1 import { cpus
} from
'node:os'
3 DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS
,
4 DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
6 import type { IPool
} from
'../pool'
7 import type { IWorker
} from
'../worker'
10 MeasurementStatisticsRequirements
,
12 TaskStatisticsRequirements
,
13 WorkerChoiceStrategyOptions
14 } from
'./selection-strategies-types'
17 * Worker choice strategy abstract base class.
19 * @typeParam Worker - Type of worker which manages the strategy.
20 * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
21 * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
23 export abstract class AbstractWorkerChoiceStrategy
<
24 Worker
extends IWorker
,
27 > implements IWorkerChoiceStrategy
{
29 * The next worker node key.
31 protected nextWorkerNodeKey
: number | undefined = 0
34 * The previous worker node key.
36 protected previousWorkerNodeKey
: number = 0
39 public readonly strategyPolicy
: StrategyPolicy
= {
40 dynamicWorkerUsage
: false,
41 dynamicWorkerReady
: true
45 public readonly taskStatisticsRequirements
: TaskStatisticsRequirements
= {
46 runTime
: DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS
,
47 waitTime
: DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS
,
48 elu
: DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS
52 * Constructs a worker choice strategy bound to the pool.
54 * @param pool - The pool instance.
55 * @param opts - The worker choice strategy options.
58 protected readonly pool
: IPool
<Worker
, Data
, Response
>,
59 protected opts
: WorkerChoiceStrategyOptions
= DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
61 this.opts
= { ...DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
, ...opts
}
62 this.choose
= this.choose
.bind(this)
65 protected setTaskStatisticsRequirements (
66 opts
: WorkerChoiceStrategyOptions
68 this.toggleMedianMeasurementStatisticsRequirements(
69 this.taskStatisticsRequirements
.runTime
,
70 opts
.runTime
?.median
as boolean
72 this.toggleMedianMeasurementStatisticsRequirements(
73 this.taskStatisticsRequirements
.waitTime
,
74 opts
.waitTime
?.median
as boolean
76 this.toggleMedianMeasurementStatisticsRequirements(
77 this.taskStatisticsRequirements
.elu
,
78 opts
.elu
?.median
as boolean
82 private toggleMedianMeasurementStatisticsRequirements (
83 measurementStatisticsRequirements
: MeasurementStatisticsRequirements
,
86 if (measurementStatisticsRequirements
.average
&& toggleMedian
) {
87 measurementStatisticsRequirements
.average
= false
88 measurementStatisticsRequirements
.median
= toggleMedian
90 if (measurementStatisticsRequirements
.median
&& !toggleMedian
) {
91 measurementStatisticsRequirements
.average
= true
92 measurementStatisticsRequirements
.median
= toggleMedian
96 protected resetWorkerNodeKeyProperties (): void {
97 this.nextWorkerNodeKey
= 0
98 this.previousWorkerNodeKey
= 0
102 public abstract reset (): boolean
105 public abstract update (workerNodeKey
: number): boolean
108 public abstract choose (): number | undefined
111 public abstract remove (workerNodeKey
: number): boolean
114 public setOptions (opts
: WorkerChoiceStrategyOptions
): void {
115 this.opts
= { ...DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
, ...opts
}
116 this.setTaskStatisticsRequirements(this.opts
)
120 * Whether the worker node is ready or not.
122 * @param workerNodeKey - The worker node key.
123 * @returns Whether the worker node is ready or not.
125 private isWorkerNodeReady (workerNodeKey
: number): boolean {
126 return this.pool
.workerNodes
[workerNodeKey
].info
.ready
130 * Whether the worker node has back pressure or not (i.e. its tasks queue is full).
132 * @param workerNodeKey - The worker node key.
133 * @returns `true` if the worker node has back pressure, `false` otherwise.
135 private hasWorkerNodeBackPressure (workerNodeKey
: number): boolean {
136 return this.pool
.hasWorkerNodeBackPressure(workerNodeKey
)
140 * Whether the worker node is eligible or not.
141 * A worker node is eligible if it is ready and does not have back pressure.
143 * @param workerNodeKey - The worker node key.
144 * @returns `true` if the worker node is eligible, `false` otherwise.
145 * @see {@link isWorkerNodeReady}
146 * @see {@link hasWorkerNodeBackPressure}
148 protected isWorkerNodeEligible (workerNodeKey
: number): boolean {
150 this.isWorkerNodeReady(workerNodeKey
) &&
151 !this.hasWorkerNodeBackPressure(workerNodeKey
)
156 * Gets the worker task runtime.
157 * If the task statistics require the average runtime, the average runtime is returned.
158 * If the task statistics require the median runtime , the median runtime is returned.
160 * @param workerNodeKey - The worker node key.
161 * @returns The worker task runtime.
163 protected getWorkerTaskRunTime (workerNodeKey
: number): number {
164 return this.taskStatisticsRequirements
.runTime
.median
165 ? this.pool
.workerNodes
[workerNodeKey
].usage
.runTime
?.median
?? 0
166 : this.pool
.workerNodes
[workerNodeKey
].usage
.runTime
?.average
?? 0
170 * Gets the worker task wait time.
171 * If the task statistics require the average wait time, the average wait time is returned.
172 * If the task statistics require the median wait time, the median wait time is returned.
174 * @param workerNodeKey - The worker node key.
175 * @returns The worker task wait time.
177 protected getWorkerTaskWaitTime (workerNodeKey
: number): number {
178 return this.taskStatisticsRequirements
.waitTime
.median
179 ? this.pool
.workerNodes
[workerNodeKey
].usage
.waitTime
?.median
?? 0
180 : this.pool
.workerNodes
[workerNodeKey
].usage
.waitTime
?.average
?? 0
184 * Gets the worker task ELU.
185 * If the task statistics require the average ELU, the average ELU is returned.
186 * If the task statistics require the median ELU, the median ELU is returned.
188 * @param workerNodeKey - The worker node key.
189 * @returns The worker task ELU.
191 protected getWorkerTaskElu (workerNodeKey
: number): number {
192 return this.taskStatisticsRequirements
.elu
.median
193 ? this.pool
.workerNodes
[workerNodeKey
].usage
.elu
.active
?.median
?? 0
194 : this.pool
.workerNodes
[workerNodeKey
].usage
.elu
.active
?.average
?? 0
198 * Assign to nextWorkerNodeKey property the chosen worker node key.
200 * @param chosenWorkerNodeKey - The chosen worker node key.
202 protected assignChosenWorkerNodeKey (
203 chosenWorkerNodeKey
: number | undefined
205 if (chosenWorkerNodeKey
!= null) {
206 this.nextWorkerNodeKey
= chosenWorkerNodeKey
208 this.nextWorkerNodeKey
= undefined
212 protected checkNextWorkerNodeEligibility (
213 chosenWorkerNodeKey
: number | undefined
215 if (!this.isWorkerNodeEligible(this.nextWorkerNodeKey
as number)) {
216 this.nextWorkerNodeKey
= undefined
217 this.previousWorkerNodeKey
=
218 chosenWorkerNodeKey
?? this.previousWorkerNodeKey
222 protected computeDefaultWorkerWeight (): number {
223 let cpusCycleTimeWeight
= 0
224 for (const cpu
of cpus()) {
225 // CPU estimated cycle time
226 const numberOfDigits
= cpu
.speed
.toString().length
- 1
227 const cpuCycleTime
= 1 / (cpu
.speed
/ Math.pow(10, numberOfDigits
))
228 cpusCycleTimeWeight
+= cpuCycleTime
* Math.pow(10, numberOfDigits
)
230 return Math.round(cpusCycleTimeWeight
/ cpus().length
)