The node is a execution component that is defined with queue size and latency (using step as unit). the chain chains node as a line. The simulator is driven by "step". We try to see how the executor stall and the change of the queue unitilization.

We assume there are n threads which share the same spinlock, we try to figure out the behavior of the waiting queue

this is a simple cpu simulator to show how cpu is work. see README.rst in the directory for detail