perf: optimize task(s) stealing implementation

[poolifier.git] / src / pools / selection-strategies / fair-share-worker-choice-strategy.ts

diff --git a/src/pools/selection-strategies/fair-share-worker-choice-strategy.ts b/src/pools/selection-strategies/fair-share-worker-choice-strategy.ts
index 0ae939949b1c115918db6bb1f33dfab2e253191a..a337278ba9ce75a074c1b32d751d8f928ec86496 100644 (file)
--- a/src/pools/selection-strategies/fair-share-worker-choice-strategy.ts
+++ b/src/pools/selection-strategies/fair-share-worker-choice-strategy.ts
@@ -1,11 +1,15 @@
-import { DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS } from '../../utils'
+import {
+  DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS,
+  DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
+} from '../../utils'
 import type { IPool } from '../pool'
-import type { IWorker } from '../worker'
+import type { IWorker, StrategyData } from '../worker'
 import { AbstractWorkerChoiceStrategy } from './abstract-worker-choice-strategy'
-import type {
-  IWorkerChoiceStrategy,
-  RequiredStatistics,
-  WorkerChoiceStrategyOptions
+import {
+  type IWorkerChoiceStrategy,
+  Measurements,
+  type TaskStatisticsRequirements,
+  type WorkerChoiceStrategyOptions
 } from './selection-strategies-types'
 
 /**
@@ -13,8 +17,8 @@ import type {
  * Loosely modeled after the fair queueing algorithm: https://en.wikipedia.org/wiki/Fair_queuing.
  *
  * @typeParam Worker - Type of worker which manages the strategy.
- * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
- * @typeParam Response - Type of execution response. This can only be serializable data.
+ * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
+ * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
  */
 export class FairShareWorkerChoiceStrategy<
     Worker extends IWorker,
@@ -24,89 +28,112 @@ export class FairShareWorkerChoiceStrategy<
   extends AbstractWorkerChoiceStrategy<Worker, Data, Response>
   implements IWorkerChoiceStrategy {
   /** @inheritDoc */
-  public readonly requiredStatistics: RequiredStatistics = {
-    runTime: true,
-    avgRunTime: true,
-    medRunTime: false
+  public readonly taskStatisticsRequirements: TaskStatisticsRequirements = {
+    runTime: {
+      aggregate: true,
+      average: true,
+      median: false
+    },
+    waitTime: DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS,
+    elu: {
+      aggregate: true,
+      average: true,
+      median: false
+    }
   }
 
-  /**
-   * Workers' virtual task end execution timestamp.
-   */
-  private workersVirtualTaskEndTimestamp: number[] = []
-
   /** @inheritDoc */
   public constructor (
     pool: IPool<Worker, Data, Response>,
     opts: WorkerChoiceStrategyOptions = DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
   ) {
     super(pool, opts)
-    this.setRequiredStatistics(this.opts)
+    this.setTaskStatisticsRequirements(this.opts)
   }
 
   /** @inheritDoc */
   public reset (): boolean {
-    this.workersVirtualTaskEndTimestamp = []
+    for (const workerNode of this.pool.workerNodes) {
+      delete workerNode.strategyData?.virtualTaskEndTimestamp
+    }
     return true
   }
 
   /** @inheritDoc */
   public update (workerNodeKey: number): boolean {
-    this.computeWorkerVirtualTaskEndTimestamp(workerNodeKey)
+    this.pool.workerNodes[workerNodeKey].strategyData = {
+      virtualTaskEndTimestamp:
+        this.computeWorkerNodeVirtualTaskEndTimestamp(workerNodeKey)
+    }
     return true
   }
 
   /** @inheritDoc */
-  public choose (): number {
-    let minWorkerVirtualTaskEndTimestamp = Infinity
-    let chosenWorkerNodeKey!: number
-    for (const [workerNodeKey] of this.pool.workerNodes.entries()) {
-      if (this.workersVirtualTaskEndTimestamp[workerNodeKey] == null) {
-        this.computeWorkerVirtualTaskEndTimestamp(workerNodeKey)
-      }
-      const workerVirtualTaskEndTimestamp =
-        this.workersVirtualTaskEndTimestamp[workerNodeKey]
-      if (workerVirtualTaskEndTimestamp < minWorkerVirtualTaskEndTimestamp) {
-        minWorkerVirtualTaskEndTimestamp = workerVirtualTaskEndTimestamp
-        chosenWorkerNodeKey = workerNodeKey
-      }
-    }
-    return chosenWorkerNodeKey
+  public choose (): number | undefined {
+    this.setPreviousWorkerNodeKey(this.nextWorkerNodeKey)
+    this.nextWorkerNodeKey = this.fairShareNextWorkerNodeKey()
+    return this.nextWorkerNodeKey
   }
 
   /** @inheritDoc */
-  public remove (workerNodeKey: number): boolean {
-    this.workersVirtualTaskEndTimestamp.splice(workerNodeKey, 1)
+  public remove (): boolean {
     return true
   }
 
+  private fairShareNextWorkerNodeKey (): number | undefined {
+    return this.pool.workerNodes.reduce(
+      (minWorkerNodeKey, workerNode, workerNodeKey, workerNodes) => {
+        if (workerNode.strategyData?.virtualTaskEndTimestamp == null) {
+          workerNode.strategyData = {
+            virtualTaskEndTimestamp:
+              this.computeWorkerNodeVirtualTaskEndTimestamp(workerNodeKey)
+          }
+        }
+        return (workerNode.strategyData.virtualTaskEndTimestamp as number) <
+          ((workerNodes[minWorkerNodeKey].strategyData as StrategyData)
+            .virtualTaskEndTimestamp as number)
+          ? workerNodeKey
+          : minWorkerNodeKey
+      },
+      0
+    )
+  }
+
   /**
    * Computes the worker node key virtual task end timestamp.
    *
    * @param workerNodeKey - The worker node key.
+   * @returns The worker node key virtual task end timestamp.
    */
-  private computeWorkerVirtualTaskEndTimestamp (workerNodeKey: number): void {
-    this.workersVirtualTaskEndTimestamp[workerNodeKey] =
-      this.getWorkerVirtualTaskEndTimestamp(
-        workerNodeKey,
-        this.getWorkerVirtualTaskStartTimestamp(workerNodeKey)
-      )
+  private computeWorkerNodeVirtualTaskEndTimestamp (
+    workerNodeKey: number
+  ): number {
+    return this.getWorkerNodeVirtualTaskEndTimestamp(
+      workerNodeKey,
+      this.getWorkerNodeVirtualTaskStartTimestamp(workerNodeKey)
+    )
   }
 
-  private getWorkerVirtualTaskEndTimestamp (
+  private getWorkerNodeVirtualTaskEndTimestamp (
     workerNodeKey: number,
-    workerVirtualTaskStartTimestamp: number
+    workerNodeVirtualTaskStartTimestamp: number
   ): number {
-    const workerVirtualTaskRunTime = this.requiredStatistics.medRunTime
-      ? this.pool.workerNodes[workerNodeKey].tasksUsage.medRunTime
-      : this.pool.workerNodes[workerNodeKey].tasksUsage.avgRunTime
-    return workerVirtualTaskStartTimestamp + workerVirtualTaskRunTime
+    const workerNodeTaskRunTime =
+      this.opts.measurement === Measurements.elu
+        ? this.getWorkerNodeTaskElu(workerNodeKey)
+        : this.getWorkerNodeTaskRunTime(workerNodeKey)
+    return workerNodeVirtualTaskStartTimestamp + workerNodeTaskRunTime
   }
 
-  private getWorkerVirtualTaskStartTimestamp (workerNodeKey: number): number {
-    return Math.max(
-      performance.now(),
-      this.workersVirtualTaskEndTimestamp[workerNodeKey] ?? -Infinity
-    )
+  private getWorkerNodeVirtualTaskStartTimestamp (
+    workerNodeKey: number
+  ): number {
+    const virtualTaskEndTimestamp =
+      this.pool.workerNodes[workerNodeKey]?.strategyData
+        ?.virtualTaskEndTimestamp
+    const now = performance.now()
+    return now < (virtualTaskEndTimestamp ?? -Infinity)
+      ? (virtualTaskEndTimestamp as number)
+      : now
   }
 }