| 1 | import { cpus } from 'node:os' |
| 2 | import type { IWorker } from '../worker' |
| 3 | import type { IPool } from '../pool' |
| 4 | import { DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS } from '../../utils' |
| 5 | import { AbstractWorkerChoiceStrategy } from './abstract-worker-choice-strategy' |
| 6 | import type { |
| 7 | IWorkerChoiceStrategy, |
| 8 | RequiredStatistics, |
| 9 | WorkerChoiceStrategyOptions |
| 10 | } from './selection-strategies-types' |
| 11 | |
| 12 | /** |
| 13 | * Selects the next worker with a weighted round robin scheduling algorithm. |
| 14 | * Loosely modeled after the weighted round robin queueing algorithm: https://en.wikipedia.org/wiki/Weighted_round_robin. |
| 15 | * |
| 16 | * @typeParam Worker - Type of worker which manages the strategy. |
| 17 | * @typeParam Data - Type of data sent to the worker. This can only be serializable data. |
| 18 | * @typeParam Response - Type of execution response. This can only be serializable data. |
| 19 | */ |
| 20 | export class WeightedRoundRobinWorkerChoiceStrategy< |
| 21 | Worker extends IWorker, |
| 22 | Data = unknown, |
| 23 | Response = unknown |
| 24 | > |
| 25 | extends AbstractWorkerChoiceStrategy<Worker, Data, Response> |
| 26 | implements IWorkerChoiceStrategy { |
| 27 | /** @inheritDoc */ |
| 28 | public readonly requiredStatistics: RequiredStatistics = { |
| 29 | runTime: true, |
| 30 | avgRunTime: true, |
| 31 | medRunTime: false |
| 32 | } |
| 33 | |
| 34 | /** |
| 35 | * Worker node id where the current task will be submitted. |
| 36 | */ |
| 37 | private currentWorkerNodeId: number = 0 |
| 38 | /** |
| 39 | * Default worker weight. |
| 40 | */ |
| 41 | private readonly defaultWorkerWeight: number |
| 42 | /** |
| 43 | * Worker virtual task runtime. |
| 44 | */ |
| 45 | private workerVirtualTaskRunTime: number = 0 |
| 46 | |
| 47 | /** @inheritDoc */ |
| 48 | public constructor ( |
| 49 | pool: IPool<Worker, Data, Response>, |
| 50 | opts: WorkerChoiceStrategyOptions = DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS |
| 51 | ) { |
| 52 | super(pool, opts) |
| 53 | this.setRequiredStatistics(this.opts) |
| 54 | this.defaultWorkerWeight = this.computeDefaultWorkerWeight() |
| 55 | } |
| 56 | |
| 57 | /** @inheritDoc */ |
| 58 | public reset (): boolean { |
| 59 | this.currentWorkerNodeId = 0 |
| 60 | this.workerVirtualTaskRunTime = 0 |
| 61 | return true |
| 62 | } |
| 63 | |
| 64 | /** @inheritDoc */ |
| 65 | public update (): boolean { |
| 66 | return true |
| 67 | } |
| 68 | |
| 69 | /** @inheritDoc */ |
| 70 | public choose (): number { |
| 71 | const chosenWorkerNodeKey = this.currentWorkerNodeId |
| 72 | const workerVirtualTaskRunTime = this.workerVirtualTaskRunTime |
| 73 | const workerWeight = |
| 74 | this.opts.weights?.[chosenWorkerNodeKey] ?? this.defaultWorkerWeight |
| 75 | if (workerVirtualTaskRunTime < workerWeight) { |
| 76 | this.workerVirtualTaskRunTime = |
| 77 | workerVirtualTaskRunTime + |
| 78 | this.getWorkerTaskRunTime(chosenWorkerNodeKey) |
| 79 | } else { |
| 80 | this.currentWorkerNodeId = |
| 81 | this.currentWorkerNodeId === this.pool.workerNodes.length - 1 |
| 82 | ? 0 |
| 83 | : this.currentWorkerNodeId + 1 |
| 84 | this.workerVirtualTaskRunTime = 0 |
| 85 | } |
| 86 | return chosenWorkerNodeKey |
| 87 | } |
| 88 | |
| 89 | /** @inheritDoc */ |
| 90 | public remove (workerNodeKey: number): boolean { |
| 91 | if (this.currentWorkerNodeId === workerNodeKey) { |
| 92 | if (this.pool.workerNodes.length === 0) { |
| 93 | this.currentWorkerNodeId = 0 |
| 94 | } else if (this.currentWorkerNodeId > this.pool.workerNodes.length - 1) { |
| 95 | this.currentWorkerNodeId = this.pool.workerNodes.length - 1 |
| 96 | } |
| 97 | this.workerVirtualTaskRunTime = 0 |
| 98 | } |
| 99 | return true |
| 100 | } |
| 101 | |
| 102 | private computeDefaultWorkerWeight (): number { |
| 103 | let cpusCycleTimeWeight = 0 |
| 104 | for (const cpu of cpus()) { |
| 105 | // CPU estimated cycle time |
| 106 | const numberOfDigits = cpu.speed.toString().length - 1 |
| 107 | const cpuCycleTime = 1 / (cpu.speed / Math.pow(10, numberOfDigits)) |
| 108 | cpusCycleTimeWeight += cpuCycleTime * Math.pow(10, numberOfDigits) |
| 109 | } |
| 110 | return Math.round(cpusCycleTimeWeight / cpus().length) |
| 111 | } |
| 112 | } |