simulator: Add support for central resource scheduling (#126)

This pull request adds support for central resource scheduling. 
This enables possible optimizations in the future where we can efficiently 
schedule resource updates.

* Introduce `SimResourceScheduler` which centralizes the logic for 
  scheduling resource interrupts.
* Fix benchmarks
* Add generic approach for reporting resource events
* Simplify scheduling logic of resource aggregator.

**Breaking API Changes**

* Classes in `opendc-simulator-resources` now take `SimResourceScheduler` as 
   opposed to a `CoroutineContext` and `Clock`.

8 files changed, 48 insertions, 70 deletions

diff --git a/opendc-simulator/opendc-simulator-compute/src/jmh/kotlin/org/opendc/simulator/compute/BenchmarkHelpers.kt b/opendc-simulator/opendc-simulator-compute/src/jmh/kotlin/org/opendc/simulator/compute/BenchmarkHelpers.kt
deleted file mode 100644
index 43bbfd0b..00000000
--- a/opendc-simulator/opendc-simulator-compute/src/jmh/kotlin/org/opendc/simulator/compute/BenchmarkHelpers.kt
+++ /dev/null
@@ -1,43 +0,0 @@
-/*
- * Copyright (c) 2021 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
-
-import org.opendc.simulator.compute.workload.SimTraceWorkload
-
-/**
- * Helper function to create simple consumer workload.
- */
-fun createSimpleConsumer(): SimTraceWorkload {
-    return SimTraceWorkload(
-        sequenceOf(
-            SimTraceWorkload.Fragment(1000, 28.0, 1),
-            SimTraceWorkload.Fragment(1000, 3500.0, 1),
-            SimTraceWorkload.Fragment(1000, 0.0, 1),
-            SimTraceWorkload.Fragment(1000, 183.0, 1),
-            SimTraceWorkload.Fragment(1000, 400.0, 1),
-            SimTraceWorkload.Fragment(1000, 100.0, 1),
-            SimTraceWorkload.Fragment(1000, 3000.0, 1),
-            SimTraceWorkload.Fragment(1000, 4500.0, 1),
-        ),
-    )
-}
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 7b97a665..15714aca 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
@@ -31,12 +31,12 @@ 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.workload.SimWorkload
+import org.opendc.simulator.compute.workload.SimTraceWorkload
 import org.opendc.simulator.core.SimulationCoroutineScope
 import org.opendc.simulator.core.runBlockingSimulation
-import org.opendc.utils.TimerScheduler
+import org.opendc.simulator.resources.SimResourceScheduler
+import org.opendc.simulator.resources.SimResourceSchedulerTrampoline
 import org.openjdk.jmh.annotations.*
-import java.time.Clock
 import java.util.concurrent.TimeUnit
 
 @State(Scope.Thread)
@@ -46,14 +46,13 @@ import java.util.concurrent.TimeUnit
 @OptIn(ExperimentalCoroutinesApi::class)
 class SimMachineBenchmarks {
     private lateinit var scope: SimulationCoroutineScope
-    private lateinit var clock: Clock
-    private lateinit var scheduler: TimerScheduler<Any>
+    private lateinit var scheduler: SimResourceScheduler
     private lateinit var machineModel: SimMachineModel
 
     @Setup
     fun setUp() {
         scope = SimulationCoroutineScope()
-        scheduler = TimerScheduler(scope.coroutineContext, clock)
+        scheduler = SimResourceSchedulerTrampoline(scope.coroutineContext, scope.clock)
 
         val cpuNode = ProcessingNode("Intel", "Xeon", "amd64", 2)
 
@@ -63,13 +62,22 @@ class SimMachineBenchmarks {
         )
     }
 
-    @State(Scope.Thread)
+    @State(Scope.Benchmark)
     class Workload {
-        lateinit var workloads: Array<SimWorkload>
+        lateinit var trace: Sequence<SimTraceWorkload.Fragment>
 
         @Setup
         fun setUp() {
-            workloads = Array(2) { createSimpleConsumer() }
+            trace = sequenceOf(
+                SimTraceWorkload.Fragment(1000, 28.0, 1),
+                SimTraceWorkload.Fragment(1000, 3500.0, 1),
+                SimTraceWorkload.Fragment(1000, 0.0, 1),
+                SimTraceWorkload.Fragment(1000, 183.0, 1),
+                SimTraceWorkload.Fragment(1000, 400.0, 1),
+                SimTraceWorkload.Fragment(1000, 100.0, 1),
+                SimTraceWorkload.Fragment(1000, 3000.0, 1),
+                SimTraceWorkload.Fragment(1000, 4500.0, 1),
+            )
         }
     }
 
@@ -80,7 +88,7 @@ class SimMachineBenchmarks {
                 coroutineContext, clock, machineModel, PerformanceScalingGovernor(),
                 SimpleScalingDriver(ConstantPowerModel(0.0))
             )
-            return@runBlockingSimulation machine.run(state.workloads[0])
+            return@runBlockingSimulation machine.run(SimTraceWorkload(state.trace))
         }
     }
 
@@ -98,7 +106,7 @@ class SimMachineBenchmarks {
             val vm = hypervisor.createMachine(machineModel)
 
             try {
-                return@runBlockingSimulation vm.run(state.workloads[0])
+                return@runBlockingSimulation vm.run(SimTraceWorkload(state.trace))
             } finally {
                 vm.close()
                 machine.close()
@@ -113,14 +121,14 @@ class SimMachineBenchmarks {
                 coroutineContext, clock, machineModel, PerformanceScalingGovernor(),
                 SimpleScalingDriver(ConstantPowerModel(0.0))
             )
-            val hypervisor = SimFairShareHypervisor()
+            val hypervisor = SimFairShareHypervisor(scheduler)
 
             launch { machine.run(hypervisor) }
 
             val vm = hypervisor.createMachine(machineModel)
 
             try {
-                return@runBlockingSimulation vm.run(state.workloads[0])
+                return@runBlockingSimulation vm.run(SimTraceWorkload(state.trace))
             } finally {
                 vm.close()
                 machine.close()
@@ -135,17 +143,17 @@ class SimMachineBenchmarks {
                 coroutineContext, clock, machineModel, PerformanceScalingGovernor(),
                 SimpleScalingDriver(ConstantPowerModel(0.0))
             )
-            val hypervisor = SimFairShareHypervisor()
+            val hypervisor = SimFairShareHypervisor(scheduler)
 
             launch { machine.run(hypervisor) }
 
             coroutineScope {
-                repeat(2) { i ->
+                repeat(2) {
                     val vm = hypervisor.createMachine(machineModel)
 
                     launch {
                         try {
-                            vm.run(state.workloads[i])
+                            vm.run(SimTraceWorkload(state.trace))
                         } finally {
                             machine.close()
                         }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimBareMetalMachine.kt b/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimBareMetalMachine.kt
index 09ee601e..27ebba21 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimBareMetalMachine.kt
+++ b/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimBareMetalMachine.kt
@@ -23,7 +23,6 @@
 package org.opendc.simulator.compute
 
 import kotlinx.coroutines.*
-import kotlinx.coroutines.flow.*
 import org.opendc.simulator.compute.cpufreq.ScalingDriver
 import org.opendc.simulator.compute.cpufreq.ScalingGovernor
 import org.opendc.simulator.compute.model.ProcessingUnit
@@ -60,7 +59,7 @@ public class SimBareMetalMachine(
     /**
      * The [TimerScheduler] to use for scheduling the interrupts.
      */
-    private val scheduler = TimerScheduler<Any>(this.context, clock)
+    private val scheduler = SimResourceSchedulerTrampoline(this.context, clock)
 
     override val cpus: List<SimProcessingUnit> = model.cpus.map { ProcessingUnitImpl(it) }
 
@@ -96,7 +95,6 @@ public class SimBareMetalMachine(
     override fun close() {
         super.close()
 
-        scheduler.close()
         scope.cancel()
     }
 
@@ -107,7 +105,7 @@ public class SimBareMetalMachine(
         /**
          * The actual resource supporting the processing unit.
          */
-        private val source = SimResourceSource(model.frequency, clock, scheduler)
+        private val source = SimResourceSource(model.frequency, scheduler)
 
         override val speed: Double
             get() = source.speed
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimFairShareHypervisor.kt b/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimFairShareHypervisor.kt
index fa677de9..11aec2de 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimFairShareHypervisor.kt
+++ b/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimFairShareHypervisor.kt
@@ -31,13 +31,13 @@ import org.opendc.simulator.resources.*
  *
  * @param listener The hypervisor listener to use.
  */
-public class SimFairShareHypervisor(private val listener: SimHypervisor.Listener? = null) : SimAbstractHypervisor() {
+public class SimFairShareHypervisor(private val scheduler: SimResourceScheduler, private val listener: SimHypervisor.Listener? = null) : SimAbstractHypervisor() {
 
     override fun canFit(model: SimMachineModel, switch: SimResourceSwitch): Boolean = true
 
     override fun createSwitch(ctx: SimMachineContext): SimResourceSwitch {
         return SimResourceSwitchMaxMin(
-            ctx.clock,
+            scheduler,
             object : SimResourceSwitchMaxMin.Listener {
                 override fun onSliceFinish(
                     switch: SimResourceSwitchMaxMin,
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimFairShareHypervisorProvider.kt b/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimFairShareHypervisorProvider.kt
index 02eb6ad0..2ab3ea09 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimFairShareHypervisorProvider.kt
+++ b/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimFairShareHypervisorProvider.kt
@@ -22,11 +22,17 @@
 
 package org.opendc.simulator.compute
 
+import org.opendc.simulator.resources.SimResourceSchedulerTrampoline
+import java.time.Clock
+import kotlin.coroutines.CoroutineContext
+
 /**
  * A [SimHypervisorProvider] for the [SimFairShareHypervisor] implementation.
  */
 public class SimFairShareHypervisorProvider : SimHypervisorProvider {
     override val id: String = "fair-share"
 
-    override fun create(listener: SimHypervisor.Listener?): SimHypervisor = SimFairShareHypervisor(listener)
+    override fun create(context: CoroutineContext, clock: Clock, listener: SimHypervisor.Listener?): SimHypervisor {
+        return SimFairShareHypervisor(SimResourceSchedulerTrampoline(context, clock), listener)
+    }
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimHypervisorProvider.kt b/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimHypervisorProvider.kt
index a5b4526b..b66020f4 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimHypervisorProvider.kt
+++ b/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimHypervisorProvider.kt
@@ -22,6 +22,9 @@
 
 package org.opendc.simulator.compute
 
+import java.time.Clock
+import kotlin.coroutines.CoroutineContext
+
 /**
  * A service provider interface for constructing a [SimHypervisor].
  */
@@ -37,5 +40,5 @@ public interface SimHypervisorProvider {
     /**
      * Create a [SimHypervisor] instance with the specified [listener].
      */
-    public fun create(listener: SimHypervisor.Listener? = null): SimHypervisor
+    public fun create(context: CoroutineContext, clock: Clock, listener: SimHypervisor.Listener? = null): SimHypervisor
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimSpaceSharedHypervisorProvider.kt b/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimSpaceSharedHypervisorProvider.kt
index e2044d05..83b924d7 100644
--- a/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimSpaceSharedHypervisorProvider.kt
+++ b/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimSpaceSharedHypervisorProvider.kt
@@ -22,11 +22,16 @@
 
 package org.opendc.simulator.compute
 
+import java.time.Clock
+import kotlin.coroutines.CoroutineContext
+
 /**
  * A [SimHypervisorProvider] for the [SimSpaceSharedHypervisor] implementation.
  */
 public class SimSpaceSharedHypervisorProvider : SimHypervisorProvider {
     override val id: String = "space-shared"
 
-    override fun create(listener: SimHypervisor.Listener?): SimHypervisor = SimSpaceSharedHypervisor()
+    override fun create(context: CoroutineContext, clock: Clock, listener: SimHypervisor.Listener?): SimHypervisor {
+        return SimSpaceSharedHypervisor()
+    }
 }
diff --git a/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/SimHypervisorTest.kt b/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/SimHypervisorTest.kt
index a067dd2e..8886caa7 100644
--- a/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/SimHypervisorTest.kt
+++ b/opendc-simulator/opendc-simulator-compute/src/test/kotlin/org/opendc/simulator/compute/SimHypervisorTest.kt
@@ -39,6 +39,7 @@ import org.opendc.simulator.compute.model.ProcessingUnit
 import org.opendc.simulator.compute.power.ConstantPowerModel
 import org.opendc.simulator.compute.workload.SimTraceWorkload
 import org.opendc.simulator.core.runBlockingSimulation
+import org.opendc.simulator.resources.SimResourceSchedulerTrampoline
 
 /**
  * Test suite for the [SimHypervisor] class.
@@ -93,7 +94,7 @@ internal class SimHypervisorTest {
             )
 
         val machine = SimBareMetalMachine(coroutineContext, clock, model, PerformanceScalingGovernor(), SimpleScalingDriver(ConstantPowerModel(0.0)))
-        val hypervisor = SimFairShareHypervisor(listener)
+        val hypervisor = SimFairShareHypervisor(SimResourceSchedulerTrampoline(coroutineContext, clock), listener)
 
         launch {
             machine.run(hypervisor)
@@ -167,7 +168,7 @@ internal class SimHypervisorTest {
             coroutineContext, clock, model, PerformanceScalingGovernor(),
             SimpleScalingDriver(ConstantPowerModel(0.0))
         )
-        val hypervisor = SimFairShareHypervisor(listener)
+        val hypervisor = SimFairShareHypervisor(SimResourceSchedulerTrampoline(coroutineContext, clock), listener)
 
         launch {
             machine.run(hypervisor)