merge: Increase minimum Java version to 17 (#115)

This pull request increases the minimum version of Java required by OpenDC to 17.
This new version of Java introduces several new features compared to our old minimum 
version (11), which we attempt to apply in this conversion.

## Implementation Notes :hammer_and_pick:

* Increase minimum Java version to Java 17 
* Use RandomGenerator as randomness source 
* Add common dispatcher interface 
* Add compatibility with Kotlin coroutines
* Use InstantSource as time source
* Re-implement SimulationScheduler as Dispatcher 
* Replace use of CoroutineContext by Dispatcher 

## External Dependencies :four_leaf_clover:

* Java 17

## Breaking API Changes :warning:

* The use of `CoroutineContext` and `Clock` as parameters of classes has been replaced 
  by the `Dispatcher` interface.
* The use of `Clock` has been replaced by `InstantSource` which does not carry time
   zone info.
* The use of `Random` and `SplittableRandom` as parameter type has been replaced 
   by `RandomGenerator`

8 files changed, 76 insertions, 76 deletions

diff --git a/opendc-simulator/opendc-simulator-compute/src/jmh/kotlin/org/opendc/simulator/compute/SimMachineBenchmarks.kt b/opendc-simulator/opendc-simulator-compute/src/jmh/kotlin/org/opendc/simulator/compute/SimMachineBenchmarks.kt
index ec032070..eea46b95 100644
--- a/opendc-simulator/opendc-simulator-compute/src/jmh/kotlin/org/opendc/simulator/compute/SimMachineBenchmarks.kt
+++ b/opendc-simulator/opendc-simulator-compute/src/jmh/kotlin/org/opendc/simulator/compute/SimMachineBenchmarks.kt
@@ -74,7 +74,7 @@ class SimMachineBenchmarks {
     @Benchmark
     fun benchmarkBareMetal() {
         return runSimulation {
-            val engine = FlowEngine.create(coroutineContext, clock)
+            val engine = FlowEngine.create(dispatcher)
             val graph = engine.newGraph()
             val machine = SimBareMetalMachine.create(graph, machineModel)
             return@runSimulation machine.runWorkload(trace.createWorkload(0))
@@ -84,7 +84,7 @@ class SimMachineBenchmarks {
     @Benchmark
     fun benchmarkSpaceSharedHypervisor() {
         return runSimulation {
-            val engine = FlowEngine.create(coroutineContext, clock)
+            val engine = FlowEngine.create(dispatcher)
             val graph = engine.newGraph()
             val machine = SimBareMetalMachine.create(graph, machineModel)
             val hypervisor = SimHypervisor.create(FlowMultiplexerFactory.forwardingMultiplexer(), SplittableRandom(1))
@@ -105,7 +105,7 @@ class SimMachineBenchmarks {
     @Benchmark
     fun benchmarkFairShareHypervisorSingle() {
         return runSimulation {
-            val engine = FlowEngine.create(coroutineContext, clock)
+            val engine = FlowEngine.create(dispatcher)
             val graph = engine.newGraph()
             val machine = SimBareMetalMachine.create(graph, machineModel)
             val hypervisor = SimHypervisor.create(FlowMultiplexerFactory.maxMinMultiplexer(), SplittableRandom(1))
@@ -126,7 +126,7 @@ class SimMachineBenchmarks {
     @Benchmark
     fun benchmarkFairShareHypervisorDouble() {
         return runSimulation {
-            val engine = FlowEngine.create(coroutineContext, clock)
+            val engine = FlowEngine.create(dispatcher)
             val graph = engine.newGraph()
             val machine = SimBareMetalMachine.create(graph, machineModel)
             val hypervisor = SimHypervisor.create(FlowMultiplexerFactory.maxMinMultiplexer(), SplittableRandom(1))
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/SimPsuFactories.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/SimPsuFactories.java
index 52d04052..05b40cf8 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/SimPsuFactories.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/SimPsuFactories.java
@@ -22,7 +22,7 @@
 
 package org.opendc.simulator.compute;
 
-import java.time.Clock;
+import java.time.InstantSource;
 import org.jetbrains.annotations.NotNull;
 import org.opendc.simulator.compute.model.ProcessingUnit;
 import org.opendc.simulator.compute.power.CpuPowerModel;
@@ -117,7 +117,7 @@ public class SimPsuFactories {
         private final FlowStage stage;
         private final OutPort out;
         private final CpuPowerModel model;
-        private final Clock clock;
+        private final InstantSource clock;
 
         private double targetFreq;
         private double totalUsage;
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/kernel/SimHypervisor.java b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/kernel/SimHypervisor.java
index 4ebcba71..a1623351 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/kernel/SimHypervisor.java
+++ b/opendc-simulator/opendc-simulator-compute/src/main/java/org/opendc/simulator/compute/kernel/SimHypervisor.java
@@ -22,7 +22,7 @@
 
 package org.opendc.simulator.compute.kernel;
 
-import java.time.Clock;
+import java.time.InstantSource;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -253,7 +253,7 @@ public final class SimHypervisor implements SimWorkload {
         private final FlowMultiplexer multiplexer;
         private final FlowStage stage;
         private final List<ScalingGovernor> scalingGovernors;
-        private final Clock clock;
+        private final InstantSource clock;
         private final HvCounters counters;
 
         private long lastCounterUpdate;
@@ -526,7 +526,7 @@ public final class SimHypervisor implements SimWorkload {
         private final VmInterferenceMember interferenceMember;
         private final FlowStage stage;
         private final FlowMultiplexer multiplexer;
-        private final Clock clock;
+        private final InstantSource clock;
 
         private final List<VCpu> cpus;
         private final SimAbstractMachine.Memory memory;
diff --git a/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/SimMachineTest.kt b/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/SimMachineTest.kt
index 2acf6ec7..58b01e06 100644
--- a/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/SimMachineTest.kt
+++ b/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/SimMachineTest.kt
@@ -72,7 +72,7 @@ class SimMachineTest {
 
     @Test
     fun testFlopsWorkload() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -83,7 +83,7 @@ class SimMachineTest {
         machine.runWorkload(SimWorkloads.flops(2_000, /*utilization*/ 1.0))
 
         // Two cores execute 1000 MFlOps per second (1000 ms)
-        assertEquals(1000, clock.millis())
+        assertEquals(1000, timeSource.millis())
     }
 
     @Test
@@ -97,7 +97,7 @@ class SimMachineTest {
         }
         val trace = builder.build()
 
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
         val machine = SimBareMetalMachine.create(
             graph,
@@ -107,12 +107,12 @@ class SimMachineTest {
         machine.runWorkload(trace.createWorkload(0))
 
         // Two cores execute 1000 MFlOps per second (1000 ms)
-        assertEquals(1000000000, clock.millis())
+        assertEquals(1000000000, timeSource.millis())
     }
 
     @Test
     fun testDualSocketMachine() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val cpuNode = machineModel.cpus[0].node
@@ -128,12 +128,12 @@ class SimMachineTest {
         machine.runWorkload(SimWorkloads.flops(2_000, /*utilization*/ 1.0))
 
         // Two sockets with two cores execute 2000 MFlOps per second (500 ms)
-        assertEquals(500, clock.millis())
+        assertEquals(500, timeSource.millis())
     }
 
     @Test
     fun testPower() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
         val machine = SimBareMetalMachine.create(
             graph,
@@ -156,7 +156,7 @@ class SimMachineTest {
 
     @Test
     fun testCapacityClamp() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -184,7 +184,7 @@ class SimMachineTest {
 
     @Test
     fun testMemory() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -206,7 +206,7 @@ class SimMachineTest {
 
     @Test
     fun testMemoryUsage() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -225,12 +225,12 @@ class SimMachineTest {
             override fun snapshot(): SimWorkload = TODO()
         })
 
-        assertEquals(1000, clock.millis())
+        assertEquals(1000, timeSource.millis())
     }
 
     @Test
     fun testNetUsage() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -253,12 +253,12 @@ class SimMachineTest {
             override fun snapshot(): SimWorkload = TODO()
         })
 
-        assertEquals(40, clock.millis())
+        assertEquals(40, timeSource.millis())
     }
 
     @Test
     fun testDiskReadUsage() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -278,12 +278,12 @@ class SimMachineTest {
             override fun snapshot(): SimWorkload = TODO()
         })
 
-        assertEquals(4000, clock.millis())
+        assertEquals(4000, timeSource.millis())
     }
 
     @Test
     fun testDiskWriteUsage() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -303,12 +303,12 @@ class SimMachineTest {
             override fun snapshot(): SimWorkload = TODO()
         })
 
-        assertEquals(4000, clock.millis())
+        assertEquals(4000, timeSource.millis())
     }
 
     @Test
     fun testCancellation() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -325,12 +325,12 @@ class SimMachineTest {
             // Ignore
         }
 
-        assertEquals(0, clock.millis())
+        assertEquals(0, timeSource.millis())
     }
 
     @Test
     fun testConcurrentRuns() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -351,7 +351,7 @@ class SimMachineTest {
 
     @Test
     fun testCatchStartFailure() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -367,7 +367,7 @@ class SimMachineTest {
 
     @Test
     fun testCatchStopFailure() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -384,7 +384,7 @@ class SimMachineTest {
 
     @Test
     fun testCatchShutdownFailure() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -400,7 +400,7 @@ class SimMachineTest {
 
     @Test
     fun testCatchNestedFailure() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
diff --git a/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/kernel/SimFairShareHypervisorTest.kt b/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/kernel/SimFairShareHypervisorTest.kt
index 79669d40..99f47b2f 100644
--- a/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/kernel/SimFairShareHypervisorTest.kt
+++ b/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/kernel/SimFairShareHypervisorTest.kt
@@ -74,7 +74,7 @@ internal class SimFairShareHypervisorTest {
                 SimTraceFragment(duration * 3000, duration * 1000, 183.0, 1)
             ).createWorkload(0)
 
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(graph, model)
@@ -93,7 +93,7 @@ internal class SimFairShareHypervisorTest {
             { assertEquals(319781, hypervisor.counters.cpuActiveTime, "Active time does not match") },
             { assertEquals(880219, hypervisor.counters.cpuIdleTime, "Idle time does not match") },
             { assertEquals(28125, hypervisor.counters.cpuStealTime, "Steal time does not match") },
-            { assertEquals(1200000, clock.millis()) { "Current time is correct" } }
+            { assertEquals(1200000, timeSource.millis()) { "Current time is correct" } }
         )
     }
 
@@ -118,7 +118,7 @@ internal class SimFairShareHypervisorTest {
                 SimTraceFragment(duration * 3000, duration * 1000, 73.0, 1)
             ).createWorkload(0)
 
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(graph, model)
@@ -145,7 +145,7 @@ internal class SimFairShareHypervisorTest {
             { assertEquals(329250, hypervisor.counters.cpuActiveTime, "Active time does not match") },
             { assertEquals(870750, hypervisor.counters.cpuIdleTime, "Idle time does not match") },
             { assertEquals(318750, hypervisor.counters.cpuStealTime, "Steal time does not match") },
-            { assertEquals(1200000, clock.millis()) }
+            { assertEquals(1200000, timeSource.millis()) }
         )
     }
 
@@ -157,7 +157,7 @@ internal class SimFairShareHypervisorTest {
             /*memory*/ List(4) { MemoryUnit("Crucial", "MTA18ASF4G72AZ-3G2B1", 3200.0, 32_000) }
         )
 
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(graph, model)
@@ -184,7 +184,7 @@ internal class SimFairShareHypervisorTest {
             .addGroup(setOf("a", "n"), 0.1, 0.8)
             .build()
 
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(graph, model)
diff --git a/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/kernel/SimSpaceSharedHypervisorTest.kt b/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/kernel/SimSpaceSharedHypervisorTest.kt
index d11b91ee..93b67aa3 100644
--- a/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/kernel/SimSpaceSharedHypervisorTest.kt
+++ b/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/kernel/SimSpaceSharedHypervisorTest.kt
@@ -75,7 +75,7 @@ internal class SimSpaceSharedHypervisorTest {
                 SimTraceFragment(duration * 3000, duration * 1000, 183.0, 1)
             ).createWorkload(0)
 
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(graph, machineModel)
@@ -89,7 +89,7 @@ internal class SimSpaceSharedHypervisorTest {
         hypervisor.removeMachine(vm)
         machine.cancel()
 
-        assertEquals(5 * 60L * 4000, clock.millis()) { "Took enough time" }
+        assertEquals(5 * 60L * 4000, timeSource.millis()) { "Took enough time" }
     }
 
     /**
@@ -99,7 +99,7 @@ internal class SimSpaceSharedHypervisorTest {
     fun testRuntimeWorkload() = runSimulation {
         val duration = 5 * 60L * 1000
         val workload = SimWorkloads.runtime(duration, 1.0)
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(graph, machineModel)
@@ -113,7 +113,7 @@ internal class SimSpaceSharedHypervisorTest {
 
         machine.cancel()
 
-        assertEquals(duration, clock.millis()) { "Took enough time" }
+        assertEquals(duration, timeSource.millis()) { "Took enough time" }
     }
 
     /**
@@ -123,7 +123,7 @@ internal class SimSpaceSharedHypervisorTest {
     fun testFlopsWorkload() = runSimulation {
         val duration = 5 * 60L * 1000
         val workload = SimWorkloads.flops((duration * 3.2).toLong(), 1.0)
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(graph, machineModel)
@@ -135,7 +135,7 @@ internal class SimSpaceSharedHypervisorTest {
         vm.runWorkload(workload)
         machine.cancel()
 
-        assertEquals(duration, clock.millis()) { "Took enough time" }
+        assertEquals(duration, timeSource.millis()) { "Took enough time" }
     }
 
     /**
@@ -144,7 +144,7 @@ internal class SimSpaceSharedHypervisorTest {
     @Test
     fun testTwoWorkloads() = runSimulation {
         val duration = 5 * 60L * 1000
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(graph, machineModel)
@@ -165,7 +165,7 @@ internal class SimSpaceSharedHypervisorTest {
 
         machine.cancel()
 
-        assertEquals(duration * 2, clock.millis()) { "Took enough time" }
+        assertEquals(duration * 2, timeSource.millis()) { "Took enough time" }
     }
 
     /**
@@ -173,7 +173,7 @@ internal class SimSpaceSharedHypervisorTest {
      */
     @Test
     fun testConcurrentWorkloadFails() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(graph, machineModel)
@@ -200,7 +200,7 @@ internal class SimSpaceSharedHypervisorTest {
      */
     @Test
     fun testConcurrentWorkloadSucceeds() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(graph, machineModel)
diff --git a/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/workload/SimChainWorkloadTest.kt b/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/workload/SimChainWorkloadTest.kt
index d0b0efaa..08bb6509 100644
--- a/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/workload/SimChainWorkloadTest.kt
+++ b/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/workload/SimChainWorkloadTest.kt
@@ -59,7 +59,7 @@ class SimChainWorkloadTest {
 
     @Test
     fun testMultipleWorkloads() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -75,12 +75,12 @@ class SimChainWorkloadTest {
 
         machine.runWorkload(workload)
 
-        assertEquals(2000, clock.millis())
+        assertEquals(2000, timeSource.millis())
     }
 
     @Test
     fun testStartFailure() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -100,12 +100,12 @@ class SimChainWorkloadTest {
 
         assertThrows<IllegalStateException> { machine.runWorkload(workload) }
 
-        assertEquals(0, clock.millis())
+        assertEquals(0, timeSource.millis())
     }
 
     @Test
     fun testStartFailureSecond() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -126,12 +126,12 @@ class SimChainWorkloadTest {
 
         assertThrows<IllegalStateException> { machine.runWorkload(workload) }
 
-        assertEquals(1000, clock.millis())
+        assertEquals(1000, timeSource.millis())
     }
 
     @Test
     fun testStopFailure() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -150,12 +150,12 @@ class SimChainWorkloadTest {
 
         assertThrows<IllegalStateException> { machine.runWorkload(workload) }
 
-        assertEquals(1000, clock.millis())
+        assertEquals(1000, timeSource.millis())
     }
 
     @Test
     fun testStopFailureSecond() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -175,12 +175,12 @@ class SimChainWorkloadTest {
 
         assertThrows<IllegalStateException> { machine.runWorkload(workload) }
 
-        assertEquals(2000, clock.millis())
+        assertEquals(2000, timeSource.millis())
     }
 
     @Test
     fun testStartAndStopFailure() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -201,12 +201,12 @@ class SimChainWorkloadTest {
         val exc = assertThrows<IllegalStateException> { machine.runWorkload(workload) }
 
         assertEquals(2, exc.cause!!.suppressedExceptions.size)
-        assertEquals(1000, clock.millis())
+        assertEquals(1000, timeSource.millis())
     }
 
     @Test
     fun testShutdownAndStopFailure() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -227,12 +227,12 @@ class SimChainWorkloadTest {
         val exc = assertThrows<IllegalStateException> { machine.runWorkload(workload) }
 
         assertEquals(1, exc.cause!!.suppressedExceptions.size)
-        assertEquals(1000, clock.millis())
+        assertEquals(1000, timeSource.millis())
     }
 
     @Test
     fun testShutdownAndStartFailure() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -255,12 +255,12 @@ class SimChainWorkloadTest {
 
         val exc = assertThrows<IllegalStateException> { machine.runWorkload(workload) }
         assertEquals(1, exc.cause!!.suppressedExceptions.size)
-        assertEquals(1000, clock.millis())
+        assertEquals(1000, timeSource.millis())
     }
 
     @Test
     fun testSnapshot() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(graph, machineModel)
@@ -276,10 +276,10 @@ class SimChainWorkloadTest {
 
         job.join()
 
-        assertEquals(2000, clock.millis())
+        assertEquals(2000, timeSource.millis())
 
         machine.runWorkload(snapshot)
 
-        assertEquals(3500, clock.millis())
+        assertEquals(3500, timeSource.millis())
     }
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/workload/SimTraceWorkloadTest.kt b/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/workload/SimTraceWorkloadTest.kt
index e3b6e6c5..5c888fbc 100644
--- a/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/workload/SimTraceWorkloadTest.kt
+++ b/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/workload/SimTraceWorkloadTest.kt
@@ -53,7 +53,7 @@ class SimTraceWorkloadTest {
 
     @Test
     fun testSmoke() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -71,12 +71,12 @@ class SimTraceWorkloadTest {
 
         machine.runWorkload(workload)
 
-        assertEquals(4000, clock.millis())
+        assertEquals(4000, timeSource.millis())
     }
 
     @Test
     fun testOffset() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -94,12 +94,12 @@ class SimTraceWorkloadTest {
 
         machine.runWorkload(workload)
 
-        assertEquals(5000, clock.millis())
+        assertEquals(5000, timeSource.millis())
     }
 
     @Test
     fun testSkipFragment() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -118,12 +118,12 @@ class SimTraceWorkloadTest {
         delay(1000L)
         machine.runWorkload(workload)
 
-        assertEquals(4000, clock.millis())
+        assertEquals(4000, timeSource.millis())
     }
 
     @Test
     fun testZeroCores() = runSimulation {
-        val engine = FlowEngine.create(coroutineContext, clock)
+        val engine = FlowEngine.create(dispatcher)
         val graph = engine.newGraph()
 
         val machine = SimBareMetalMachine.create(
@@ -141,6 +141,6 @@ class SimTraceWorkloadTest {
 
         machine.runWorkload(workload)
 
-        assertEquals(4000, clock.millis())
+        assertEquals(4000, timeSource.millis())
     }
 }