
 import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.List;
+import java.util.function.Consumer;
+import org.opendc.simulator.compute.machine.SimMachine;
 import org.opendc.simulator.compute.workload.SimWorkload;
 import org.opendc.simulator.compute.workload.Workload;
 import org.opendc.simulator.compute.workload.trace.scaling.NoDelayScaling;
@@ -111,8 +113,13 @@ public class TraceWorkload implements Workload {
     }
 
     @Override
-    public SimWorkload startWorkload(FlowSupplier supplier, long now) {
-        return new SimTraceWorkload(supplier, this, now);
+    public SimWorkload startWorkload(FlowSupplier supplier) {
+        return new SimTraceWorkload(supplier, this);
+    }
+
+    @Override
+    public SimWorkload startWorkload(FlowSupplier supplier, SimMachine machine, Consumer<Exception> completion) {
+        return this.startWorkload(supplier);
     }
 
     public static Builder builder() {