Adapt event buffering to time order violations

When a time order violation occurs, we double the event buffer size.
This makes further time order violations less likely. Furthermore, if we
were running in automatic buffer mode (by FINISHED_ROUND) and catch a
violation, then we switch back to dynamic buffer mode. A new command
line option is introduced to limit the maximum buffer size.

Change-Id: I1f1c4d3f630ecec420babe09e737e2dbd8bb25ca
Task-number: QTCREATORBUG-20455
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>

1 files changed, 12 insertions, 1 deletions

diff --git a/app/perfunwind.h b/app/perfunwind.h
index 82713a3..b5bff8b 100644
--- a/app/perfunwind.h
+++ b/app/perfunwind.h
@@ -157,7 +157,10 @@ public:
     void setIgnoreKallsymsBuildId(bool ignore) { m_ignoreKallsymsBuildId = ignore; }
 
     uint maxEventBufferSize() const { return m_maxEventBufferSize; }
-    void setMaxEventBufferSize(uint size) { m_maxEventBufferSize = size; }
+    void setMaxEventBufferSize(uint size);
+
+    uint targetEventBufferSize() const { return m_targetEventBufferSize; }
+    void setTargetEventBufferSize(uint size);
 
     int maxUnwindFrames() const { return m_currentUnwind.maxFrames; }
     void setMaxUnwindFrames(int maxUnwindFrames) { m_currentUnwind.maxFrames = maxUnwindFrames; }
@@ -277,8 +280,13 @@ private:
     QVector<PerfEventAttributes> m_attributes;
     QHash<QByteArray, QByteArray> m_buildIds;
 
+    uint m_lastEventBufferSize;
     uint m_maxEventBufferSize;
+    uint m_targetEventBufferSize;
     uint m_eventBufferSize;
+
+    uint m_timeOrderViolations;
+
     quint64 m_lastFlushMaxTime;
     QSysInfo::Endian m_byteOrder = QSysInfo::LittleEndian;
 
@@ -299,6 +307,9 @@ private:
     void flushEventBuffer(uint desiredBufferSize);
 
     QVariant readTraceData(const QByteArray &data, const FormatField &field, bool byteSwap);
+    void forwardMmapBuffer(QList<PerfRecordMmap>::Iterator &it,
+                           const QList<PerfRecordMmap>::Iterator &mmapEnd,
+                           quint64 timestamp);
 };
 
 uint qHash(const PerfUnwind::Location &location, uint seed = 0);