refactor(compute): Simplify constructor of SimHost

This change updates the constructor of SimHost to receive a
`SimBareMetalMachine` and `SimHypervisor` directly instead of
construction these objects itself. This ensures better testability and
also simplifies the constructor of this class, especially when future
changes to `SimBareMetalMachine` or `SimHypervisor` change their
constructors.

3 files changed, 32 insertions, 66 deletions

diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/SimHost.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/SimHost.kt
index 56b1c8d1..0fa91d52 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/SimHost.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/SimHost.kt
@@ -35,17 +35,11 @@ import org.opendc.compute.simulator.internal.Guest
 import org.opendc.compute.simulator.internal.GuestListener
 import org.opendc.simulator.compute.*
 import org.opendc.simulator.compute.kernel.SimHypervisor
-import org.opendc.simulator.compute.kernel.SimHypervisorProvider
-import org.opendc.simulator.compute.kernel.cpufreq.PerformanceScalingGovernor
-import org.opendc.simulator.compute.kernel.cpufreq.ScalingGovernor
 import org.opendc.simulator.compute.kernel.interference.VmInterferenceDomain
 import org.opendc.simulator.compute.model.MachineModel
 import org.opendc.simulator.compute.model.MemoryUnit
-import org.opendc.simulator.compute.power.ConstantPowerModel
-import org.opendc.simulator.compute.power.PowerDriver
-import org.opendc.simulator.compute.power.SimplePowerDriver
 import org.opendc.simulator.compute.workload.SimWorkload
-import org.opendc.simulator.flow.FlowEngine
+import java.time.Clock
 import java.time.Duration
 import java.time.Instant
 import java.util.*
@@ -57,40 +51,21 @@ import kotlin.coroutines.CoroutineContext
 public class SimHost(
     override val uid: UUID,
     override val name: String,
-    model: MachineModel,
     override val meta: Map<String, Any>,
     private val context: CoroutineContext,
-    engine: FlowEngine,
-    hypervisorProvider: SimHypervisorProvider,
-    random: SplittableRandom,
-    scalingGovernor: ScalingGovernor = PerformanceScalingGovernor(),
-    powerDriver: PowerDriver = SimplePowerDriver(ConstantPowerModel(0.0)),
+    private val clock: Clock,
+    private val machine: SimBareMetalMachine,
+    private val hypervisor: SimHypervisor,
     private val mapper: SimWorkloadMapper = SimMetaWorkloadMapper(),
     private val interferenceDomain: VmInterferenceDomain? = null,
     private val optimize: Boolean = false
 ) : Host, AutoCloseable {
     /**
-     * The clock instance used by the host.
-     */
-    private val clock = engine.clock
-
-    /**
      * The event listeners registered with this host.
      */
     private val listeners = mutableListOf<HostListener>()
 
     /**
-     * The machine to run on.
-     */
-    public val machine: SimBareMetalMachine = SimBareMetalMachine(engine, model.optimize(), powerDriver)
-
-    /**
-     * The hypervisor to run multiple workloads.
-     */
-    private val hypervisor: SimHypervisor = hypervisorProvider
-        .create(engine, random, scalingGovernor = scalingGovernor)
-
-    /**
      * The virtual machines running on the hypervisor.
      */
     private val guests = HashMap<Server, Guest>()
@@ -109,7 +84,11 @@ public class SimHost(
             field = value
         }
 
-    override val model: HostModel = HostModel(model.cpus.sumOf { it.frequency }, model.cpus.size, model.memory.sumOf { it.size })
+    override val model: HostModel = HostModel(
+        machine.model.cpus.sumOf { it.frequency },
+        machine.model.cpus.size,
+        machine.model.memory.sumOf { it.size }
+    )
 
     /**
      * The [GuestListener] that listens for guest events.
@@ -341,26 +320,8 @@ public class SimHost(
         val processingUnits = (0 until cpuCount).map { originalCpu.copy(id = it, node = processingNode, frequency = cpuCapacity) }
         val memoryUnits = listOf(MemoryUnit("Generic", "Generic", 3200.0, memorySize))
 
-        return MachineModel(processingUnits, memoryUnits).optimize()
-    }
-
-    /**
-     * Optimize the [MachineModel] for simulation.
-     */
-    private fun MachineModel.optimize(): MachineModel {
-        if (!optimize) {
-            return this
-        }
-
-        val originalCpu = cpus[0]
-        val freq = cpus.sumOf { it.frequency }
-        val processingNode = originalCpu.node.copy(coreCount = 1)
-        val processingUnits = listOf(originalCpu.copy(frequency = freq, node = processingNode))
-
-        val memorySize = memory.sumOf { it.size }
-        val memoryUnits = listOf(MemoryUnit("Generic", "Generic", 3200.0, memorySize))
-
-        return MachineModel(processingUnits, memoryUnits)
+        val model = MachineModel(processingUnits, memoryUnits)
+        return if (optimize) model.optimize() else model
     }
 
     private var _lastReport = clock.millis()
diff --git a/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt b/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt
index 0b2285e5..06500a06 100644
--- a/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt
+++ b/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt
@@ -30,11 +30,14 @@ import org.junit.jupiter.api.assertAll
 import org.opendc.compute.api.*
 import org.opendc.compute.service.driver.Host
 import org.opendc.compute.service.driver.HostListener
-import org.opendc.simulator.compute.kernel.SimFairShareHypervisorProvider
+import org.opendc.simulator.compute.SimBareMetalMachine
+import org.opendc.simulator.compute.kernel.SimFairShareHypervisor
 import org.opendc.simulator.compute.model.MachineModel
 import org.opendc.simulator.compute.model.MemoryUnit
 import org.opendc.simulator.compute.model.ProcessingNode
 import org.opendc.simulator.compute.model.ProcessingUnit
+import org.opendc.simulator.compute.power.ConstantPowerModel
+import org.opendc.simulator.compute.power.SimplePowerDriver
 import org.opendc.simulator.compute.workload.SimTrace
 import org.opendc.simulator.compute.workload.SimTraceFragment
 import org.opendc.simulator.compute.workload.SimTraceWorkload
@@ -67,16 +70,16 @@ internal class SimHostTest {
     fun testOvercommitted() = runBlockingSimulation {
         val duration = 5 * 60L
         val engine = FlowEngine(coroutineContext, clock)
-        val random = SplittableRandom(1)
+        val machine = SimBareMetalMachine(engine, machineModel, SimplePowerDriver(ConstantPowerModel(0.0)))
+        val hypervisor = SimFairShareHypervisor(engine, null, SplittableRandom(1))
         val host = SimHost(
             uid = UUID.randomUUID(),
             name = "test",
-            model = machineModel,
             meta = emptyMap(),
             coroutineContext,
-            engine,
-            SimFairShareHypervisorProvider(),
-            random,
+            clock,
+            machine,
+            hypervisor
         )
         val vmImageA = MockImage(
             UUID.randomUUID(),
@@ -151,16 +154,16 @@ internal class SimHostTest {
     fun testFailure() = runBlockingSimulation {
         val duration = 5 * 60L
         val engine = FlowEngine(coroutineContext, clock)
-        val random = SplittableRandom(1)
+        val machine = SimBareMetalMachine(engine, machineModel, SimplePowerDriver(ConstantPowerModel(0.0)))
+        val hypervisor = SimFairShareHypervisor(engine, null, SplittableRandom(1))
         val host = SimHost(
             uid = UUID.randomUUID(),
             name = "test",
-            model = machineModel,
             meta = emptyMap(),
             coroutineContext,
-            engine,
-            SimFairShareHypervisorProvider(),
-            random
+            clock,
+            machine,
+            hypervisor
         )
         val image = MockImage(
             UUID.randomUUID(),
diff --git a/opendc-compute/opendc-compute-workload/src/main/kotlin/org/opendc/compute/workload/ComputeServiceHelper.kt b/opendc-compute/opendc-compute-workload/src/main/kotlin/org/opendc/compute/workload/ComputeServiceHelper.kt
index 879ef072..92652329 100644
--- a/opendc-compute/opendc-compute-workload/src/main/kotlin/org/opendc/compute/workload/ComputeServiceHelper.kt
+++ b/opendc-compute/opendc-compute-workload/src/main/kotlin/org/opendc/compute/workload/ComputeServiceHelper.kt
@@ -31,6 +31,7 @@ import org.opendc.compute.service.ComputeService
 import org.opendc.compute.service.scheduler.ComputeScheduler
 import org.opendc.compute.simulator.SimHost
 import org.opendc.compute.workload.topology.HostSpec
+import org.opendc.simulator.compute.SimBareMetalMachine
 import org.opendc.simulator.compute.kernel.interference.VmInterferenceModel
 import org.opendc.simulator.compute.workload.SimTraceWorkload
 import org.opendc.simulator.flow.FlowEngine
@@ -167,16 +168,17 @@ public class ComputeServiceHelper(
      * @return The [SimHost] that has been constructed by the runner.
      */
     public fun registerHost(spec: HostSpec, optimize: Boolean = false): SimHost {
+        val machine = SimBareMetalMachine(engine, spec.model, spec.powerDriver)
+        val hypervisor = spec.hypervisor.create(engine, random)
+
         val host = SimHost(
             spec.uid,
             spec.name,
-            spec.model,
             spec.meta,
             context,
-            engine,
-            spec.hypervisor,
-            random,
-            powerDriver = spec.powerDriver,
+            clock,
+            machine,
+            hypervisor,
             interferenceDomain = interferenceModel?.newDomain(),
             optimize = optimize
         )