feat: continuous task stealing

[poolifier.git] / src / pools / worker-node.ts

diff --git a/src/pools/worker-node.ts b/src/pools/worker-node.ts
index b539cabd9af018bd71c8c8e27eba63eab755333a..e28372efa1b3c73cf9c8904d6077f87fed1dd553 100644 (file)
--- a/src/pools/worker-node.ts
+++ b/src/pools/worker-node.ts
@@ -1,7 +1,12 @@
 import { MessageChannel } from 'node:worker_threads'
 import { CircularArray } from '../circular-array'
 import type { Task } from '../utility-types'
-import { DEFAULT_TASK_NAME } from '../utils'
+import {
+  DEFAULT_TASK_NAME,
+  EMPTY_FUNCTION,
+  exponentialDelay,
+  sleep
+} from '../utils'
 import { Deque } from '../deque'
 import {
   type IWorker,
@@ -32,8 +37,11 @@ implements IWorkerNode<Worker, Data> {
   public tasksQueueBackPressureSize: number
   /** @inheritdoc */
   public onBackPressure?: (workerId: number) => void
+  /** @inheritdoc */
+  public onEmptyQueue?: (workerId: number) => void
   private readonly taskFunctionsUsage: Map<string, WorkerUsage>
   private readonly tasksQueue: Deque<Task<Data>>
+  private onEmptyQueueCount: number
 
   /**
    * Constructs a new worker node.
@@ -74,6 +82,7 @@ implements IWorkerNode<Worker, Data> {
     this.taskFunctionsUsage = new Map<string, WorkerUsage>()
     this.tasksQueue = new Deque<Task<Data>>()
     this.tasksQueueBackPressureSize = tasksQueueBackPressureSize
+    this.onEmptyQueueCount = 0
   }
 
   /** @inheritdoc */
@@ -81,20 +90,11 @@ implements IWorkerNode<Worker, Data> {
     return this.tasksQueue.size
   }
 
-  /**
-   * Tasks queue maximum size.
-   *
-   * @returns The tasks queue maximum size.
-   */
-  private tasksQueueMaxSize (): number {
-    return this.tasksQueue.maxSize
-  }
-
   /** @inheritdoc */
   public enqueueTask (task: Task<Data>): number {
     const tasksQueueSize = this.tasksQueue.push(task)
     if (this.onBackPressure != null && this.hasBackPressure()) {
-      this.once(this.onBackPressure)(this.info.id as number)
+      this.onBackPressure(this.info.id as number)
     }
     return tasksQueueSize
   }
@@ -103,19 +103,27 @@ implements IWorkerNode<Worker, Data> {
   public unshiftTask (task: Task<Data>): number {
     const tasksQueueSize = this.tasksQueue.unshift(task)
     if (this.onBackPressure != null && this.hasBackPressure()) {
-      this.once(this.onBackPressure)(this.info.id as number)
+      this.onBackPressure(this.info.id as number)
     }
     return tasksQueueSize
   }
 
   /** @inheritdoc */
   public dequeueTask (): Task<Data> | undefined {
-    return this.tasksQueue.shift()
+    const task = this.tasksQueue.shift()
+    if (this.onEmptyQueue != null && this.tasksQueue.size === 0) {
+      this.startOnEmptyQueue().catch(EMPTY_FUNCTION)
+    }
+    return task
   }
 
   /** @inheritdoc */
   public popTask (): Task<Data> | undefined {
-    return this.tasksQueue.pop()
+    const task = this.tasksQueue.pop()
+    if (this.onEmptyQueue != null && this.tasksQueue.size === 0) {
+      this.startOnEmptyQueue().catch(EMPTY_FUNCTION)
+    }
+    return task
   }
 
   /** @inheritdoc */
@@ -169,6 +177,19 @@ implements IWorkerNode<Worker, Data> {
     return this.taskFunctionsUsage.get(name)
   }
 
+  private async startOnEmptyQueue (): Promise<void> {
+    if (this.onEmptyQueue != null) {
+      if (this.tasksQueue.size > 0) {
+        this.onEmptyQueueCount = 0
+        return
+      }
+      this.onEmptyQueue(this.info.id as number)
+      ++this.onEmptyQueueCount
+      await sleep(exponentialDelay(this.onEmptyQueueCount))
+      await this.startOnEmptyQueue()
+    }
+  }
+
   private initWorkerInfo (worker: Worker, workerType: WorkerType): WorkerInfo {
     return {
       id: this.getWorkerId(worker, workerType),
@@ -180,10 +201,10 @@ implements IWorkerNode<Worker, Data> {
 
   private initWorkerUsage (): WorkerUsage {
     const getTasksQueueSize = (): number => {
-      return this.tasksQueueSize()
+      return this.tasksQueue.size
     }
     const getTasksQueueMaxSize = (): number => {
-      return this.tasksQueueMaxSize()
+      return this.tasksQueue.maxSize
     }
     return {
       tasks: {
@@ -195,6 +216,7 @@ implements IWorkerNode<Worker, Data> {
         get maxQueued (): number {
           return getTasksQueueMaxSize()
         },
+        stolen: 0,
         failed: 0
       },
       runTime: {
@@ -235,6 +257,7 @@ implements IWorkerNode<Worker, Data> {
         get queued (): number {
           return getTaskFunctionQueueSize()
         },
+        stolen: 0,
         failed: 0
       },
       runTime: {
@@ -271,25 +294,4 @@ implements IWorkerNode<Worker, Data> {
       return worker.id
     }
   }
-
-  /**
-   * Executes a function once at a time.
-   */
-
-  private once (
-    // eslint-disable-next-line @typescript-eslint/no-explicit-any
-    fn: (...args: any[]) => void,
-    context = this
-    // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  ): (...args: any[]) => void {
-    let called = false
-    // eslint-disable-next-line @typescript-eslint/no-explicit-any
-    return function (...args: any[]): void {
-      if (!called) {
-        called = true
-        fn.apply(context, args)
-        called = false
-      }
-    }
-  }
 }