| 1 | import type { IPool } from '../pool.js' |
| 2 | import type { IWorker } from '../worker.js' |
| 3 | import { AbstractWorkerChoiceStrategy } from './abstract-worker-choice-strategy.js' |
| 4 | import { |
| 5 | type IWorkerChoiceStrategy, |
| 6 | Measurements, |
| 7 | type TaskStatisticsRequirements, |
| 8 | type WorkerChoiceStrategyOptions |
| 9 | } from './selection-strategies-types.js' |
| 10 | |
| 11 | /** |
| 12 | * Selects the next worker with a fair share scheduling algorithm. |
| 13 | * Loosely modeled after the fair queueing algorithm: https://en.wikipedia.org/wiki/Fair_queuing. |
| 14 | * |
| 15 | * @typeParam Worker - Type of worker which manages the strategy. |
| 16 | * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data. |
| 17 | * @typeParam Response - Type of execution response. This can only be structured-cloneable data. |
| 18 | */ |
| 19 | export class FairShareWorkerChoiceStrategy< |
| 20 | Worker extends IWorker, |
| 21 | Data = unknown, |
| 22 | Response = unknown |
| 23 | > |
| 24 | extends AbstractWorkerChoiceStrategy<Worker, Data, Response> |
| 25 | implements IWorkerChoiceStrategy { |
| 26 | /** @inheritDoc */ |
| 27 | public readonly taskStatisticsRequirements: TaskStatisticsRequirements = { |
| 28 | runTime: { |
| 29 | aggregate: true, |
| 30 | average: true, |
| 31 | median: false |
| 32 | }, |
| 33 | waitTime: { |
| 34 | aggregate: true, |
| 35 | average: true, |
| 36 | median: false |
| 37 | }, |
| 38 | elu: { |
| 39 | aggregate: true, |
| 40 | average: true, |
| 41 | median: false |
| 42 | } |
| 43 | } |
| 44 | |
| 45 | /** @inheritDoc */ |
| 46 | public constructor ( |
| 47 | pool: IPool<Worker, Data, Response>, |
| 48 | opts?: WorkerChoiceStrategyOptions |
| 49 | ) { |
| 50 | super(pool, opts) |
| 51 | this.setTaskStatisticsRequirements(this.opts) |
| 52 | } |
| 53 | |
| 54 | /** @inheritDoc */ |
| 55 | public reset (): boolean { |
| 56 | for (const workerNode of this.pool.workerNodes) { |
| 57 | delete workerNode.strategyData?.virtualTaskEndTimestamp |
| 58 | } |
| 59 | return true |
| 60 | } |
| 61 | |
| 62 | /** @inheritDoc */ |
| 63 | public update (workerNodeKey: number): boolean { |
| 64 | this.pool.workerNodes[workerNodeKey].strategyData = { |
| 65 | virtualTaskEndTimestamp: |
| 66 | this.computeWorkerNodeVirtualTaskEndTimestamp(workerNodeKey) |
| 67 | } |
| 68 | return true |
| 69 | } |
| 70 | |
| 71 | /** @inheritDoc */ |
| 72 | public choose (): number | undefined { |
| 73 | this.setPreviousWorkerNodeKey(this.nextWorkerNodeKey) |
| 74 | this.nextWorkerNodeKey = this.fairShareNextWorkerNodeKey() |
| 75 | return this.nextWorkerNodeKey |
| 76 | } |
| 77 | |
| 78 | /** @inheritDoc */ |
| 79 | public remove (): boolean { |
| 80 | return true |
| 81 | } |
| 82 | |
| 83 | private fairShareNextWorkerNodeKey (): number | undefined { |
| 84 | if (this.pool.workerNodes.length === 0) { |
| 85 | return undefined |
| 86 | } |
| 87 | return this.pool.workerNodes.reduce( |
| 88 | (minWorkerNodeKey, workerNode, workerNodeKey, workerNodes) => { |
| 89 | if (workerNode.strategyData?.virtualTaskEndTimestamp == null) { |
| 90 | workerNode.strategyData = { |
| 91 | virtualTaskEndTimestamp: |
| 92 | this.computeWorkerNodeVirtualTaskEndTimestamp(workerNodeKey) |
| 93 | } |
| 94 | } |
| 95 | return this.isWorkerNodeReady(workerNodeKey) && |
| 96 | // eslint-disable-next-line @typescript-eslint/no-non-null-assertion |
| 97 | workerNode.strategyData.virtualTaskEndTimestamp! < |
| 98 | // eslint-disable-next-line @typescript-eslint/no-non-null-assertion |
| 99 | workerNodes[minWorkerNodeKey].strategyData!.virtualTaskEndTimestamp! |
| 100 | ? workerNodeKey |
| 101 | : minWorkerNodeKey |
| 102 | }, |
| 103 | 0 |
| 104 | ) |
| 105 | } |
| 106 | |
| 107 | /** |
| 108 | * Computes the worker node key virtual task end timestamp. |
| 109 | * |
| 110 | * @param workerNodeKey - The worker node key. |
| 111 | * @returns The worker node key virtual task end timestamp. |
| 112 | */ |
| 113 | private computeWorkerNodeVirtualTaskEndTimestamp ( |
| 114 | workerNodeKey: number |
| 115 | ): number { |
| 116 | return this.getWorkerNodeVirtualTaskEndTimestamp( |
| 117 | workerNodeKey, |
| 118 | this.getWorkerNodeVirtualTaskStartTimestamp(workerNodeKey) |
| 119 | ) |
| 120 | } |
| 121 | |
| 122 | private getWorkerNodeVirtualTaskEndTimestamp ( |
| 123 | workerNodeKey: number, |
| 124 | workerNodeVirtualTaskStartTimestamp: number |
| 125 | ): number { |
| 126 | const workerNodeTaskExecutionTime = |
| 127 | this.getWorkerNodeTaskWaitTime(workerNodeKey) + |
| 128 | // eslint-disable-next-line @typescript-eslint/no-non-null-assertion |
| 129 | (this.opts!.measurement === Measurements.elu |
| 130 | ? this.getWorkerNodeTaskElu(workerNodeKey) |
| 131 | : this.getWorkerNodeTaskRunTime(workerNodeKey)) |
| 132 | return workerNodeVirtualTaskStartTimestamp + workerNodeTaskExecutionTime |
| 133 | } |
| 134 | |
| 135 | private getWorkerNodeVirtualTaskStartTimestamp ( |
| 136 | workerNodeKey: number |
| 137 | ): number { |
| 138 | const virtualTaskEndTimestamp = |
| 139 | this.pool.workerNodes[workerNodeKey]?.strategyData |
| 140 | ?.virtualTaskEndTimestamp |
| 141 | const now = performance.now() |
| 142 | return now < (virtualTaskEndTimestamp ?? -Infinity) |
| 143 | ? // eslint-disable-next-line @typescript-eslint/no-non-null-assertion |
| 144 | virtualTaskEndTimestamp! |
| 145 | : now |
| 146 | } |
| 147 | } |