simulator: Add the CPU power model from iCanCloud/E-mc2

This change implements the CPU energy model with p-states from iCanCloud/E-mc2:

- Only pushed a portion of the code for discussion as not sure if the idea is
  on track.
- Inline comments have been added, and formal documents will follow once the
  model is finalized.
- The p-state power consumptions are currently hard-coded in a companion
  object, which should be improved in the next PR(s).

**Breaking Changes**

- CpuPowerModel: directly interact with the machine it is measuring.
- SimBareMetalMachine: expose the speeds of its CPU cores and its clock
  instant.

1 files changed, 11 insertions, 3 deletions

diff --git a/simulator/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimAbstractMachine.kt b/simulator/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimAbstractMachine.kt
index 1bdbb7e8..39ae34fe 100644
--- a/simulator/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimAbstractMachine.kt
+++ b/simulator/opendc-simulator/opendc-simulator-compute/src/main/kotlin/org/opendc/simulator/compute/SimAbstractMachine.kt
@@ -38,8 +38,6 @@ import kotlin.coroutines.CoroutineContext
 
 /**
  * Abstract implementation of the [SimMachine] interface.
- *
- * @param context The [CoroutineContext] in which the machine runs.
  */
 public abstract class SimAbstractMachine(private val clock: Clock) : SimMachine {
     private val _usage = MutableStateFlow(0.0)
@@ -47,6 +45,13 @@ public abstract class SimAbstractMachine(private val clock: Clock) : SimMachine
         get() = _usage
 
     /**
+     * The speed of the CPU cores.
+     */
+    public val speed: List<Double>
+        get() = _speed
+    private var _speed = mutableListOf<Double>()
+
+    /**
      * A flag to indicate that the machine is terminated.
      */
     private var isTerminated = false
@@ -89,13 +94,16 @@ public abstract class SimAbstractMachine(private val clock: Clock) : SimMachine
         val ctx = Context(resources, meta + mapOf("coroutine-context" to context))
         val totalCapacity = model.cpus.sumByDouble { it.frequency }
 
+        _speed = MutableList(model.cpus.size) { 0.0 }
+
         workload.onStart(ctx)
 
         for ((cpu, source) in resources) {
             val consumer = workload.getConsumer(ctx, cpu)
             val job = source.speed
                 .onEach {
-                    _usage.value = resources.values.sumByDouble { it.speed.value } / totalCapacity
+                    _speed[cpu.id] = source.speed.value
+                    _usage.value = _speed.sum() / totalCapacity
                 }
                 .launchIn(this)