refactor(exp/tf20): Directly expose device stats stats to user

This change updates the `TFDevice` interface to directly expose
statistics about the accelerator device to the user. Previously, the
user had to access these values through OpenTelemetry, which required
substantial extra work.

5 files changed, 63 insertions, 12 deletions

diff --git a/opendc-experiments/opendc-experiments-tf20/build.gradle.kts b/opendc-experiments/opendc-experiments-tf20/build.gradle.kts
index 43093abf..5762ce64 100644
--- a/opendc-experiments/opendc-experiments-tf20/build.gradle.kts
+++ b/opendc-experiments/opendc-experiments-tf20/build.gradle.kts
@@ -36,8 +36,7 @@ dependencies {
     implementation(projects.opendcCommon)
 
     implementation(libs.kotlin.logging)
-    implementation(libs.jackson.module.kotlin) {
-        exclude(group = "org.jetbrains.kotlin", module = "kotlin-reflect")
-    }
-    implementation("org.jetbrains.kotlin:kotlin-reflect:1.6.10")
+    implementation(libs.jackson.module.kotlin)
+
+    testImplementation(libs.slf4j.simple)
 }
diff --git a/opendc-experiments/opendc-experiments-tf20/src/main/kotlin/org/opendc/experiments/tf20/core/SimTFDevice.kt b/opendc-experiments/opendc-experiments-tf20/src/main/kotlin/org/opendc/experiments/tf20/core/SimTFDevice.kt
index 5245261c..99948c8e 100644
--- a/opendc-experiments/opendc-experiments-tf20/src/main/kotlin/org/opendc/experiments/tf20/core/SimTFDevice.kt
+++ b/opendc-experiments/opendc-experiments-tf20/src/main/kotlin/org/opendc/experiments/tf20/core/SimTFDevice.kt
@@ -22,7 +22,6 @@
 
 package org.opendc.experiments.tf20.core
 
-import io.opentelemetry.api.common.AttributeKey
 import io.opentelemetry.api.metrics.Meter
 import kotlinx.coroutines.*
 import org.opendc.simulator.compute.SimBareMetalMachine
@@ -52,7 +51,7 @@ public class SimTFDevice(
     context: CoroutineContext,
     clock: Clock,
     meter: Meter,
-    private val pu: ProcessingUnit,
+    pu: ProcessingUnit,
     private val memory: MemoryUnit,
     powerModel: PowerModel
 ) : TFDevice {
@@ -70,17 +69,13 @@ public class SimTFDevice(
     )
 
     /**
-     * The identifier of a device.
-     */
-    private val deviceId = AttributeKey.stringKey("device.id")
-
-    /**
      * The usage of the device.
      */
     private val _usage = meter.histogramBuilder("device.usage")
         .setDescription("The amount of device resources used")
         .setUnit("MHz")
         .build()
+    private var _resourceUsage = 0.0
 
     /**
      * The power draw of the device.
@@ -89,6 +84,8 @@ public class SimTFDevice(
         .setDescription("The power draw of the device")
         .setUnit("W")
         .build()
+    private var _powerUsage = 0.0
+    private var _energyUsage = 0.0
 
     /**
      * The workload that will be run by the device.
@@ -175,7 +172,10 @@ public class SimTFDevice(
 
         override fun onConverge(conn: FlowConnection, now: Long) {
             _usage.record(conn.rate)
+            _resourceUsage = conn.rate
             _power.record(machine.psu.powerDraw)
+            _powerUsage = machine.powerUsage
+            _energyUsage = machine.energyUsage
         }
     }
 
@@ -197,6 +197,10 @@ public class SimTFDevice(
         }
     }
 
+    override fun getDeviceStats(): TFDeviceStats {
+        return TFDeviceStats(_resourceUsage, _powerUsage, _energyUsage)
+    }
+
     override fun close() {
         machine.cancel()
         scope.cancel()
diff --git a/opendc-experiments/opendc-experiments-tf20/src/main/kotlin/org/opendc/experiments/tf20/core/TFDevice.kt b/opendc-experiments/opendc-experiments-tf20/src/main/kotlin/org/opendc/experiments/tf20/core/TFDevice.kt
index bbc34ed9..839ed8a9 100644
--- a/opendc-experiments/opendc-experiments-tf20/src/main/kotlin/org/opendc/experiments/tf20/core/TFDevice.kt
+++ b/opendc-experiments/opendc-experiments-tf20/src/main/kotlin/org/opendc/experiments/tf20/core/TFDevice.kt
@@ -47,4 +47,9 @@ public interface TFDevice : AutoCloseable {
      * Perform [flops] amount of computation on the device.
      */
     public suspend fun compute(flops: Double)
+
+    /**
+     * Collect device statistics.
+     */
+    public fun getDeviceStats(): TFDeviceStats
 }
diff --git a/opendc-experiments/opendc-experiments-tf20/src/main/kotlin/org/opendc/experiments/tf20/core/TFDeviceStats.kt b/opendc-experiments/opendc-experiments-tf20/src/main/kotlin/org/opendc/experiments/tf20/core/TFDeviceStats.kt
new file mode 100644
index 00000000..016d2a8b
--- /dev/null
+++ b/opendc-experiments/opendc-experiments-tf20/src/main/kotlin/org/opendc/experiments/tf20/core/TFDeviceStats.kt
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2022 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.experiments.tf20.core
+
+/**
+ * Statistics about a TensorFlow [TFDevice].
+ *
+ * @property resourceUsage The resource usage of the device (in MHz).
+ * @property powerUsage The instantaneous power draw of the device (in W).
+ * @property energyUsage Cumulative energy usage of the device since boot (in J).
+ */
+data class TFDeviceStats(
+    val resourceUsage: Double,
+    val powerUsage: Double,
+    val energyUsage: Double
+)
diff --git a/opendc-experiments/opendc-experiments-tf20/src/test/kotlin/org/opendc/experiments/tf20/core/SimTFDeviceTest.kt b/opendc-experiments/opendc-experiments-tf20/src/test/kotlin/org/opendc/experiments/tf20/core/SimTFDeviceTest.kt
index 28a2a319..0d5fbebb 100644
--- a/opendc-experiments/opendc-experiments-tf20/src/test/kotlin/org/opendc/experiments/tf20/core/SimTFDeviceTest.kt
+++ b/opendc-experiments/opendc-experiments-tf20/src/test/kotlin/org/opendc/experiments/tf20/core/SimTFDeviceTest.kt
@@ -25,6 +25,7 @@ package org.opendc.experiments.tf20.core
 import io.opentelemetry.api.metrics.MeterProvider
 import kotlinx.coroutines.coroutineScope
 import kotlinx.coroutines.launch
+import org.junit.jupiter.api.Assertions.assertAll
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Test
 import org.opendc.simulator.compute.model.MemoryUnit
@@ -57,6 +58,12 @@ internal class SimTFDeviceTest {
             launch { device.compute(1e6) }
             launch { device.compute(2e6) }
         }
-        assertEquals(3681, clock.millis())
+
+        val stats = device.getDeviceStats()
+
+        assertAll(
+            { assertEquals(3681, clock.millis()) },
+            { assertEquals(325.75, stats.energyUsage) }
+        )
     }
 }