From f4ff1ce25e8ec840112e33e306e492b063738e6d Mon Sep 17 00:00:00 2001
From: =?utf8?q?J=C3=A9r=C3=B4me=20Benoit?= <jerome.benoit@sap.com>
Date: Sun, 2 Apr 2023 16:30:02 +0200
Subject: [PATCH] perf: take into account the number of run tasks in LRU worker
 choice strategy
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
Content-Transfer-Encoding: 8bit

Signed-off-by: Jérôme Benoit <jerome.benoit@sap.com>
---
 CHANGELOG.md                                       |  1 +
 src/pools/abstract-pool.ts                         | 11 +++++++----
 src/pools/pool-internal.ts                         | 10 +++++++++-
 .../less-recently-used-worker-choice-strategy.ts   | 14 +++++++-------
 4 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b21ed16f..84e8ac47 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Optimize worker storage in pool.
 - Optimize worker alive status check.
+- Optimize `LESS_RECENTLY_USED` worker choice strategy.
 
 ### Fixed
 
diff --git a/src/pools/abstract-pool.ts b/src/pools/abstract-pool.ts
index 363db0e3..b3ebc194 100644
--- a/src/pools/abstract-pool.ts
+++ b/src/pools/abstract-pool.ts
@@ -165,14 +165,17 @@ export abstract class AbstractPool<
 
   /** {@inheritDoc} */
   public getWorkerRunningTasks (worker: Worker): number | undefined {
-    return this.workers.get(this.getWorkerKey(worker) as number)?.tasksUsage
-      ?.running
+    return this.getWorkerTasksUsage(worker)?.running
+  }
+
+  /** {@inheritDoc} */
+  public getWorkerRunTasks (worker: Worker): number | undefined {
+    return this.getWorkerTasksUsage(worker)?.run
   }
 
   /** {@inheritDoc} */
   public getWorkerAverageTasksRunTime (worker: Worker): number | undefined {
-    return this.workers.get(this.getWorkerKey(worker) as number)?.tasksUsage
-      ?.avgRunTime
+    return this.getWorkerTasksUsage(worker)?.avgRunTime
   }
 
   /** {@inheritDoc} */
diff --git a/src/pools/pool-internal.ts b/src/pools/pool-internal.ts
index 97e5d5d2..9656175f 100644
--- a/src/pools/pool-internal.ts
+++ b/src/pools/pool-internal.ts
@@ -42,7 +42,7 @@ export interface IPoolInternal<
   Response = unknown
 > extends IPool<Data, Response> {
   /**
-   * Map of workers.
+   * Pool workers map.
    */
   readonly workers: Map<number, WorkerType<Worker>>
 
@@ -84,6 +84,14 @@ export interface IPoolInternal<
    */
   getWorkerRunningTasks: (worker: Worker) => number | undefined
 
+  /**
+   * Gets worker run tasks.
+   *
+   * @param worker - The worker.
+   * @returns The number of tasks run on the worker.
+   */
+  getWorkerRunTasks: (worker: Worker) => number | undefined
+
   /**
    * Gets worker average tasks runtime.
    *
diff --git a/src/pools/selection-strategies/less-recently-used-worker-choice-strategy.ts b/src/pools/selection-strategies/less-recently-used-worker-choice-strategy.ts
index 467cf2c6..9e582a6e 100644
--- a/src/pools/selection-strategies/less-recently-used-worker-choice-strategy.ts
+++ b/src/pools/selection-strategies/less-recently-used-worker-choice-strategy.ts
@@ -20,19 +20,19 @@ export class LessRecentlyUsedWorkerChoiceStrategy<
 
   /** {@inheritDoc} */
   public choose (): Worker {
-    let minNumberOfRunningTasks = Infinity
+    let minNumberOfTasks = Infinity
     // A worker is always found because it picks the one with fewer tasks
     let lessRecentlyUsedWorker!: Worker
     for (const value of this.pool.workers.values()) {
       const worker = value.worker
-      const workerRunningTasks = this.pool.getWorkerRunningTasks(
-        worker
-      ) as number
-      if (!this.isDynamicPool && workerRunningTasks === 0) {
+      const workerTasks =
+        (this.pool.getWorkerRunTasks(worker) as number) +
+        (this.pool.getWorkerRunningTasks(worker) as number)
+      if (!this.isDynamicPool && workerTasks === 0) {
         return worker
-      } else if (workerRunningTasks < minNumberOfRunningTasks) {
+      } else if (workerTasks < minNumberOfTasks) {
+        minNumberOfTasks = workerTasks
         lessRecentlyUsedWorker = worker
-        minNumberOfRunningTasks = workerRunningTasks
       }
     }
     return lessRecentlyUsedWorker
-- 
2.34.1