sim: Implement energy models from CloudSim (#79)

This commit implements the energy models that are present in CloudSim:
1. Constant
2. Linear
3. Cubic
4. Square root
5. Interpolation based on data.

14 files changed, 286 insertions, 81 deletions

diff --git a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/SimBareMetalDriver.kt b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/SimBareMetalDriver.kt
index 7a978a53..1e459e6f 100644
--- a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/SimBareMetalDriver.kt
+++ b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/SimBareMetalDriver.kt
@@ -34,9 +34,9 @@ import org.opendc.compute.core.metal.Node
 import org.opendc.compute.core.metal.NodeEvent
 import org.opendc.compute.core.metal.NodeState
 import org.opendc.compute.core.metal.driver.BareMetalDriver
-import org.opendc.compute.simulator.power.ConstantPowerModel
-import org.opendc.compute.simulator.power.PowerModel
-import org.opendc.compute.simulator.power.Powerable
+import org.opendc.compute.simulator.power.api.CpuPowerModel
+import org.opendc.compute.simulator.power.api.Powerable
+import org.opendc.compute.simulator.power.models.ConstantPowerModel
 import org.opendc.core.services.ServiceRegistry
 import org.opendc.simulator.compute.SimBareMetalMachine
 import org.opendc.simulator.compute.SimExecutionContext
@@ -59,7 +59,7 @@ import kotlin.random.Random
  * @param name An optional name of the machine.
  * @param metadata The initial metadata of the node.
  * @param machine The machine model to simulate.
- * @param powerModel The power model of this machine.
+ * @param cpuPowerModel The CPU power model of this machine.
  */
 @OptIn(ExperimentalCoroutinesApi::class)
 public class SimBareMetalDriver(
@@ -69,7 +69,7 @@ public class SimBareMetalDriver(
     name: String,
     metadata: Map<String, Any>,
     machine: SimMachineModel,
-    powerModel: PowerModel<SimBareMetalDriver> = ConstantPowerModel(0.0)
+    cpuPowerModel: CpuPowerModel = ConstantPowerModel(0.0),
 ) : BareMetalDriver, FailureDomain, Powerable {
     /**
      * The flavor that corresponds to this machine.
@@ -100,7 +100,7 @@ public class SimBareMetalDriver(
     override val usage: Flow<Double>
         get() = this.machine.usage
 
-    override val powerDraw: Flow<Double> = powerModel(this)
+    override val powerDraw: Flow<Double> = cpuPowerModel.getPowerDraw(this)
 
     /**
      * The internal random instance.
diff --git a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/PowerModel.kt b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/PowerModel.kt
deleted file mode 100644
index 174a510b..00000000
--- a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/PowerModel.kt
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * MIT License
- *
- * Copyright (c) 2020 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.compute.simulator.power
-
-import kotlinx.coroutines.flow.Flow
-
-/**
- * A model for computing the power draw based on some value.
- */
-public typealias PowerModel<T> = (T) -> Flow<Double>
diff --git a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/PowerModels.kt b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/PowerModels.kt
deleted file mode 100644
index 651eba6e..00000000
--- a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/PowerModels.kt
+++ /dev/null
@@ -1,42 +0,0 @@
-/*
- * Copyright (c) 2020 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.compute.simulator.power
-
-import kotlinx.coroutines.flow.flowOf
-import kotlinx.coroutines.flow.map
-import org.opendc.compute.core.metal.driver.BareMetalDriver
-
-/**
- * A power model which emits a single value.
- */
-public fun ConstantPowerModel(value: Double): PowerModel<BareMetalDriver> = { _ -> flowOf(value) }
-
-/**
- * A power model that assumes a naive linear relation between power usage and host CPU utilization.
- *
- * @param idle The power draw in Watts on idle.
- * @param max The maximum power draw in Watts of the server.
- */
-public fun LinearLoadPowerModel(idle: Double, max: Double): PowerModel<BareMetalDriver> = { driver ->
-    driver.usage.map { load -> (max - idle) * load + idle }
-}
diff --git a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/api/CpuPowerModel.kt b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/api/CpuPowerModel.kt
new file mode 100644
index 00000000..ee9e130b
--- /dev/null
+++ b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/api/CpuPowerModel.kt
@@ -0,0 +1,31 @@
+package org.opendc.compute.simulator.power.api
+
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.map
+import org.opendc.compute.core.metal.driver.BareMetalDriver
+
+public interface CpuPowerModel {
+    /**
+     * Computes CPU power consumption for each host.
+     *
+     * @param cpuUtil The CPU utilization percentage.
+     * @return A [Double] value of CPU power consumption.
+     * @throws IllegalArgumentException Will throw an error if [cpuUtil] is out of range.
+     */
+    @Throws(IllegalArgumentException::class)
+    public fun computeCpuPower(cpuUtil: Double): Double
+
+    /**
+     * Emits the values of power consumption for servers.
+     *
+     * @param driver A [BareMetalDriver] that offers host CPU utilization.
+     * @param withoutIdle A [Boolean] flag indicates whether (false) add a constant
+     *                  power consumption value when the server is idle or (true) not
+     *                  with a default value being false.
+     * @return A [Flow] of values representing the server power draw.
+     */
+    public fun getPowerDraw(driver: BareMetalDriver, withoutIdle: Boolean = false): Flow<Double> =
+        driver.usage.map {
+            computeCpuPower(it)
+        }
+}
diff --git a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/Powerable.kt b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/api/Powerable.kt
index dcf74468..780f2a29 100644
--- a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/Powerable.kt
+++ b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/api/Powerable.kt
@@ -22,7 +22,7 @@
  * SOFTWARE.
  */
 
-package org.opendc.compute.simulator.power
+package org.opendc.compute.simulator.power.api
 
 import kotlinx.coroutines.flow.Flow
 
diff --git a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/ConstantPowerModel.kt b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/ConstantPowerModel.kt
new file mode 100644
index 00000000..5e80827b
--- /dev/null
+++ b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/ConstantPowerModel.kt
@@ -0,0 +1,10 @@
+package org.opendc.compute.simulator.power.models
+
+import org.opendc.compute.simulator.power.api.CpuPowerModel
+
+/**
+ * A power model which produces a constant value [constant].
+ */
+public class ConstantPowerModel(private val constant: Double) : CpuPowerModel {
+    public override fun computeCpuPower(cpuUtil: Double): Double = constant
+}
diff --git a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/CubicPowerModel.kt b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/CubicPowerModel.kt
new file mode 100644
index 00000000..9008a987
--- /dev/null
+++ b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/CubicPowerModel.kt
@@ -0,0 +1,26 @@
+package org.opendc.compute.simulator.power.models
+
+import org.opendc.compute.simulator.power.api.CpuPowerModel
+import kotlin.math.pow
+
+/**
+ * The cubic power model partially adapted from CloudSim.
+ *
+ * @param maxPower The maximum power draw in Watts of the server.
+ * @param staticPowerPercent The static power percentage.
+ * @property staticPower The static power consumption that is not dependent on resource usage.
+ *                      It is the amount of energy consumed even when the host is idle.
+ * @property constPower The constant power consumption for each fraction of resource used.
+ */
+public class CubicPowerModel(
+    private var maxPower: Double,
+    staticPowerPercent: Double
+) : CpuPowerModel {
+    private var staticPower: Double = staticPowerPercent * maxPower
+    private var constPower: Double = (maxPower - staticPower) / 100.0.pow(3)
+
+    public override fun computeCpuPower(cpuUtil: Double): Double {
+        require(cpuUtil in 0.0..1.0) { "CPU utilization must be in [0, 1]" }
+        return staticPower + constPower * (cpuUtil * 100).pow(3)
+    }
+}
diff --git a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/InterpolationPowerModel.kt b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/InterpolationPowerModel.kt
new file mode 100644
index 00000000..b01957e4
--- /dev/null
+++ b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/InterpolationPowerModel.kt
@@ -0,0 +1,34 @@
+package org.opendc.compute.simulator.power.models
+
+import org.opendc.compute.simulator.power.api.CpuPowerModel
+import kotlin.math.ceil
+import kotlin.math.floor
+
+/**
+ * The linear interpolation power model partially adapted from CloudSim.
+ *
+ * @param maxPower The maximum power draw in Watts of the server.
+ * @param staticPowerPercent The static power percentage.
+ * @property staticPower The static power consumption that is not dependent on resource usage.
+ *                      It is the amount of energy consumed even when the host is idle.
+ * @property constPower The constant power consumption for each fraction of resource used.
+ */
+public abstract class InterpolationPowerModel : CpuPowerModel {
+
+    public override fun computeCpuPower(cpuUtil: Double): Double {
+        require(cpuUtil in 0.0..1.0) { "CPU utilization must be in [0, 1]" }
+
+        val cpuUtilFlr = floor(cpuUtil * 10).toInt()
+        val cpuUtilCil = ceil(cpuUtil * 10).toInt()
+        val power1: Double = getPowerData(cpuUtilFlr)
+        val power2: Double = getPowerData(cpuUtilCil)
+        val delta = (power2 - power1) / 10
+
+        return if (cpuUtil % 0.1 == 0.0)
+            getPowerData((cpuUtil * 10).toInt())
+        else
+            power1 + delta * (cpuUtil - cpuUtilFlr.toDouble() / 10) * 100
+    }
+
+    public abstract fun getPowerData(index: Int): Double
+}
diff --git a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/LinearPowerModel.kt b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/LinearPowerModel.kt
new file mode 100644
index 00000000..913095ad
--- /dev/null
+++ b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/LinearPowerModel.kt
@@ -0,0 +1,25 @@
+package org.opendc.compute.simulator.power.models
+
+import org.opendc.compute.simulator.power.api.CpuPowerModel
+
+/**
+ * The linear power model partially adapted from CloudSim.
+ *
+ * @param maxPower The maximum power draw in Watts of the server.
+ * @param staticPowerPercent The static power percentage.
+ * @property staticPower The static power consumption that is not dependent on resource usage.
+ *                      It is the amount of energy consumed even when the host is idle.
+ * @property constPower The constant power consumption for each fraction of resource used.
+ */
+public class LinearPowerModel(
+    private var maxPower: Double,
+    staticPowerPercent: Double
+) : CpuPowerModel {
+    private var staticPower: Double = staticPowerPercent * maxPower
+    private var constPower: Double = (maxPower - staticPower) / 100
+
+    public override fun computeCpuPower(cpuUtil: Double): Double {
+        require(cpuUtil in 0.0..1.0) { "CPU utilization must be in [0, 1]" }
+        return staticPower + constPower * cpuUtil * 100
+    }
+}
diff --git a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/SqrtPowerModel.kt b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/SqrtPowerModel.kt
new file mode 100644
index 00000000..85d94ffc
--- /dev/null
+++ b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/SqrtPowerModel.kt
@@ -0,0 +1,26 @@
+package org.opendc.compute.simulator.power.models
+
+import org.opendc.compute.simulator.power.api.CpuPowerModel
+import kotlin.math.sqrt
+
+/**
+ * The square root power model partially adapted from CloudSim.
+ *
+ * @param maxPower The maximum power draw in Watts of the server.
+ * @param staticPowerPercent The static power percentage.
+ * @property staticPower The static power consumption that is not dependent on resource usage.
+ *                      It is the amount of energy consumed even when the host is idle.
+ * @property constPower The constant power consumption for each fraction of resource used.
+ */
+public class SqrtPowerModel(
+    private var maxPower: Double,
+    staticPowerPercent: Double
+) : CpuPowerModel {
+    private var staticPower: Double = staticPowerPercent * maxPower
+    private var constPower: Double = (maxPower - staticPower) / sqrt(100.0)
+
+    override fun computeCpuPower(cpuUtil: Double): Double {
+        require(cpuUtil in 0.0..1.0) { "CPU utilization must be in [0, 1]" }
+        return staticPower + constPower * sqrt(cpuUtil * 100)
+    }
+}
diff --git a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/SquarePowerModel.kt b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/SquarePowerModel.kt
new file mode 100644
index 00000000..5f44aa3c
--- /dev/null
+++ b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/SquarePowerModel.kt
@@ -0,0 +1,26 @@
+package org.opendc.compute.simulator.power.models
+
+import org.opendc.compute.simulator.power.api.CpuPowerModel
+import kotlin.math.pow
+
+/**
+ * The square power model partially adapted from CloudSim.
+ *
+ * @param maxPower The maximum power draw in Watts of the server.
+ * @param staticPowerPercent The static power percentage.
+ * @property staticPower The static power consumption that is not dependent on resource usage.
+ *                      It is the amount of energy consumed even when the host is idle.
+ * @property constPower The constant power consumption for each fraction of resource used.
+ */
+public class SquarePowerModel(
+    private var maxPower: Double,
+    staticPowerPercent: Double
+) : CpuPowerModel {
+    private var staticPower: Double = staticPowerPercent * maxPower
+    private var constPower: Double = (maxPower - staticPower) / 100.0.pow(2)
+
+    override fun computeCpuPower(cpuUtil: Double): Double {
+        require(cpuUtil in 0.0..1.0) { "CPU utilization must be in [0, 1]" }
+        return staticPower + constPower * (cpuUtil * 100).pow(2)
+    }
+}
diff --git a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/ZeroIdlePowerDecorator.kt b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/ZeroIdlePowerDecorator.kt
new file mode 100644
index 00000000..938e5607
--- /dev/null
+++ b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/ZeroIdlePowerDecorator.kt
@@ -0,0 +1,14 @@
+package org.opendc.compute.simulator.power.models
+
+import org.opendc.compute.simulator.power.api.CpuPowerModel
+
+/**
+ * A decorator for ignoring the idle power when computing energy consumption of components.
+ *
+ * @param cpuModelWrappee The wrappe of a [CpuPowerModel].
+ */
+public class ZeroIdlePowerDecorator(private val cpuModelWrappee: CpuPowerModel) : CpuPowerModel {
+    override fun computeCpuPower(cpuUtil: Double): Double {
+        return if (cpuUtil == 0.0) 0.0 else cpuModelWrappee.computeCpuPower(cpuUtil)
+    }
+}
diff --git a/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/package-info.java b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/package-info.java
new file mode 100644
index 00000000..9354f1f9
--- /dev/null
+++ b/simulator/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/power/models/package-info.java
@@ -0,0 +1,12 @@
+/**
+ * Contains a set of energy models, which are developed based on that of the following cloud simulators.
+ * N.B. Different configurations and new features may have been introduced.
+ *
+ * CloudSim:
+ * @see <a href="http://dx.doi.org/10.1002/cpe.1867">Anton Beloglazov, and Rajkumar Buyya, "Optimal Online Deterministic
+ * Algorithms and Adaptive Heuristics for Energy and Performance Efficient Dynamic Consolidation of Virtual Machines in
+ * Cloud Data Centers", Concurrency and Computation: Practice and Experience (CCPE), Volume 24,
+ * Issue 13, Pages: 1397-1420, John Wiley & Sons, Ltd, New York, USA, 2012</a>
+ */
+package org.opendc.compute.simulator.power.models;
+// rest of the file is empty
diff --git a/simulator/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/power/CpuPowerModelTest.kt b/simulator/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/power/CpuPowerModelTest.kt
new file mode 100644
index 00000000..7b0c7515
--- /dev/null
+++ b/simulator/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/power/CpuPowerModelTest.kt
@@ -0,0 +1,75 @@
+package org.opendc.compute.simulator.power
+
+import io.mockk.*
+import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.runBlocking
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.Arguments
+import org.junit.jupiter.params.provider.MethodSource
+import org.opendc.compute.core.metal.driver.BareMetalDriver
+import org.opendc.compute.simulator.power.api.CpuPowerModel
+import org.opendc.compute.simulator.power.models.*
+import java.util.stream.Stream
+import kotlin.math.pow
+
+internal class CpuPowerModelTest {
+    private val epsilon = 10.0.pow(-3)
+    private val cpuUtil = .9
+
+    @ParameterizedTest
+    @MethodSource("cpuPowerModelArgs")
+    fun `compute power consumption given CPU loads`(
+        powerModel: CpuPowerModel,
+        expectedPowerConsumption: Double
+    ) {
+        val computedPowerConsumption = powerModel.computeCpuPower(cpuUtil)
+        assertEquals(expectedPowerConsumption, computedPowerConsumption, epsilon)
+    }
+
+    @ParameterizedTest
+    @MethodSource("cpuPowerModelArgs")
+    fun `ignore idle power when computing power consumptions`(
+        powerModel: CpuPowerModel,
+        expectedPowerConsumption: Double
+    ) {
+        val zeroPowerModel = ZeroIdlePowerDecorator(powerModel)
+        val computedPowerConsumption = zeroPowerModel.computeCpuPower(0.0)
+        assertEquals(0.0, computedPowerConsumption)
+    }
+
+    @ParameterizedTest
+    @MethodSource("cpuPowerModelArgs")
+    fun `emit power draw for hosts by different models`(
+        powerModel: CpuPowerModel,
+        expectedPowerConsumption: Double
+    ) {
+        val cpuLoads = flowOf(cpuUtil, cpuUtil, cpuUtil)
+        val bareMetalDriver = mockkClass(BareMetalDriver::class)
+        every { bareMetalDriver.usage } returns cpuLoads
+
+        runBlocking {
+            val serverPowerDraw = powerModel.getPowerDraw(bareMetalDriver)
+
+            assertEquals(serverPowerDraw.count(), cpuLoads.count())
+            assertEquals(
+                serverPowerDraw.first().toDouble(),
+                flowOf(expectedPowerConsumption).first().toDouble(),
+                epsilon
+            )
+        }
+        verify(exactly = 1) { bareMetalDriver.usage }
+    }
+
+    @Suppress("unused")
+    private companion object {
+        @JvmStatic
+        fun cpuPowerModelArgs(): Stream<Arguments> = Stream.of(
+            Arguments.of(ConstantPowerModel(0.0), 0.0),
+            Arguments.of(LinearPowerModel(350.0, 200 / 350.0), 335.0),
+            Arguments.of(SquarePowerModel(350.0, 200 / 350.0), 321.5),
+            Arguments.of(CubicPowerModel(350.0, 200 / 350.0), 309.35),
+            Arguments.of(SqrtPowerModel(350.0, 200 / 350.0), 342.302),
+        )
+    }
+}