message: Bugfix: add missing synchronization
diff: @@ -4,6 +4,7 @@ GPUdi() int AliHLTTPCCATrackletConstructor::FetchTracklet(GPUconstant() MEM_CONS
  {
  const int nativeslice = get_group_id(0) % tracker.GPUParametersConst()->fGPUnSlices;
  const int nTracklets = *tracker.NTracklets();
  + GPUsync();
  if (get_local_id(0) == 0)
  {
  if (sMem.fNextTrackletFirstRun == 1)
  @@ -46,12 +47,11 @@ GPUdi() void AliHLTTPCCATrackletConstructor::AliHLTTPCCATrackletConstructorGPU(G
  AliHLTTPCCAThreadMemory rMem;
  - int tmpTracklet;
  - while ((tmpTracklet = FetchTracklet(tracker, sMem)) != -2)
  + while ((rMem.fItr = FetchTracklet(tracker, sMem)) != -2)
  {
  - if (tmpTracklet >= 0 && get_local_id(0) < HLTCA_GPU_THREAD_COUNT_CONSTRUCTOR)
  + if (rMem.fItr >= 0 && get_local_id(0) < HLTCA_GPU_THREAD_COUNT_CONSTRUCTOR)
  {
  - rMem.fItr = tmpTracklet + get_local_id(0);
  + rMem.fItr += get_local_id(0);
  }
  else
  {
  @@ -69,8 +69,8 @@ GPUdi() void AliHLTTPCCATrackletConstructor::AliHLTTPCCATrackletConstructorGPU(G
  {
  reinterpret_cast<GPUsharedref() int*>(&sMem.fRows)[i] = reinterpret_cast<GPUglobalref() int*>(tracker.SliceDataRows())[i];
  }
  - currentSlice = mySlice;
  GPUsync();
  + currentSlice = mySlice;
  }
  if (rMem.fItr >= 0 && rMem.fItr < sMem.fNTracklets)
  