src/pools/selection-strategies/abstract-worker-choice-strategy.ts

   1 import { cpus } from 'node:os'
   2 import {
   3   DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS,
   4   DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
   5 } from '../../utils'
   6 import type { IPool } from '../pool'
   7 import type { IWorker } from '../worker'
   8 import type {
   9   IWorkerChoiceStrategy,
  10   StrategyPolicy,
  11   TaskStatisticsRequirements,
  12   WorkerChoiceStrategyOptions
  13 } from './selection-strategies-types'
  14
  15 /**
  16  * Worker choice strategy abstract base class.
  17  *
  18  * @typeParam Worker - Type of worker which manages the strategy.
  19  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
  20  * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
  21  */
  22 export abstract class AbstractWorkerChoiceStrategy<
  23   Worker extends IWorker,
  24   Data = unknown,
  25   Response = unknown
  26 > implements IWorkerChoiceStrategy {
  27   // /**
  28   //  * Toggles finding the last free worker node key.
  29   //  */
  30   // private toggleFindLastFreeWorkerNodeKey: boolean = false
  31
  32   /**
  33    * Id of the next worker node.
  34    */
  35   protected nextWorkerNodeId: number = 0
  36
  37   /** @inheritDoc */
  38   public readonly strategyPolicy: StrategyPolicy = {
  39     useDynamicWorker: false
  40   }
  41
  42   /** @inheritDoc */
  43   public readonly taskStatisticsRequirements: TaskStatisticsRequirements = {
  44     runTime: DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS,
  45     waitTime: DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS,
  46     elu: DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS
  47   }
  48
  49   /**
  50    * Constructs a worker choice strategy bound to the pool.
  51    *
  52    * @param pool - The pool instance.
  53    * @param opts - The worker choice strategy options.
  54    */
  55   public constructor (
  56     protected readonly pool: IPool<Worker, Data, Response>,
  57     protected opts: WorkerChoiceStrategyOptions = DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
  58   ) {
  59     this.choose = this.choose.bind(this)
  60   }
  61
  62   protected setTaskStatisticsRequirements (
  63     opts: WorkerChoiceStrategyOptions
  64   ): void {
  65     if (
  66       this.taskStatisticsRequirements.runTime.average &&
  67       opts.runTime?.median === true
  68     ) {
  69       this.taskStatisticsRequirements.runTime.average = false
  70       this.taskStatisticsRequirements.runTime.median = opts.runTime
  71         .median as boolean
  72     }
  73     if (
  74       this.taskStatisticsRequirements.runTime.median &&
  75       opts.runTime?.median === false
  76     ) {
  77       this.taskStatisticsRequirements.runTime.average = true
  78       this.taskStatisticsRequirements.runTime.median = opts.runTime
  79         .median as boolean
  80     }
  81     if (
  82       this.taskStatisticsRequirements.waitTime.average &&
  83       opts.waitTime?.median === true
  84     ) {
  85       this.taskStatisticsRequirements.waitTime.average = false
  86       this.taskStatisticsRequirements.waitTime.median = opts.waitTime
  87         .median as boolean
  88     }
  89     if (
  90       this.taskStatisticsRequirements.waitTime.median &&
  91       opts.waitTime?.median === false
  92     ) {
  93       this.taskStatisticsRequirements.waitTime.average = true
  94       this.taskStatisticsRequirements.waitTime.median = opts.waitTime
  95         .median as boolean
  96     }
  97     if (
  98       this.taskStatisticsRequirements.elu.average &&
  99       opts.elu?.median === true
 100     ) {
 101       this.taskStatisticsRequirements.elu.average = false
 102       this.taskStatisticsRequirements.elu.median = opts.elu.median as boolean
 103     }
 104     if (
 105       this.taskStatisticsRequirements.elu.median &&
 106       opts.elu?.median === false
 107     ) {
 108       this.taskStatisticsRequirements.elu.average = true
 109       this.taskStatisticsRequirements.elu.median = opts.elu.median as boolean
 110     }
 111   }
 112
 113   /** @inheritDoc */
 114   public abstract reset (): boolean
 115
 116   /** @inheritDoc */
 117   public abstract update (workerNodeKey: number): boolean
 118
 119   /** @inheritDoc */
 120   public abstract choose (): number
 121
 122   /** @inheritDoc */
 123   public abstract remove (workerNodeKey: number): boolean
 124
 125   /** @inheritDoc */
 126   public setOptions (opts: WorkerChoiceStrategyOptions): void {
 127     this.opts = opts ?? DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
 128     this.setTaskStatisticsRequirements(this.opts)
 129   }
 130
 131   protected workerNodeReady (workerNodeKey: number): boolean {
 132     return this.pool.workerNodes[workerNodeKey].info.ready
 133   }
 134
 135   // /**
 136   //  * Finds a free worker node key.
 137   //  *
 138   //  * @returns The free worker node key or `-1` if there is no free worker node.
 139   //  */
 140   // protected findFreeWorkerNodeKey (): number {
 141   //   if (this.toggleFindLastFreeWorkerNodeKey) {
 142   //     this.toggleFindLastFreeWorkerNodeKey = false
 143   //     return this.findLastFreeWorkerNodeKey()
 144   //   }
 145   //   this.toggleFindLastFreeWorkerNodeKey = true
 146   //   return this.findFirstFreeWorkerNodeKey()
 147   // }
 148
 149   /**
 150    * Gets the worker task runtime.
 151    * If the task statistics require the average runtime, the average runtime is returned.
 152    * If the task statistics require the median runtime , the median runtime is returned.
 153    *
 154    * @param workerNodeKey - The worker node key.
 155    * @returns The worker task runtime.
 156    */
 157   protected getWorkerTaskRunTime (workerNodeKey: number): number {
 158     return this.taskStatisticsRequirements.runTime.median
 159       ? this.pool.workerNodes[workerNodeKey].usage.runTime?.median ?? 0
 160       : this.pool.workerNodes[workerNodeKey].usage.runTime?.average ?? 0
 161   }
 162
 163   /**
 164    * Gets the worker task wait time.
 165    * If the task statistics require the average wait time, the average wait time is returned.
 166    * If the task statistics require the median wait time, the median wait time is returned.
 167    *
 168    * @param workerNodeKey - The worker node key.
 169    * @returns The worker task wait time.
 170    */
 171   protected getWorkerTaskWaitTime (workerNodeKey: number): number {
 172     return this.taskStatisticsRequirements.waitTime.median
 173       ? this.pool.workerNodes[workerNodeKey].usage.waitTime?.median ?? 0
 174       : this.pool.workerNodes[workerNodeKey].usage.waitTime?.average ?? 0
 175   }
 176
 177   /**
 178    * Gets the worker task ELU.
 179    * If the task statistics require the average ELU, the average ELU is returned.
 180    * If the task statistics require the median ELU, the median ELU is returned.
 181    *
 182    * @param workerNodeKey - The worker node key.
 183    * @returns The worker task ELU.
 184    */
 185   protected getWorkerTaskElu (workerNodeKey: number): number {
 186     return this.taskStatisticsRequirements.elu.median
 187       ? this.pool.workerNodes[workerNodeKey].usage.elu.active?.median ?? 0
 188       : this.pool.workerNodes[workerNodeKey].usage.elu.active?.average ?? 0
 189   }
 190
 191   protected computeDefaultWorkerWeight (): number {
 192     let cpusCycleTimeWeight = 0
 193     for (const cpu of cpus()) {
 194       // CPU estimated cycle time
 195       const numberOfDigits = cpu.speed.toString().length - 1
 196       const cpuCycleTime = 1 / (cpu.speed / Math.pow(10, numberOfDigits))
 197       cpusCycleTimeWeight += cpuCycleTime * Math.pow(10, numberOfDigits)
 198     }
 199     return Math.round(cpusCycleTimeWeight / cpus().length)
 200   }
 201
 202   // /**
 203   //  * Finds the first free worker node key based on the number of tasks the worker has applied.
 204   //  *
 205   //  * If a worker is found with `0` executing tasks, it is detected as free and its worker node key is returned.
 206   //  *
 207   //  * If no free worker is found, `-1` is returned.
 208   //  *
 209   //  * @returns A worker node key if there is one, `-1` otherwise.
 210   //  */
 211   // private findFirstFreeWorkerNodeKey (): number {
 212   //   return this.pool.workerNodes.findIndex(workerNode => {
 213   //     return workerNode.usage.tasks.executing === 0
 214   //   })
 215   // }
 216
 217   // /**
 218   //  * Finds the last free worker node key based on the number of tasks the worker has applied.
 219   //  *
 220   //  * If a worker is found with `0` executing tasks, it is detected as free and its worker node key is returned.
 221   //  *
 222   //  * If no free worker is found, `-1` is returned.
 223   //  *
 224   //  * @returns A worker node key if there is one, `-1` otherwise.
 225   //  */
 226   // private findLastFreeWorkerNodeKey (): number {
 227   //   // It requires node >= 18.0.0:
 228   //   // return this.pool.workerNodes.findLastIndex(workerNode => {
 229   //   //   return workerNode.usage.tasks.executing === 0
 230   //   // })
 231   //   for (
 232   //     let workerNodeKey = this.pool.workerNodes.length - 1;
 233   //     workerNodeKey >= 0;
 234   //     workerNodeKey--
 235   //   ) {
 236   //     if (this.pool.workerNodes[workerNodeKey].usage.tasks.executing === 0) {
 237   //       return workerNodeKey
 238   //     }
 239   //   }
 240   //   return -1
 241   // }
 242 }