If you see your Linux CPU utilization spike to 100% system (kernel) on
all cores, you may be running into a "Transparent Hugepage"
issue. Just execute the following as root to disable the problematic,
optional feature:
echo never > /sys/kernel/mm/transparent_hugepage/defrag
Details
This feature of the Linux kernel is widely reported to have issues
with 3.6 kernels. It is especially noticeable when running Java code
that does large disk reads or writes.