Memory update (#379)

* Updated the memory usage of Tasks. Still in Progress.

* Merged Task and ServiceTask -> Currently not fully working!!!

* Fixed bugs that made the merger between Task and ServiceTask not work well.

* Updated jdk version for Dockerfile

* Removed ServiceFlavor.java and Task.kt

16 files changed, 70 insertions, 65 deletions

diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/host/SimHost.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/host/SimHost.kt
index 856cfd3b..cb7d028c 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/host/SimHost.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/host/SimHost.kt
@@ -23,7 +23,6 @@
 package org.opendc.compute.simulator.host
 
 import org.opendc.common.ResourceType
-import org.opendc.compute.api.Flavor
 import org.opendc.compute.api.TaskState
 import org.opendc.compute.simulator.internal.Guest
 import org.opendc.compute.simulator.internal.GuestListener
@@ -231,9 +230,9 @@ public class SimHost(
     }
 
     public fun canFit(task: ServiceTask): Boolean {
-        val sufficientMemory = model.memoryCapacity >= task.flavor.memorySize
-        val enoughCpus = model.coreCount >= task.flavor.cpuCoreCount
-        val canFit = simMachine!!.canFit(task.flavor.toMachineModel())
+        val sufficientMemory = model.memoryCapacity >= task.memorySize
+        val enoughCpus = model.coreCount >= task.cpuCoreCount
+        val canFit = simMachine!!.canFit(task.toMachineModel())
 
         return sufficientMemory && enoughCpus && canFit
     }
@@ -404,10 +403,10 @@ public class SimHost(
     /**
      * Convert flavor to machine model.
      */
-    private fun Flavor.toMachineModel(): MachineModel {
+    private fun ServiceTask.toMachineModel(): MachineModel {
         return MachineModel(
             simMachine!!.machineModel.cpuModel,
-            MemoryUnit("Generic", "Generic", 3200.0, memorySize),
+            MemoryUnit("Generic", "Generic", 3200.0, this.memorySize),
             simMachine!!.machineModel.gpuModels,
             simMachine!!.machineModel.cpuDistributionStrategy,
             simMachine!!.machineModel.gpuDistributionStrategy,
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/DifferentHostFilter.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/DifferentHostFilter.kt
index bc98a575..9d0006a4 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/DifferentHostFilter.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/DifferentHostFilter.kt
@@ -34,7 +34,8 @@ public class DifferentHostFilter : HostFilter {
         task: ServiceTask,
     ): Boolean {
         @Suppress("UNCHECKED_CAST")
-        val affinityIDs = task.meta["scheduler_hint:different_host"] as? Set<Int> ?: return true
-        return host.host.getInstances().none { it.id in affinityIDs }
+        return true // TODO: re-enable different_host filter
+//        val affinityIDs = task.meta["scheduler_hint:different_host"] as? Set<Int> ?: return true
+//        return host.host.getInstances().none { it.id in affinityIDs }
     }
 }
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/RamFilter.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/RamFilter.kt
index fcc5e49c..a58cd408 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/RamFilter.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/RamFilter.kt
@@ -37,9 +37,9 @@ public class RamFilter(private val allocationRatio: Double = 1.0) : HostFilter {
         host: HostView,
         task: ServiceTask,
     ): Boolean {
-        if (isSimple) return host.availableMemory >= task.flavor.memorySize
+        if (isSimple) return host.availableMemory >= task.memorySize
 
-        val requestedMemory = task.flavor.memorySize
+        val requestedMemory = task.memorySize
         val availableMemory = host.availableMemory
         val memoryCapacity = host.host.getModel().memoryCapacity
 
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/SameHostFilter.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/SameHostFilter.kt
index 73fd0d3c..8d5048d3 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/SameHostFilter.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/SameHostFilter.kt
@@ -34,7 +34,8 @@ public class SameHostFilter : HostFilter {
         task: ServiceTask,
     ): Boolean {
         @Suppress("UNCHECKED_CAST")
-        val affinityIDs = task.meta["scheduler_hint:same_host"] as? Set<Int> ?: return true
-        return host.host.getInstances().any { it.id in affinityIDs }
+//        val affinityIDs = task.meta["scheduler_hint:same_host"] as? Set<Int> ?: return true
+//        return host.host.getInstances().any { it.id in affinityIDs }
+        return true
     }
 }
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VCpuCapacityFilter.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VCpuCapacityFilter.kt
index 7fa7a051..72d6be97 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VCpuCapacityFilter.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VCpuCapacityFilter.kt
@@ -34,13 +34,10 @@ public class VCpuCapacityFilter : HostFilter {
         host: HostView,
         task: ServiceTask,
     ): Boolean {
-        val requiredCapacity = task.flavor.meta["cpu-capacity"] as? Double
+        val requiredCapacity = task.cpuCapacity
         val availableCapacity = host.host.getModel().cpuCapacity
 
-        return (
-            requiredCapacity == null ||
-                (availableCapacity / host.host.getModel().coreCount)
-                >= (requiredCapacity / task.flavor.cpuCoreCount)
-        )
+        return (availableCapacity / host.host.getModel().coreCount) >=
+            (requiredCapacity / task.cpuCoreCount)
     }
 }
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VCpuFilter.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VCpuFilter.kt
index a017c623..2b66fd17 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VCpuFilter.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VCpuFilter.kt
@@ -37,9 +37,9 @@ public class VCpuFilter(private val allocationRatio: Double = 1.0) : HostFilter
         host: HostView,
         task: ServiceTask,
     ): Boolean {
-        if (isSimple) return host.availableCpuCores >= task.flavor.cpuCoreCount
+        if (isSimple) return host.availableCpuCores >= task.cpuCoreCount
 
-        val requested = task.flavor.cpuCoreCount
+        val requested = task.cpuCoreCount
         val totalCores = host.host.getModel().coreCount
 
         // Do not allow an instance to overcommit against itself, only against other instances
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VGpuCapacityFilter.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VGpuCapacityFilter.kt
index 5f517257..bcb4a066 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VGpuCapacityFilter.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VGpuCapacityFilter.kt
@@ -35,14 +35,11 @@ public class VGpuCapacityFilter : HostFilter {
         host: HostView,
         task: ServiceTask,
     ): Boolean {
-        val requiredCapacity = task.flavor.meta["gpu-capacity"] as? Double
+        val requiredCapacity = task.gpuCapacity
         val availableCapacity = (host.host.getModel().gpuHostModels().maxOfOrNull { it.gpuCoreCapacity() } ?: 0).toDouble()
         val availableCores = (host.host.getModel().gpuHostModels().maxOfOrNull { it -> it.gpuCoreCount } ?: -1).toDouble()
         val availableRatio = availableCapacity / availableCores
 
-        return (
-            requiredCapacity == null ||
-                (availableRatio >= (requiredCapacity / task.flavor.gpuCoreCount))
-        )
+        return availableRatio >= (requiredCapacity / task.gpuCoreCount)
     }
 }
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VGpuFilter.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VGpuFilter.kt
index f47013b1..26855944 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VGpuFilter.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/filters/VGpuFilter.kt
@@ -35,7 +35,7 @@ public class VGpuFilter(private val allocationRatio: Double) : HostFilter {
         host: HostView,
         task: ServiceTask,
     ): Boolean {
-        val requested = task.flavor.gpuCoreCount
+        val requested = task.gpuCoreCount
         val totalCores = host.host.getModel().gpuHostModels()?.sumOf { it.gpuCoreCount() } ?: 0
         val limit = totalCores * allocationRatio
 
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/timeshift/MemorizingTimeshift.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/timeshift/MemorizingTimeshift.kt
index e0488e30..f84d1a4b 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/timeshift/MemorizingTimeshift.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/timeshift/MemorizingTimeshift.kt
@@ -30,7 +30,6 @@ import org.opendc.compute.simulator.scheduler.filters.HostFilter
 import org.opendc.compute.simulator.service.HostView
 import org.opendc.compute.simulator.service.ServiceTask
 import org.opendc.simulator.compute.power.CarbonModel
-import java.time.Instant
 import java.time.InstantSource
 import java.util.LinkedList
 
@@ -126,18 +125,25 @@ public class MemorizingTimeshift(
              Only delay tasks if they are deferrable and it doesn't violate the deadline.
              Separate delay thresholds for short and long tasks.
              */
-            if (task.nature.deferrable) {
-                val durInHours = task.duration.toHours()
+            if (task.deferrable) {
+                val durInHours = task.duration / (1000.0 * 60.0 * 60.0)
                 if ((durInHours < 2 && !shortLowCarbon) ||
                     (durInHours >= 2 && !longLowCarbon)
                 ) {
-                    val currentTime = clock.instant()
-                    val estimatedCompletion = currentTime.plus(task.duration)
-                    val deadline = Instant.ofEpochMilli(task.deadline)
-                    if (estimatedCompletion.isBefore(deadline)) {
+                    val currentTime = clock.millis()
+                    val estimatedCompletion = currentTime + task.duration
+                    val deadline = task.deadline
+                    if (estimatedCompletion <= deadline) {
                         // No need to schedule this task in a high carbon intensity period
                         continue
                     }
+//                    val currentTime = clock.instant()
+//                    val estimatedCompletion = currentTime.plus(task.duration)
+//                    val deadline = Instant.ofEpochMilli(task.deadline)
+//                    if (estimatedCompletion.isBefore(deadline)) {
+//                        // No need to schedule this task in a high carbon intensity period
+//                        continue
+//                    }
                 }
             }
 
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/timeshift/TimeshiftScheduler.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/timeshift/TimeshiftScheduler.kt
index 58b8904b..535336e8 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/timeshift/TimeshiftScheduler.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/timeshift/TimeshiftScheduler.kt
@@ -31,7 +31,6 @@ import org.opendc.compute.simulator.scheduler.weights.HostWeigher
 import org.opendc.compute.simulator.service.HostView
 import org.opendc.compute.simulator.service.ServiceTask
 import org.opendc.simulator.compute.power.CarbonModel
-import java.time.Instant
 import java.time.InstantSource
 import java.util.LinkedList
 import java.util.SplittableRandom
@@ -96,15 +95,15 @@ public class TimeshiftScheduler(
              Only delay tasks if they are deferrable and it doesn't violate the deadline.
              Separate delay thresholds for short and long tasks.
              */
-            if (task.nature.deferrable) {
-                val durInHours = task.duration.toHours()
+            if (task.deferrable) {
+                val durInHours = task.duration / (1000.0 * 60.0 * 60.0)
                 if ((durInHours < 2 && !shortLowCarbon) ||
                     (durInHours >= 2 && !longLowCarbon)
                 ) {
-                    val currentTime = clock.instant()
-                    val estimatedCompletion = currentTime.plus(task.duration)
-                    val deadline = Instant.ofEpochMilli(task.deadline)
-                    if (estimatedCompletion.isBefore(deadline)) {
+                    val currentTime = clock.millis()
+                    val estimatedCompletion = currentTime + task.duration
+                    val deadline = task.deadline
+                    if (estimatedCompletion < deadline) {
                         // No need to schedule this task in a high carbon intensity period
                         continue
                     }
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/weights/VCpuCapacityWeigher.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/weights/VCpuCapacityWeigher.kt
index d9b094fb..65cc66a7 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/weights/VCpuCapacityWeigher.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/weights/VCpuCapacityWeigher.kt
@@ -34,8 +34,8 @@ public class VCpuCapacityWeigher(override val multiplier: Double = 1.0) : HostWe
         task: ServiceTask,
     ): Double {
         val model = host.host.getModel()
-        val requiredCapacity = task.flavor.meta["cpu-capacity"] as? Double ?: 0.0
-        return model.cpuCapacity - requiredCapacity / task.flavor.cpuCoreCount
+        val requiredCapacity = task.cpuCapacity
+        return model.cpuCapacity - requiredCapacity / task.cpuCoreCount
     }
 
     override fun toString(): String = "VCpuWeigher"
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/weights/VGpuCapacityWeigher.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/weights/VGpuCapacityWeigher.kt
index 35f2c7b9..78c49271 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/weights/VGpuCapacityWeigher.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/scheduler/weights/VGpuCapacityWeigher.kt
@@ -34,9 +34,9 @@ public class VGpuCapacityWeigher(override val multiplier: Double = 1.0) : HostWe
         task: ServiceTask,
     ): Double {
         val model = host.host.getModel()
-        val requiredCapacity = task.flavor.meta["gpu-capacity"] as? Double ?: 0.0
+        val requiredCapacity = task.gpuCapacity
         val availableCapacity = model.gpuHostModels.maxOfOrNull { it.gpuCoreCapacity } ?: 0.0
-        return availableCapacity - requiredCapacity / task.flavor.gpuCoreCount
+        return availableCapacity - requiredCapacity / task.gpuCoreCount
     }
 
     override fun toString(): String = "VGpuWeigher"
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/parquet/DfltTaskExportColumns.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/parquet/DfltTaskExportColumns.kt
index 0397b9a1..b88c75e6 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/parquet/DfltTaskExportColumns.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/parquet/DfltTaskExportColumns.kt
@@ -71,7 +71,12 @@ public object DfltTaskExportColumns {
                 Types.required(BINARY)
                     .`as`(LogicalTypeAnnotation.stringType())
                     .named("task_name"),
-        ) { Binary.fromString(it.taskInfo.name) }
+        ) {
+            if (it.taskInfo.name == null) {
+                return@ExportColumn Binary.fromString("")
+            }
+            return@ExportColumn Binary.fromString(it.taskInfo.name)
+        }
 
     public val HOST_NAME: ExportColumn<TaskTableReader> =
         ExportColumn(
@@ -194,17 +199,17 @@ public object DfltTaskExportColumns {
     public val SCHEDULE_TIME: ExportColumn<TaskTableReader> =
         ExportColumn(
             field = Types.optional(INT64).named("schedule_time"),
-        ) { it.scheduleTime?.toEpochMilli() }
+        ) { it.scheduleTime }
 
     public val SUBMISSION_TIME: ExportColumn<TaskTableReader> =
         ExportColumn(
             field = Types.optional(INT64).named("submission_time"),
-        ) { it.submissionTime?.toEpochMilli() }
+        ) { it.submissionTime }
 
     public val FINISH_TIME: ExportColumn<TaskTableReader> =
         ExportColumn(
             field = Types.optional(INT64).named("finish_time"),
-        ) { it.finishTime?.toEpochMilli() }
+        ) { it.finishTime }
 
     public val TASK_STATE: ExportColumn<TaskTableReader> =
         ExportColumn(
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/table/task/TaskInfo.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/table/task/TaskInfo.kt
index 2727847f..c23f3fb5 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/table/task/TaskInfo.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/table/task/TaskInfo.kt
@@ -27,7 +27,7 @@ package org.opendc.compute.simulator.telemetry.table.task
  */
 public data class TaskInfo(
     val id: Int,
-    val name: String,
+    val name: String?,
     val type: String,
     val arch: String,
     val cpuCount: Int,
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/table/task/TaskTableReader.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/table/task/TaskTableReader.kt
index e3860606..1f18ee50 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/table/task/TaskTableReader.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/table/task/TaskTableReader.kt
@@ -83,17 +83,17 @@ public interface TaskTableReader : Exportable {
     /**
      * The [Instant] at which the task was scheduled relative to the start of the workload.
      */
-    public val scheduleTime: Instant?
+    public val scheduleTime: Long?
 
     /**
      * The [Instant] at which the task was submitted relative to the start of the workload.
      */
-    public val submissionTime: Instant?
+    public val submissionTime: Long?
 
     /**
      * The [Instant] at which the task finished relative to the start of the workload.
      */
-    public val finishTime: Instant?
+    public val finishTime: Long?
 
     /**
      * The capacity of the CPUs of Host on which the task is running (in MHz).
diff --git a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/table/task/TaskTableReaderImpl.kt b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/table/task/TaskTableReaderImpl.kt
index 3183cf11..d4d5c7a6 100644
--- a/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/table/task/TaskTableReaderImpl.kt
+++ b/opendc-compute/opendc-compute-simulator/src/main/kotlin/org/opendc/compute/simulator/telemetry/table/task/TaskTableReaderImpl.kt
@@ -93,9 +93,9 @@ public class TaskTableReaderImpl(
             task.name,
             "vm",
             "x86",
-            task.flavor.cpuCoreCount,
-            task.flavor.memorySize,
-            task.flavor.gpuCoreCount,
+            task.cpuCoreCount,
+            task.memorySize,
+            task.gpuCoreCount,
         )
 
     /**
@@ -134,17 +134,17 @@ public class TaskTableReaderImpl(
         get() = _numPauses
     private var _numPauses = 0
 
-    override val submissionTime: Instant?
+    override val submissionTime: Long?
         get() = _submissionTime
-    private var _submissionTime: Instant? = null
+    private var _submissionTime: Long? = null
 
-    override val scheduleTime: Instant?
+    override val scheduleTime: Long?
         get() = _scheduleTime
-    private var _scheduleTime: Instant? = null
+    private var _scheduleTime: Long? = null
 
-    override val finishTime: Instant?
+    override val finishTime: Long?
         get() = _finishTime
-    private var _finishTime: Instant? = null
+    private var _finishTime: Long? = null
 
     override val cpuLimit: Double
         get() = _cpuLimit
@@ -190,22 +190,22 @@ public class TaskTableReaderImpl(
         get() = _gpuDemand
     private var _gpuDemand: Double? = 0.0
 
-    override val gpuActiveTime: Long?
+    override val gpuActiveTime: Long
         get() = (_gpuActiveTime ?: 0L) - (previousGpuActiveTime ?: 0L)
     private var _gpuActiveTime: Long? = null
     private var previousGpuActiveTime: Long? = null
 
-    override val gpuIdleTime: Long?
+    override val gpuIdleTime: Long
         get() = (_gpuIdleTime ?: 0L) - (previousGpuIdleTime ?: 0L)
     private var _gpuIdleTime: Long? = null
     private var previousGpuIdleTime: Long? = null
 
-    override val gpuStealTime: Long?
+    override val gpuStealTime: Long
         get() = (_gpuStealTime ?: 0L) - (previousGpuStealTime ?: 0L)
     private var _gpuStealTime: Long? = null
     private var previousGpuStealTime: Long? = null
 
-    override val gpuLostTime: Long?
+    override val gpuLostTime: Long
         get() = (_gpuLostTime ?: 0L) - (previousGpuLostTime ?: 0L)
     private var _gpuLostTime: Long? = null
     private var previousGpuLostTime: Long? = null