-import { DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS } from '../../utils'
+import { cpus } from 'node:os'
+import {
+ DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS,
+ DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
+} from '../../utils'
import type { IPool } from '../pool'
import type { IWorker } from '../worker'
import type {
IWorkerChoiceStrategy,
- RequiredStatistics,
+ MeasurementStatisticsRequirements,
+ StrategyPolicy,
+ TaskStatisticsRequirements,
WorkerChoiceStrategyOptions
} from './selection-strategies-types'
* Worker choice strategy abstract base class.
*
* @typeParam Worker - Type of worker which manages the strategy.
- * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
- * @typeParam Response - Type of execution response. This can only be serializable data.
+ * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
+ * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
*/
export abstract class AbstractWorkerChoiceStrategy<
Worker extends IWorker,
Response = unknown
> implements IWorkerChoiceStrategy {
/**
- * Toggles finding the last free worker node key.
+ * The next worker node key.
*/
- private toggleFindLastFreeWorkerNodeKey: boolean = false
+ protected nextWorkerNodeKey: number | undefined = 0
+
+ /**
+ * The previous worker node key.
+ */
+ protected previousWorkerNodeKey: number = 0
+
+ /** @inheritDoc */
+ public readonly strategyPolicy: StrategyPolicy = {
+ dynamicWorkerUsage: false,
+ dynamicWorkerReady: true
+ }
+
/** @inheritDoc */
- public readonly requiredStatistics: RequiredStatistics = {
- runTime: false,
- avgRunTime: false,
- medRunTime: false
+ public readonly taskStatisticsRequirements: TaskStatisticsRequirements = {
+ runTime: DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS,
+ waitTime: DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS,
+ elu: DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS
}
/**
protected readonly pool: IPool<Worker, Data, Response>,
protected opts: WorkerChoiceStrategyOptions = DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
) {
+ this.opts = { ...DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS, ...opts }
this.choose = this.choose.bind(this)
}
- protected setRequiredStatistics (opts: WorkerChoiceStrategyOptions): void {
- if (this.requiredStatistics.avgRunTime && opts.medRunTime === true) {
- this.requiredStatistics.avgRunTime = false
- this.requiredStatistics.medRunTime = opts.medRunTime as boolean
+ protected setTaskStatisticsRequirements (
+ opts: WorkerChoiceStrategyOptions
+ ): void {
+ this.toggleMedianMeasurementStatisticsRequirements(
+ this.taskStatisticsRequirements.runTime,
+ opts.runTime?.median as boolean
+ )
+ this.toggleMedianMeasurementStatisticsRequirements(
+ this.taskStatisticsRequirements.waitTime,
+ opts.waitTime?.median as boolean
+ )
+ this.toggleMedianMeasurementStatisticsRequirements(
+ this.taskStatisticsRequirements.elu,
+ opts.elu?.median as boolean
+ )
+ }
+
+ private toggleMedianMeasurementStatisticsRequirements (
+ measurementStatisticsRequirements: MeasurementStatisticsRequirements,
+ toggleMedian: boolean
+ ): void {
+ if (measurementStatisticsRequirements.average && toggleMedian) {
+ measurementStatisticsRequirements.average = false
+ measurementStatisticsRequirements.median = toggleMedian
}
- if (this.requiredStatistics.medRunTime && opts.medRunTime === false) {
- this.requiredStatistics.avgRunTime = true
- this.requiredStatistics.medRunTime = opts.medRunTime as boolean
+ if (measurementStatisticsRequirements.median && !toggleMedian) {
+ measurementStatisticsRequirements.average = true
+ measurementStatisticsRequirements.median = toggleMedian
}
}
+ protected resetWorkerNodeKeyProperties (): void {
+ this.nextWorkerNodeKey = 0
+ this.previousWorkerNodeKey = 0
+ }
+
/** @inheritDoc */
public abstract reset (): boolean
public abstract update (workerNodeKey: number): boolean
/** @inheritDoc */
- public abstract choose (): number
+ public abstract choose (): number | undefined
/** @inheritDoc */
public abstract remove (workerNodeKey: number): boolean
/** @inheritDoc */
public setOptions (opts: WorkerChoiceStrategyOptions): void {
- opts = opts ?? DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
- this.setRequiredStatistics(opts)
- this.opts = opts
+ this.opts = { ...DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS, ...opts }
+ this.setTaskStatisticsRequirements(this.opts)
}
/**
- * Finds a free worker node key.
+ * Whether the worker node is ready or not.
*
- * @returns The free worker node key or `-1` if there is no free worker node.
+ * @param workerNodeKey - The worker node key.
+ * @returns Whether the worker node is ready or not.
*/
- protected findFreeWorkerNodeKey (): number {
- if (this.toggleFindLastFreeWorkerNodeKey) {
- this.toggleFindLastFreeWorkerNodeKey = false
- return this.findLastFreeWorkerNodeKey()
- }
- this.toggleFindLastFreeWorkerNodeKey = true
- return this.findFirstFreeWorkerNodeKey()
+ private isWorkerNodeReady (workerNodeKey: number): boolean {
+ return this.pool.workerNodes[workerNodeKey].info.ready
}
/**
- * Gets the worker task run time.
- * If the required statistics are `avgRunTime`, the average run time is returned.
- * If the required statistics are `medRunTime`, the median run time is returned.
+ * Whether the worker node has back pressure or not (i.e. its tasks queue is full).
*
* @param workerNodeKey - The worker node key.
- * @returns The worker task run time.
+ * @returns `true` if the worker node has back pressure, `false` otherwise.
*/
- protected getWorkerTaskRunTime (workerNodeKey: number): number {
- return this.requiredStatistics.medRunTime
- ? this.pool.workerNodes[workerNodeKey].tasksUsage.medRunTime
- : this.pool.workerNodes[workerNodeKey].tasksUsage.avgRunTime
+ private hasWorkerNodeBackPressure (workerNodeKey: number): boolean {
+ return this.pool.hasWorkerNodeBackPressure(workerNodeKey)
}
/**
- * Finds the first free worker node key based on the number of tasks the worker has applied.
- *
- * If a worker is found with `0` running tasks, it is detected as free and its worker node key is returned.
+ * Whether the worker node is eligible or not.
+ * A worker node is eligible if it is ready and does not have back pressure.
*
- * If no free worker is found, `-1` is returned.
+ * @param workerNodeKey - The worker node key.
+ * @returns `true` if the worker node is eligible, `false` otherwise.
+ * @see {@link isWorkerNodeReady}
+ * @see {@link hasWorkerNodeBackPressure}
+ */
+ protected isWorkerNodeEligible (workerNodeKey: number): boolean {
+ return (
+ this.isWorkerNodeReady(workerNodeKey) &&
+ !this.hasWorkerNodeBackPressure(workerNodeKey)
+ )
+ }
+
+ /**
+ * Gets the worker task runtime.
+ * If the task statistics require the average runtime, the average runtime is returned.
+ * If the task statistics require the median runtime , the median runtime is returned.
*
- * @returns A worker node key if there is one, `-1` otherwise.
+ * @param workerNodeKey - The worker node key.
+ * @returns The worker task runtime.
*/
- private findFirstFreeWorkerNodeKey (): number {
- return this.pool.workerNodes.findIndex(workerNode => {
- return workerNode.tasksUsage.running === 0
- })
+ protected getWorkerTaskRunTime (workerNodeKey: number): number {
+ return this.taskStatisticsRequirements.runTime.median
+ ? this.pool.workerNodes[workerNodeKey].usage.runTime?.median ?? 0
+ : this.pool.workerNodes[workerNodeKey].usage.runTime?.average ?? 0
}
/**
- * Finds the last free worker node key based on the number of tasks the worker has applied.
+ * Gets the worker task wait time.
+ * If the task statistics require the average wait time, the average wait time is returned.
+ * If the task statistics require the median wait time, the median wait time is returned.
*
- * If a worker is found with `0` running tasks, it is detected as free and its worker node key is returned.
+ * @param workerNodeKey - The worker node key.
+ * @returns The worker task wait time.
+ */
+ protected getWorkerTaskWaitTime (workerNodeKey: number): number {
+ return this.taskStatisticsRequirements.waitTime.median
+ ? this.pool.workerNodes[workerNodeKey].usage.waitTime?.median ?? 0
+ : this.pool.workerNodes[workerNodeKey].usage.waitTime?.average ?? 0
+ }
+
+ /**
+ * Gets the worker task ELU.
+ * If the task statistics require the average ELU, the average ELU is returned.
+ * If the task statistics require the median ELU, the median ELU is returned.
*
- * If no free worker is found, `-1` is returned.
+ * @param workerNodeKey - The worker node key.
+ * @returns The worker task ELU.
+ */
+ protected getWorkerTaskElu (workerNodeKey: number): number {
+ return this.taskStatisticsRequirements.elu.median
+ ? this.pool.workerNodes[workerNodeKey].usage.elu.active?.median ?? 0
+ : this.pool.workerNodes[workerNodeKey].usage.elu.active?.average ?? 0
+ }
+
+ /**
+ * Sets safely the previous worker node key.
*
- * @returns A worker node key if there is one, `-1` otherwise.
+ * @param workerNodeKey - The worker node key.
+ */
+ protected setPreviousWorkerNodeKey (workerNodeKey: number | undefined): void {
+ this.previousWorkerNodeKey = workerNodeKey ?? this.previousWorkerNodeKey
+ }
+
+ /**
+ * Check the next worker node eligibility.
*/
- private findLastFreeWorkerNodeKey (): number {
- // It requires node >= 18.0.0:
- // return this.workerNodes.findLastIndex(workerNode => {
- // return workerNode.tasksUsage.running === 0
- // })
- for (
- let workerNodeKey = this.pool.workerNodes.length - 1;
- workerNodeKey >= 0;
- workerNodeKey--
- ) {
- if (this.pool.workerNodes[workerNodeKey].tasksUsage.running === 0) {
- return workerNodeKey
- }
+ protected checkNextWorkerNodeEligibility (): void {
+ if (!this.isWorkerNodeEligible(this.nextWorkerNodeKey as number)) {
+ this.nextWorkerNodeKey = undefined
+ }
+ }
+
+ protected computeDefaultWorkerWeight (): number {
+ let cpusCycleTimeWeight = 0
+ for (const cpu of cpus()) {
+ // CPU estimated cycle time
+ const numberOfDigits = cpu.speed.toString().length - 1
+ const cpuCycleTime = 1 / (cpu.speed / Math.pow(10, numberOfDigits))
+ cpusCycleTimeWeight += cpuCycleTime * Math.pow(10, numberOfDigits)
}
- return -1
+ return Math.round(cpusCycleTimeWeight / cpus().length)
}
}