GL Delay Measurement

gistfile1.diff

diff --git a/xbmc/rendering/gl/RenderSystemGL.cpp b/xbmc/rendering/gl/RenderSystemGL.cpp
index ae10d3e..b334d45 100644
--- a/xbmc/rendering/gl/RenderSystemGL.cpp
+++ b/xbmc/rendering/gl/RenderSystemGL.cpp
@@ -34,6 +34,7 @@
 #include "utils/SystemInfo.h"
 #include "utils/MathUtils.h"
 #include "utils/StringUtils.h"
+#include <queue>
 
 CRenderSystemGL::CRenderSystemGL() : CRenderSystemBase()
 {
@@ -323,6 +324,24 @@ bool CRenderSystemGL::PresentRender(const CDirtyRegionList& dirty)
 
   bool result = PresentRenderImpl(dirty);
 
+  static std::queue<GLsync> syncs;
+  static double delay;
+  static int    count = 0;
+#if(1)
+  syncs.push(glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0));
+  delay = delay * 0.9 + 0.1 * syncs.size();
+  while(!syncs.empty())
+  {
+    if(glClientWaitSync(syncs.front(), 0, 0) == GL_TIMEOUT_EXPIRED)
+      break;
+    glDeleteSync(syncs.front());
+    syncs.pop();
+  }
+  if(count++ == 100) {
+    fprintf(stderr, "delay %f\n", delay);
+    count = 0;
+  }
+#endif
   if (m_iVSyncMode && m_iSwapRate != 0)
   {
     int64_t curr, diff;