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.

1 files changed, 75 insertions, 0 deletions

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),
+        )
+    }
+}