Make deferred tracing less expensive (real-time cost is the same)

2 files changed, 47 insertions, 29 deletions

diff --git a/src/declarative/debugger/qdeclarativedebugtrace.cpp b/src/declarative/debugger/qdeclarativedebugtrace.cpp
index cd4306b..7f970bf 100644
--- a/src/declarative/debugger/qdeclarativedebugtrace.cpp
+++ b/src/declarative/debugger/qdeclarativedebugtrace.cpp
@@ -47,6 +47,20 @@
 
 Q_GLOBAL_STATIC(QDeclarativeDebugTrace, traceInstance);
 
+// convert to a QByteArray that can be sent to the debug client
+// use of QDataStream can skew results if m_deferredSend == false
+//     (see tst_qperformancetimer::trace() benchmark)
+QByteArray QDeclarativeDebugData::toByteArray() const
+{
+    QByteArray data;
+    //### using QDataStream is relatively expensive
+    QDataStream ds(&data, QIODevice::WriteOnly);
+    ds << time << messageType << detailType;
+    if (messageType == (int)QDeclarativeDebugTrace::RangeData)
+        ds << detailData;
+    return data;
+}
+
 QDeclarativeDebugTrace::QDeclarativeDebugTrace()
 : QDeclarativeDebugService(QLatin1String("CanvasFrameRate")),
   m_enabled(false), m_deferredSend(true)
@@ -83,10 +97,8 @@ void QDeclarativeDebugTrace::addEventImpl(EventType event)
     if (status() != Enabled || !m_enabled)
         return;
 
-    QByteArray data;
-    QDataStream ds(&data, QIODevice::WriteOnly);
-    ds << m_timer.elapsed() << (int)Event << (int)event;
-    processMessage(data);
+    QDeclarativeDebugData ed = {m_timer.elapsed(), (int)Event, (int)event, QString()};
+    processMessage(ed);
 }
 
 void QDeclarativeDebugTrace::startRangeImpl(RangeType range)
@@ -94,10 +106,8 @@ void QDeclarativeDebugTrace::startRangeImpl(RangeType range)
     if (status() != Enabled || !m_enabled)
         return;
 
-    QByteArray data;
-    QDataStream ds(&data, QIODevice::WriteOnly);
-    ds << m_timer.elapsed() << (int)RangeStart << (int)range;
-    processMessage(data);
+    QDeclarativeDebugData rd = {m_timer.elapsed(), (int)RangeStart, (int)range, QString()};
+    processMessage(rd);
 }
 
 void QDeclarativeDebugTrace::rangeDataImpl(RangeType range, const QString &rData)
@@ -105,10 +115,8 @@ void QDeclarativeDebugTrace::rangeDataImpl(RangeType range, const QString &rData
     if (status() != Enabled || !m_enabled)
         return;
 
-    QByteArray data;
-    QDataStream ds(&data, QIODevice::WriteOnly);
-    ds << m_timer.elapsed() << (int)RangeData << (int)range << rData;
-    processMessage(data);
+    QDeclarativeDebugData rd = {m_timer.elapsed(), (int)RangeData, (int)range, rData};
+    processMessage(rd);
 }
 
 void QDeclarativeDebugTrace::endRangeImpl(RangeType range)
@@ -116,22 +124,20 @@ void QDeclarativeDebugTrace::endRangeImpl(RangeType range)
     if (status() != Enabled || !m_enabled)
         return;
 
-    QByteArray data;
-    QDataStream ds(&data, QIODevice::WriteOnly);
-    ds << m_timer.elapsed() << (int)RangeEnd << (int)range;
-    processMessage(data);
+    QDeclarativeDebugData rd = {m_timer.elapsed(), (int)RangeEnd, (int)range, QString()};
+    processMessage(rd);
 }
 
 /*
     Either send the message directly, or queue up
     a list of messages to send later (via sendMessages)
 */
-void QDeclarativeDebugTrace::processMessage(const QByteArray &message)
+void QDeclarativeDebugTrace::processMessage(const QDeclarativeDebugData &message)
 {
     if (m_deferredSend)
         m_data.append(message);
     else
-        sendMessage(message);
+        sendMessage(message.toByteArray());
 }
 
 /*
@@ -142,7 +148,7 @@ void QDeclarativeDebugTrace::sendMessages()
     if (m_deferredSend) {
         //### this is a suboptimal way to send batched messages
         for (int i = 0; i < m_data.count(); ++i)
-            sendMessage(m_data.at(i));
+            sendMessage(m_data.at(i).toByteArray());
         m_data.clear();
     }
 }
diff --git a/src/declarative/debugger/qdeclarativedebugtrace_p.h b/src/declarative/debugger/qdeclarativedebugtrace_p.h
index b935fbe..86c0987 100644
--- a/src/declarative/debugger/qdeclarativedebugtrace_p.h
+++ b/src/declarative/debugger/qdeclarativedebugtrace_p.h
@@ -49,18 +49,22 @@ QT_BEGIN_HEADER
 
 QT_BEGIN_NAMESPACE
 
+struct QDeclarativeDebugData
+{
+    qint64 time;
+    int messageType;
+    int detailType;
+    QString detailData;
+
+    QByteArray toByteArray() const;
+};
+
+Q_DECLARE_TYPEINFO(QDeclarativeDebugData,Q_PRIMITIVE_TYPE);
+
 class QUrl;
 class Q_AUTOTEST_EXPORT QDeclarativeDebugTrace : public QDeclarativeDebugService
 {
 public:
-    enum EventType {
-        FramePaint,
-        Mouse,
-        Key,
-
-        MaximumEventType
-    };
-
     enum Message {
         Event,
         RangeStart,
@@ -70,6 +74,14 @@ public:
         MaximumMessage
     };
 
+    enum EventType {
+        FramePaint,
+        Mouse,
+        Key,
+
+        MaximumEventType
+    };
+
     enum RangeType {
         Painting,
         Compiling,
@@ -94,12 +106,12 @@ private:
     void startRangeImpl(RangeType);
     void rangeDataImpl(RangeType, const QString &);
     void endRangeImpl(RangeType);
-    void processMessage(const QByteArray &);
+    void processMessage(const QDeclarativeDebugData &);
     void sendMessages();
     QPerformanceTimer m_timer;
     bool m_enabled;
     bool m_deferredSend;
-    QList<QByteArray> m_data;
+    QList<QDeclarativeDebugData> m_data;
 };
 
 QT_END_NAMESPACE