We have observed that the Zero runtime can lock up on alpha, especially on SMP machines running Linux. This manifests itself in the OpenJDK taking forever by repeatedly printing "compiler/java/jar running ..." and never finishing.

It can be worked around by booting the machine with a uni-processor kernel. The fix is to use __sync_synchronize() even for the LIGHT_MEM_BARRIER in src/os_cpu/linux_zero/vm/orderAccess_linux_zero.inline.hpp.