simgrid::kernel::activity::ExecImplPtr exec =
boost::static_pointer_cast<simgrid::kernel::activity::ExecImpl>(synchro);
if(exec->surf_exec)
simgrid::kernel::activity::ExecImplPtr exec =
boost::static_pointer_cast<simgrid::kernel::activity::ExecImpl>(synchro);
if(exec->surf_exec)