| 1 | import { cpus } from 'node:os' |
| 2 | import type { IWorker } from '../worker' |
| 3 | import { AbstractWorkerChoiceStrategy } from './abstract-worker-choice-strategy' |
| 4 | import type { |
| 5 | IWorkerChoiceStrategy, |
| 6 | RequiredStatistics, |
| 7 | WorkerChoiceStrategyOptions |
| 8 | } from './selection-strategies-types' |
| 9 | import type { IPool } from '../pool' |
| 10 | |
| 11 | /** |
| 12 | * Virtual task runtime. |
| 13 | */ |
| 14 | interface TaskRunTime { |
| 15 | weight: number |
| 16 | runTime: number |
| 17 | } |
| 18 | |
| 19 | /** |
| 20 | * Selects the next worker with a weighted round robin scheduling algorithm. |
| 21 | * Loosely modeled after the weighted round robin queueing algorithm: https://en.wikipedia.org/wiki/Weighted_round_robin. |
| 22 | * |
| 23 | * @typeParam Worker - Type of worker which manages the strategy. |
| 24 | * @typeParam Data - Type of data sent to the worker. This can only be serializable data. |
| 25 | * @typeParam Response - Type of execution response. This can only be serializable data. |
| 26 | */ |
| 27 | export class WeightedRoundRobinWorkerChoiceStrategy< |
| 28 | Worker extends IWorker, |
| 29 | Data = unknown, |
| 30 | Response = unknown |
| 31 | > |
| 32 | extends AbstractWorkerChoiceStrategy<Worker, Data, Response> |
| 33 | implements IWorkerChoiceStrategy { |
| 34 | /** @inheritDoc */ |
| 35 | public readonly requiredStatistics: RequiredStatistics = { |
| 36 | runTime: true, |
| 37 | avgRunTime: true, |
| 38 | medRunTime: false |
| 39 | } |
| 40 | |
| 41 | /** |
| 42 | * Worker node id where the current task will be submitted. |
| 43 | */ |
| 44 | private currentWorkerNodeId: number = 0 |
| 45 | /** |
| 46 | * Default worker weight. |
| 47 | */ |
| 48 | private readonly defaultWorkerWeight: number |
| 49 | /** |
| 50 | * Workers' virtual task runtime. |
| 51 | */ |
| 52 | private readonly workersTaskRunTime: Map<number, TaskRunTime> = new Map< |
| 53 | number, |
| 54 | TaskRunTime |
| 55 | >() |
| 56 | |
| 57 | /** |
| 58 | * Constructs a worker choice strategy that selects with a weighted round robin scheduling algorithm. |
| 59 | * |
| 60 | * @param pool - The pool instance. |
| 61 | * @param opts - The worker choice strategy options. |
| 62 | */ |
| 63 | public constructor ( |
| 64 | pool: IPool<Worker, Data, Response>, |
| 65 | opts?: WorkerChoiceStrategyOptions |
| 66 | ) { |
| 67 | super(pool, opts) |
| 68 | this.defaultWorkerWeight = this.computeWorkerWeight() |
| 69 | this.initWorkersTaskRunTime() |
| 70 | } |
| 71 | |
| 72 | /** @inheritDoc */ |
| 73 | public reset (): boolean { |
| 74 | this.currentWorkerNodeId = 0 |
| 75 | this.workersTaskRunTime.clear() |
| 76 | this.initWorkersTaskRunTime() |
| 77 | return true |
| 78 | } |
| 79 | |
| 80 | /** @inheritDoc */ |
| 81 | public choose (): number { |
| 82 | const chosenWorkerNodeKey = this.currentWorkerNodeId |
| 83 | if ( |
| 84 | this.isDynamicPool && |
| 85 | !this.workersTaskRunTime.has(chosenWorkerNodeKey) |
| 86 | ) { |
| 87 | this.initWorkerTaskRunTime(chosenWorkerNodeKey) |
| 88 | } |
| 89 | const workerTaskRunTime = |
| 90 | this.workersTaskRunTime.get(chosenWorkerNodeKey)?.runTime ?? 0 |
| 91 | const workerTaskWeight = |
| 92 | this.workersTaskRunTime.get(chosenWorkerNodeKey)?.weight ?? |
| 93 | this.defaultWorkerWeight |
| 94 | if (workerTaskRunTime < workerTaskWeight) { |
| 95 | this.setWorkerTaskRunTime( |
| 96 | chosenWorkerNodeKey, |
| 97 | workerTaskWeight, |
| 98 | workerTaskRunTime + |
| 99 | (this.getWorkerVirtualTaskRunTime(chosenWorkerNodeKey) ?? 0) |
| 100 | ) |
| 101 | } else { |
| 102 | this.currentWorkerNodeId = |
| 103 | this.currentWorkerNodeId === this.pool.workerNodes.length - 1 |
| 104 | ? 0 |
| 105 | : this.currentWorkerNodeId + 1 |
| 106 | this.setWorkerTaskRunTime(this.currentWorkerNodeId, workerTaskWeight, 0) |
| 107 | } |
| 108 | return chosenWorkerNodeKey |
| 109 | } |
| 110 | |
| 111 | /** @inheritDoc */ |
| 112 | public remove (workerNodeKey: number): boolean { |
| 113 | if (this.currentWorkerNodeId === workerNodeKey) { |
| 114 | if (this.pool.workerNodes.length === 0) { |
| 115 | this.currentWorkerNodeId = 0 |
| 116 | } else { |
| 117 | this.currentWorkerNodeId = |
| 118 | this.currentWorkerNodeId > this.pool.workerNodes.length - 1 |
| 119 | ? this.pool.workerNodes.length - 1 |
| 120 | : this.currentWorkerNodeId |
| 121 | } |
| 122 | } |
| 123 | const deleted = this.workersTaskRunTime.delete(workerNodeKey) |
| 124 | for (const [key, value] of this.workersTaskRunTime) { |
| 125 | if (key > workerNodeKey) { |
| 126 | this.workersTaskRunTime.set(key - 1, value) |
| 127 | } |
| 128 | } |
| 129 | return deleted |
| 130 | } |
| 131 | |
| 132 | private initWorkersTaskRunTime (): void { |
| 133 | for (const [index] of this.pool.workerNodes.entries()) { |
| 134 | this.initWorkerTaskRunTime(index) |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | private initWorkerTaskRunTime (workerNodeKey: number): void { |
| 139 | this.setWorkerTaskRunTime(workerNodeKey, this.defaultWorkerWeight, 0) |
| 140 | } |
| 141 | |
| 142 | private setWorkerTaskRunTime ( |
| 143 | workerNodeKey: number, |
| 144 | weight: number, |
| 145 | runTime: number |
| 146 | ): void { |
| 147 | this.workersTaskRunTime.set(workerNodeKey, { |
| 148 | weight, |
| 149 | runTime |
| 150 | }) |
| 151 | } |
| 152 | |
| 153 | private getWorkerVirtualTaskRunTime (workerNodeKey: number): number { |
| 154 | return this.requiredStatistics.medRunTime |
| 155 | ? this.pool.workerNodes[workerNodeKey].tasksUsage.medRunTime |
| 156 | : this.pool.workerNodes[workerNodeKey].tasksUsage.avgRunTime |
| 157 | } |
| 158 | |
| 159 | private computeWorkerWeight (): number { |
| 160 | let cpusCycleTimeWeight = 0 |
| 161 | for (const cpu of cpus()) { |
| 162 | // CPU estimated cycle time |
| 163 | const numberOfDigits = cpu.speed.toString().length - 1 |
| 164 | const cpuCycleTime = 1 / (cpu.speed / Math.pow(10, numberOfDigits)) |
| 165 | cpusCycleTimeWeight += cpuCycleTime * Math.pow(10, numberOfDigits) |
| 166 | } |
| 167 | return Math.round(cpusCycleTimeWeight / cpus().length) |
| 168 | } |
| 169 | } |