From bf7ac6f5e0ac0dd085a9c10f38619a3e0d479006 Mon Sep 17 00:00:00 2001
From: Tomas Votruba <tomas.vot@gmail.com>
Date: Fri, 9 Oct 2026 09:14:59 +0200
Subject: [PATCH] Respect cgroup/CFS CPU quota in parallel worker count

---
 src/Parallel/CpuCoreCountProvider.php | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/src/Parallel/CpuCoreCountProvider.php b/src/Parallel/CpuCoreCountProvider.php
index c23aebf3dde..7e56c815678 100644
--- a/src/Parallel/CpuCoreCountProvider.php
+++ b/src/Parallel/CpuCoreCountProvider.php
@@ -5,19 +5,15 @@
 namespace Rector\Parallel;
 
 use Fidry\CpuCoreCounter\CpuCoreCounter;
-use Fidry\CpuCoreCounter\NumberOfCpuCoreNotFound;
 
 final class CpuCoreCountProvider
 {
-    private const int DEFAULT_CORE_COUNT = 2;
-
     public function provide(): int
     {
-        try {
-            return new CpuCoreCounter()
-                ->getCount();
-        } catch (NumberOfCpuCoreNotFound) {
-            return self::DEFAULT_CORE_COUNT;
-        }
+        // getAvailableForParallelisation() respects cgroup/CFS quota (docker --cpus, KUBERNETES_CPU_LIMIT),
+        // unlike getCount() which reports host cores and overcommits workers in containers
+        return new CpuCoreCounter()
+            ->getAvailableForParallelisation()
+            ->availableCpus;
     }
 }