diff --git a/src/concurrent/qtconcurrentiteratekernel.cpp b/src/concurrent/qtconcurrentiteratekernel.cpp
index 45b54ecfdc..430ae89c85 100644
--- a/src/concurrent/qtconcurrentiteratekernel.cpp
+++ b/src/concurrent/qtconcurrentiteratekernel.cpp
@@ -102,8 +102,8 @@ namespace QtConcurrent {
 /*! \internal
 
 */
-BlockSizeManager::BlockSizeManager(int iterationCount)
-    : maxBlockSize(iterationCount / (QThreadPool::globalInstance()->maxThreadCount() * 2)),
+BlockSizeManager::BlockSizeManager(QThreadPool *pool, int iterationCount)
+    : maxBlockSize(iterationCount / (pool->maxThreadCount() * 2)),
       beforeUser(0), afterUser(0),
       m_blockSize(1)
 { }
diff --git a/src/concurrent/qtconcurrentiteratekernel.h b/src/concurrent/qtconcurrentiteratekernel.h
index 6ea96f5097..a8decf5cf8 100644
--- a/src/concurrent/qtconcurrentiteratekernel.h
+++ b/src/concurrent/qtconcurrentiteratekernel.h
@@ -67,7 +67,7 @@ namespace QtConcurrent {
 class Q_CONCURRENT_EXPORT BlockSizeManager
 {
 public:
-    explicit BlockSizeManager(int iterationCount);
+    explicit BlockSizeManager(QThreadPool *pool, int iterationCount);
 
     void timeBeforeUser();
     void timeAfterUser();
@@ -198,7 +198,7 @@ public:
 
     ThreadFunctionResult forThreadFunction()
     {
-        BlockSizeManager blockSizeManager(iterationCount);
+        BlockSizeManager blockSizeManager(ThreadEngineBase::threadPool, iterationCount);
         ResultReporter<T> resultReporter(this);
 
         for(;;) {