Fix deadlock when running with QT3D_MAX_THREAD_COUNT=1

Also remove duplication and make QAspectJobManager::idealThreadCount
the centralized function to retrieve expect maximum number of threads.

Change-Id: Iec8d65d368ac7825ef87e883a987551726603adc
Reviewed-by: Mike Krus <mike.krus@kdab.com>
(cherry picked from commit 9ef97eaee6a1e795f0e5c2af7df29148914fb1b3)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

13 files changed, 34 insertions, 70 deletions

diff --git a/src/core/jobs/calcboundingvolumejob.cpp b/src/core/jobs/calcboundingvolumejob.cpp
index 5e1b3362d..4bad98b16 100644
--- a/src/core/jobs/calcboundingvolumejob.cpp
+++ b/src/core/jobs/calcboundingvolumejob.cpp
@@ -293,7 +293,7 @@ void CalculateBoundingVolumeJob::run()
     });
 
 #if QT_CONFIG(concurrent)
-    if (dirtyEntities.size() > 1 && QThreadPooler::maxThreadCount() > 1) {
+    if (dirtyEntities.size() > 1 && QAspectJobManager::idealThreadCount() > 1) {
         UpdateBoundFunctor functor;
         ReduceUpdateBoundFunctor reduceFunctor;
         m_results = QtConcurrent::blockingMappedReduced<decltype(m_results)>(dirtyEntities, functor, reduceFunctor);
diff --git a/src/core/jobs/qaspectjobmanager.cpp b/src/core/jobs/qaspectjobmanager.cpp
index e99ba4480..e352536cd 100644
--- a/src/core/jobs/qaspectjobmanager.cpp
+++ b/src/core/jobs/qaspectjobmanager.cpp
@@ -115,7 +115,7 @@ int QAspectJobManager::waitForAllJobs()
 
 void QAspectJobManager::waitForPerThreadFunction(JobFunction func, void *arg)
 {
-    const int threadCount = m_threadPooler->maxThreadCount();
+    const int threadCount = QAspectJobManager::idealThreadCount();
     QAtomicInt atomicCount(threadCount);
 
     QList<RunnableInterface *> taskList;
@@ -128,6 +128,27 @@ void QAspectJobManager::waitForPerThreadFunction(JobFunction func, void *arg)
     future.waitForFinished();
 }
 
+
+int QAspectJobManager::idealThreadCount()
+{
+    static int jobCount = 0;
+    if (jobCount)
+        return jobCount;
+
+    const QByteArray maxThreadCount = qgetenv("QT3D_MAX_THREAD_COUNT");
+    if (!maxThreadCount.isEmpty()) {
+        bool conversionOK = false;
+        const int maxThreadCountValue = maxThreadCount.toInt(&conversionOK);
+        if (conversionOK) {
+            jobCount = maxThreadCountValue;
+            return jobCount;
+        }
+    }
+
+    jobCount = QThread::idealThreadCount();
+    return jobCount;
+}
+
 } // namespace Qt3DCore
 
 QT_END_NAMESPACE
diff --git a/src/core/jobs/qaspectjobmanager_p.h b/src/core/jobs/qaspectjobmanager_p.h
index e27c850f3..169302c34 100644
--- a/src/core/jobs/qaspectjobmanager_p.h
+++ b/src/core/jobs/qaspectjobmanager_p.h
@@ -78,6 +78,7 @@ public:
     int waitForAllJobs() override;
 
     void waitForPerThreadFunction(JobFunction func, void *arg) override;
+    static int idealThreadCount();
 
 private:
     QThreadPooler *m_threadPooler;
diff --git a/src/core/jobs/qthreadpooler.cpp b/src/core/jobs/qthreadpooler.cpp
index b4c7a2b05..b2f53b7e7 100644
--- a/src/core/jobs/qthreadpooler.cpp
+++ b/src/core/jobs/qthreadpooler.cpp
@@ -38,6 +38,7 @@
 ****************************************************************************/
 
 #include "qthreadpooler_p.h"
+#include "qaspectjobmanager_p.h"
 #include <QtCore/QDebug>
 
 QT_BEGIN_NAMESPACE
@@ -52,7 +53,7 @@ QThreadPooler::QThreadPooler(QObject *parent)
     , m_threadPool(QThreadPool::globalInstance())
     , m_totalRunJobs(0)
 {
-    m_threadPool->setMaxThreadCount(QThreadPooler::maxThreadCount());
+    m_threadPool->setMaxThreadCount(QAspectJobManager::idealThreadCount());
     // Ensures that threads will never be recycled
     m_threadPool->setExpiryTimeout(-1);
 }
@@ -199,24 +200,6 @@ int QThreadPooler::currentCount() const
     return m_taskCount.loadRelaxed();
 }
 
-int QThreadPooler::maxThreadCount()
-{
-    static int threadCount = 0;
-
-    if (threadCount == 0) {
-        threadCount = QThread::idealThreadCount();
-        const QByteArray maxThreadCount = qgetenv("QT3D_MAX_THREAD_COUNT");
-        if (!maxThreadCount.isEmpty()) {
-            bool conversionOK = false;
-            const int maxThreadCountValue = maxThreadCount.toInt(&conversionOK);
-            if (conversionOK)
-                threadCount = std::min(threadCount, maxThreadCountValue);
-        }
-    }
-
-    return threadCount;
-}
-
 } // namespace Qt3DCore
 
 QT_END_NAMESPACE
diff --git a/src/plugins/renderers/opengl/renderer/renderer.cpp b/src/plugins/renderers/opengl/renderer/renderer.cpp
index ede7e2234..085556a88 100644
--- a/src/plugins/renderers/opengl/renderer/renderer.cpp
+++ b/src/plugins/renderers/opengl/renderer/renderer.cpp
@@ -1862,7 +1862,7 @@ std::vector<Qt3DCore::QAspectJobPtr> Renderer::renderBinJobs()
             m_updatedDisableSubtreeEnablers.push_back(node->peerId());
     }
 
-    int idealThreadCount = QThreadPooler::maxThreadCount();
+    int idealThreadCount = QAspectJobManager::idealThreadCount();
 
     const size_t fgBranchCount = m_frameGraphLeaves.size();
     if (fgBranchCount > 1) {
diff --git a/src/plugins/renderers/opengl/renderer/renderviewbuilder.cpp b/src/plugins/renderers/opengl/renderer/renderviewbuilder.cpp
index 6ba85db9e..d21c205c3 100644
--- a/src/plugins/renderers/opengl/renderer/renderviewbuilder.cpp
+++ b/src/plugins/renderers/opengl/renderer/renderviewbuilder.cpp
@@ -435,26 +435,6 @@ bool RenderViewBuilder::lightCacheNeedsToBeRebuilt() const
     return m_rebuildFlags.testFlag(RebuildFlag::LightCacheRebuild);
 }
 
-int RenderViewBuilder::defaultJobCount()
-{
-    static int jobCount = 0;
-    if (jobCount)
-        return jobCount;
-
-    const QByteArray maxThreadCount = qgetenv("QT3D_MAX_THREAD_COUNT");
-    if (!maxThreadCount.isEmpty()) {
-        bool conversionOK = false;
-        const int maxThreadCountValue = maxThreadCount.toInt(&conversionOK);
-        if (conversionOK) {
-            jobCount = maxThreadCountValue;
-            return jobCount;
-        }
-    }
-
-    jobCount = QThread::idealThreadCount();
-    return jobCount;
-}
-
 int RenderViewBuilder::optimalJobCount() const
 {
     return m_optimalParallelJobCount;
diff --git a/src/plugins/renderers/opengl/renderer/renderviewbuilder_p.h b/src/plugins/renderers/opengl/renderer/renderviewbuilder_p.h
index a2a515d1a..acf4f9892 100644
--- a/src/plugins/renderers/opengl/renderer/renderviewbuilder_p.h
+++ b/src/plugins/renderers/opengl/renderer/renderviewbuilder_p.h
@@ -119,7 +119,6 @@ public:
     void setLightCacheNeedsToBeRebuilt(bool needsToBeRebuilt);
     bool lightCacheNeedsToBeRebuilt() const;
 
-    static int defaultJobCount();
     int optimalJobCount() const;
     void setOptimalJobCount(int v);
 
diff --git a/src/plugins/renderers/rhi/renderer/renderer.cpp b/src/plugins/renderers/rhi/renderer/renderer.cpp
index 184c94e78..345fffdf8 100644
--- a/src/plugins/renderers/rhi/renderer/renderer.cpp
+++ b/src/plugins/renderers/rhi/renderer/renderer.cpp
@@ -2313,7 +2313,7 @@ std::vector<Qt3DCore::QAspectJobPtr> Renderer::renderBinJobs()
                 m_updatedDisableSubtreeEnablers.push_back(node->peerId());
         }
 
-        int idealThreadCount = QThreadPooler::maxThreadCount();
+        int idealThreadCount = QAspectJobManager::idealThreadCount();
 
         const size_t fgBranchCount = m_frameGraphLeaves.size();
         if (fgBranchCount > 1) {
diff --git a/src/plugins/renderers/rhi/renderer/renderviewbuilder.cpp b/src/plugins/renderers/rhi/renderer/renderviewbuilder.cpp
index 138d53612..832f550eb 100644
--- a/src/plugins/renderers/rhi/renderer/renderviewbuilder.cpp
+++ b/src/plugins/renderers/rhi/renderer/renderviewbuilder.cpp
@@ -393,26 +393,6 @@ bool RenderViewBuilder::lightCacheNeedsToBeRebuilt() const
     return m_rebuildFlags.testFlag(RebuildFlag::LightCacheRebuild);
 }
 
-int RenderViewBuilder::defaultJobCount()
-{
-    static int jobCount = 0;
-    if (jobCount)
-        return jobCount;
-
-    const QByteArray maxThreadCount = qgetenv("QT3D_MAX_THREAD_COUNT");
-    if (!maxThreadCount.isEmpty()) {
-        bool conversionOK = false;
-        const int maxThreadCountValue = maxThreadCount.toInt(&conversionOK);
-        if (conversionOK) {
-            jobCount = maxThreadCountValue;
-            return jobCount;
-        }
-    }
-
-    jobCount = QThread::idealThreadCount();
-    return jobCount;
-}
-
 int RenderViewBuilder::optimalJobCount() const
 {
     return m_optimalParallelJobCount;
diff --git a/src/plugins/renderers/rhi/renderer/renderviewbuilder_p.h b/src/plugins/renderers/rhi/renderer/renderviewbuilder_p.h
index 790d2d5e6..f7c4f606c 100644
--- a/src/plugins/renderers/rhi/renderer/renderviewbuilder_p.h
+++ b/src/plugins/renderers/rhi/renderer/renderviewbuilder_p.h
@@ -118,7 +118,6 @@ public:
     void setLightCacheNeedsToBeRebuilt(bool needsToBeRebuilt);
     bool lightCacheNeedsToBeRebuilt() const;
 
-    static int defaultJobCount();
     int optimalJobCount() const;
     void setOptimalJobCount(int v);
 
diff --git a/src/render/jobs/calcboundingvolumejob.cpp b/src/render/jobs/calcboundingvolumejob.cpp
index e11651628..02cdce0ca 100644
--- a/src/render/jobs/calcboundingvolumejob.cpp
+++ b/src/render/jobs/calcboundingvolumejob.cpp
@@ -43,6 +43,7 @@
 #include <Qt3DCore/qboundingvolume.h>
 #include <Qt3DCore/private/qabstractfrontendnodemanager_p.h>
 #include <Qt3DCore/private/qgeometry_p.h>
+#include <Qt3DCore/private/qaspectjobmanager_p.h>
 #include <Qt3DRender/private/nodemanagers_p.h>
 #include <Qt3DRender/private/entity_p.h>
 #include <Qt3DRender/private/renderlogging_p.h>
@@ -469,7 +470,7 @@ void CalculateBoundingVolumeJob::run()
     updatedGeometries.reserve(entities.size());
 
 #if QT_CONFIG(concurrent)
-    if (entities.size() > 1) {
+    if (entities.size() > 1 && QAspectJobManager::idealThreadCount() > 1) {
         UpdateBoundFunctor functor;
         functor.manager = m_manager;
         ReduceUpdateBoundFunctor reduceFunctor;
diff --git a/tests/auto/render/opengl/renderer/tst_renderer.cpp b/tests/auto/render/opengl/renderer/tst_renderer.cpp
index 1e83d8ab2..d4a11fa14 100644
--- a/tests/auto/render/opengl/renderer/tst_renderer.cpp
+++ b/tests/auto/render/opengl/renderer/tst_renderer.cpp
@@ -140,9 +140,9 @@ private Q_SLOTS:
         // filterEntityByLayerJob,
         // syncFilterEntityByLayerJob
 
-        const int singleRenderViewCommandRebuildJobCount  = 1 + Qt3DRender::Render::OpenGL::RenderViewBuilder::defaultJobCount();
+        const int singleRenderViewCommandRebuildJobCount  = 1 + Qt3DCore::QAspectJobManager::idealThreadCount();
 
-        const int singleRenderViewJobCount = 8 + 1 * Qt3DRender::Render::OpenGL::RenderViewBuilder::defaultJobCount();
+        const int singleRenderViewJobCount = 8 + 1 * Qt3DCore::QAspectJobManager::idealThreadCount();
         // RenderViewBuilder renderViewJob,
         //                   syncRenderViewInitializationJob,
         //                   syncFrustumCullingJob,
diff --git a/tests/auto/render/opengl/renderviewbuilder/tst_renderviewbuilder.cpp b/tests/auto/render/opengl/renderviewbuilder/tst_renderviewbuilder.cpp
index 6627e3c08..ec9999e94 100644
--- a/tests/auto/render/opengl/renderviewbuilder/tst_renderviewbuilder.cpp
+++ b/tests/auto/render/opengl/renderviewbuilder/tst_renderviewbuilder.cpp
@@ -259,9 +259,9 @@ private Q_SLOTS:
             QVERIFY(renderViewBuilder.filterEntityByLayerJob().isNull());
             QVERIFY(renderViewBuilder.syncFilterEntityByLayerJob().isNull());
 
-            QCOMPARE(renderViewBuilder.renderViewCommandUpdaterJobs().size(), Qt3DRender::Render::OpenGL::RenderViewBuilder::defaultJobCount());
+            QCOMPARE(renderViewBuilder.renderViewCommandUpdaterJobs().size(), Qt3DCore::QAspectJobManager::idealThreadCount());
             QCOMPARE(renderViewBuilder.materialGathererJobs().size(), 0);
-            QCOMPARE(renderViewBuilder.buildJobHierachy().size(), 8 + 1 * Qt3DRender::Render::OpenGL::RenderViewBuilder::defaultJobCount());
+            QCOMPARE(renderViewBuilder.buildJobHierachy().size(), 8 + 1 * Qt3DCore::QAspectJobManager::idealThreadCount());
         }
 
         {