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Merged
seando-adsk merged 2 commits into from
Jul 7, 2026
Merged

EMSUSD-3880 Optimizes Multi-stage loading performance #4660

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a92444d
EMSUSD-3880 Optimizes Multi-stage loading performance
AramAzhari-adsk Jul 3, 2026
f5f5dfc
Fixes a warning treated as error on Linux
AramAzhari-adsk Jul 3, 2026
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13 changes: 9 additions & 4 deletions lib/usd/ui/layerEditor/layerTreeModel.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -297,13 +297,17 @@ void LayerTreeModel::setSessionState(SessionState* in_sessionState)
rebuildModelOnIdle(true);
}

void LayerTreeModel::rebuildModelOnIdle(bool dataChanged)
void LayerTreeModel::rebuildModelOnIdle(bool dataChanged, bool refreshLockState)
{
// Coalesce rebuilds within one event-loop turn into a single rebuild. Accumulate
// the strongest request across coalesced callers (data-changed and lock-refresh).
_selectedLayerDataChanged |= dataChanged;
_rebuildOnIdleRefreshLockState = _rebuildOnIdleRefreshLockState || refreshLockState;
if (!_rebuildOnIdlePending) {
_rebuildOnIdlePending = true;
QTimer::singleShot(0, this, [this]() {
bool refreshLockState = false;
const bool refreshLockState = _rebuildOnIdleRefreshLockState;
_rebuildOnIdleRefreshLockState = false;
this->rebuildModel(refreshLockState);
});
}
Expand Down Expand Up @@ -527,8 +531,9 @@ void LayerTreeModel::usd_layerDirtinessChanged(
// called from SessionState::currentStageChangedSignal
void LayerTreeModel::sessionStageChanged()
{
bool refreshLockState = true;
rebuildModel(refreshLockState);
// Coalesce: a burst of stage changes collapses into one rebuild instead of
// rebuilding synchronously on every change.
rebuildModelOnIdle(/*dataChanged*/ false, /*refreshLockState*/ true);
}

// called from SessionState::autoHideSessionLayerSignal
Expand Down
3 changes: 2 additions & 1 deletion lib/usd/ui/layerEditor/layerTreeModel.h
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Original file line number Diff line number Diff line change
Expand Up @@ -150,9 +150,10 @@ class LayerTreeModel

mutable int _lastAskedAnonLayerNameSinceRebuild = 0;

void rebuildModelOnIdle(bool dataChanged = false);
void rebuildModelOnIdle(bool dataChanged = false, bool refreshLockState = false);
bool _rebuildOnIdlePending = false;
bool _selectedLayerDataChanged = false;
bool _rebuildOnIdleRefreshLockState = false;
void rebuildModel(bool refreshLockState = false);

void updateTargetLayer(InRebuildModel inRebuild);
Expand Down
16 changes: 15 additions & 1 deletion lib/usd/ui/layerEditor/layerTreeView.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,7 @@
#include <maya/MGlobal.h>
#include <maya/MQtUtil.h>

#include <QtCore/QTimer>
#include <QtGui/QColor>
#include <QtGui/QCursor>
#include <QtWidgets/QMenu>
Expand Down Expand Up @@ -140,7 +141,7 @@ LayerTreeView::LayerTreeView(SessionState* in_sessionState, QWidget* in_parent)
_model->sessionState(),
&SessionState::stageListChangedSignal,
this,
&LayerTreeView::updateFromSessionState);
&LayerTreeView::updateFromSessionStateOnIdle);

auto buttonDefinitions = LayerTreeItem::actionButtonsDefinition();
auto muteActionIter = buttonDefinitions.find(LayerActionType::Mute);
Expand Down Expand Up @@ -352,6 +353,19 @@ void LayerViewMemento::restore(LayerTreeView& view, LayerTreeModel& model)
}
}

// Coalesce a burst of stageListChangedSignal notifications into a single refresh
// (updateFromSessionState re-scans all stages, so avoid doing it per stage).
void LayerTreeView::updateFromSessionStateOnIdle()
{
if (!_updateFromSessionStatePending) {
_updateFromSessionStatePending = true;
QTimer::singleShot(0, this, [this]() {
_updateFromSessionStatePending = false;
updateFromSessionState();
});
}
}

void LayerTreeView::updateFromSessionState()
{
if (_cachedModelState == nullptr) {
Expand Down
3 changes: 3 additions & 0 deletions lib/usd/ui/layerEditor/layerTreeView.h
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Original file line number Diff line number Diff line change
Expand Up @@ -147,6 +147,9 @@ class LayerTreeView

// Updates the _cachedModelState using stage data from the session
void updateFromSessionState();
// Coalesced updateFromSessionState (one refresh per event-loop turn).
void updateFromSessionStateOnIdle();
bool _updateFromSessionStatePending { false };

LayerTreeViewStyle _treeViewStyle;
QPointer<LayerTreeModel> _model;
Expand Down
80 changes: 38 additions & 42 deletions lib/usd/ui/layerEditor/stageSelectorWidget.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -36,36 +36,31 @@
#include <ufe/selectionNotification.h>

#include <QtCore/QSignalBlocker>
#include <QtCore/QTimer>
#include <QtWidgets/QHBoxLayout>
#include <QtWidgets/QLabel>

Q_DECLARE_METATYPE(UsdLayerEditor::SessionState::StageEntry);

namespace {

int getEntryIndexById(
const std::string& id,
std::vector<UsdLayerEditor::SessionState::StageEntry> const& stages)
// Find the combo index whose stored StageEntry matches id, or -1. Used instead of
// SessionState::allStages() (a full DAG scan) so per-stage handlers stay O(combo).
int comboIndexById(const QComboBox* dropDown, const std::string& id)
{
auto it = std::find_if(
stages.begin(), stages.end(), [&id](UsdLayerEditor::SessionState::StageEntry stageEntry) {
return (id == stageEntry._id);
});

if (it != stages.end()) {
return std::distance(stages.begin(), it);
for (int i = 0, count = dropDown->count(); i < count; ++i) {

@seando-adsk seando-adsk Jul 6, 2026

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Do we need to guard against input dropDown == nullptr?

@AramAzhari-adsk AramAzhari-adsk Jul 6, 2026 •
edited
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Good suggestion. It seems that dropdown is only created in a constructor once and never reset (not even in the destructor). So at all the callers' location the dropDown is guaranteed non-null for the widget's entire lifetime.

I could still add this if it's blocking this PR, or take a note and improve it later.

   if (!dropDown)
        return -1;

// Bind itemData() to a named QVariant so value<>() uses the const-lvalue
// overload. Calling value<>() directly on the returned rvalue selects the
// move overload, which move-constructs StageEntry and trips a spurious
// -Werror=array-bounds under GCC.
const QVariant data = dropDown->itemData(i);
if (data.value<UsdLayerEditor::SessionState::StageEntry>()._id == id) {
return i;
}
}

return -1;
}

int getEntryIndexById(
UsdLayerEditor::SessionState::StageEntry const& entry,
std::vector<UsdLayerEditor::SessionState::StageEntry> const& stages)
{
return getEntryIndexById(entry._id, stages);
}

bool loadStagePinnedOption()
{
const MString optionName = PXR_NS::MayaUsdOptionVars->PinLayerEditorStage.GetText();
Expand Down Expand Up @@ -241,7 +236,7 @@ void StageSelectorWidget::setSessionState(SessionState* in_sessionState)
_sessionState,
&SessionState::stageListChangedSignal,
this,
&StageSelectorWidget::updateFromSessionState);
&StageSelectorWidget::updateFromSessionStateOnIdle);
connect(
_sessionState,
&SessionState::currentStageChangedSignal,
Expand Down Expand Up @@ -269,6 +264,23 @@ SessionState::StageEntry const StageSelectorWidget::selectedStage()

return SessionState::StageEntry();
}
// Coalesce a burst of stageListChangedSignal notifications into a single dropdown
// rebuild (last requested selection wins). Avoids a per-stage rebuild + DAG scan.
void StageSelectorWidget::updateFromSessionStateOnIdle(
SessionState::StageEntry const& entryToSelect)
{
_pendingSelectEntry = entryToSelect;
if (!_updateFromSessionStatePending) {
_updateFromSessionStatePending = true;
QTimer::singleShot(0, this, [this]() {
_updateFromSessionStatePending = false;
const SessionState::StageEntry entry = _pendingSelectEntry;
_pendingSelectEntry = SessionState::StageEntry();
updateFromSessionState(entry);
});
}
}

// repopulates the combo based on the session stage list
void StageSelectorWidget::updateFromSessionState(SessionState::StageEntry const& entryToSelect)
{
Expand Down Expand Up @@ -326,9 +338,6 @@ void StageSelectorWidget::selectionChanged()
if (!ufeGlobalSelection)
return;

std::vector<SessionState::StageEntry> allStages;
bool allStagesFilled = false;

// We will set the currently selected stage to be the stage of the first item
// that is a USD item. So if multiple stages are selected, the first one wins.
const Ufe::Selection& ufeSelection = *ufeGlobalSelection;
Expand All @@ -337,14 +346,9 @@ void StageSelectorWidget::selectionChanged()
if (!proxyShapePtr)
continue;

if (!allStagesFilled) {
allStages = _sessionState->allStages();
allStagesFilled = true;
}

MFnDagNode dagNode(proxyShapePtr->thisMObject());
const std::string id = dagNode.uuid().asString().asChar();
const int index = getEntryIndexById(id, allStages);
const int index = comboIndexById(_dropDown, id);
if (index == -1)
continue;

Expand Down Expand Up @@ -393,7 +397,7 @@ void StageSelectorWidget::updateContentButton()
void StageSelectorWidget::sessionStageChanged()
{
if (!_internalChange) {
auto index = getEntryIndexById(_sessionState->stageEntry(), _sessionState->allStages());
auto index = comboIndexById(_dropDown, _sessionState->stageEntry()._id);
if (index != -1) {
QSignalBlocker blocker(_dropDown);
_dropDown->setCurrentIndex(index);
Expand All @@ -403,7 +407,7 @@ void StageSelectorWidget::sessionStageChanged()

void StageSelectorWidget::stageRenamed(SessionState::StageEntry const& renamedEntry)
{
auto index = getEntryIndexById(renamedEntry, _sessionState->allStages());
auto index = comboIndexById(_dropDown, renamedEntry._id);
if (index != -1) {
_dropDown->setItemText(index, renamedEntry._displayName.c_str());
_dropDown->setItemData(index, QVariant::fromValue(renamedEntry));
Expand All @@ -412,18 +416,10 @@ void StageSelectorWidget::stageRenamed(SessionState::StageEntry const& renamedEn

void StageSelectorWidget::stageReset(SessionState::StageEntry const& entry)
{
// Individual combo box entries have a short display name and a reference to a stage,
// which is not a unique combination. By construction the combo box indices do line
// up with the SessionState StageEntry vector though, so in the case of resetting
// a proxy we will find the matching full proxy path in that vector and use its index
// to update the combo box.
auto count = _dropDown->count();
if (count <= 0) {
return;
}

auto index = getEntryIndexById(entry, _sessionState->allStages());
if (index >= 0 && index < count) {
// Refresh only the matching combo item's data, matched locally by id, instead
// of SessionState::allStages() (a full DAG scan) — this fires O(N) times.
const int index = comboIndexById(_dropDown, entry._id);
if (index != -1) {
_dropDown->setItemData(index, QVariant::fromValue(entry));
}
}
Expand Down
7 changes: 7 additions & 0 deletions lib/usd/ui/layerEditor/stageSelectorWidget.h
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Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,9 @@ class StageSelectorWidget : public QWidget
// slot:
void updateFromSessionState(
SessionState::StageEntry const& entryToSelect = SessionState::StageEntry());
// Coalesced updateFromSessionState (one dropdown rebuild per event-loop turn).
void updateFromSessionStateOnIdle(
SessionState::StageEntry const& entryToSelect = SessionState::StageEntry());
void stageRenamed(SessionState::StageEntry const& renamedEntry);
void stageReset(SessionState::StageEntry const& entry);
void sessionStageChanged();
Expand All @@ -64,6 +67,10 @@ class StageSelectorWidget : public QWidget
QPushButton* _collapseContent { nullptr };
bool _internalChange { false }; // for notifications
bool _pinStageSelection { true };

// Coalescing state for updateFromSessionStateOnIdle().
bool _updateFromSessionStatePending { false };
SessionState::StageEntry _pendingSelectEntry;
};

} // namespace UsdLayerEditor
Expand Down
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