Concurrency control mechanisms for highly multi-threaded systems

A system for governing the spawning of a thread from a parent thread by an application in a processor:

• one or more registers or memory locations that store values associated with remaining thread credits with respect to a thread, a policy passed by the thread's parent, and a plurality of policy values associated with the thread's parent;
• a first multiplexor module that selects from the one or more registers the policy used to spawn a thread, and makes the policy available for execution;
• a second multiplexor module that selects one or more of the policy values used in
• a spawn process whose policy was selected by the output of the first multiplexor module, the second multiplexor module outputs a first signal indicative of the selected policy value to accompany the selected policy, which may be given to the child thread as its initial spawn count when the policy so indicates;
• and
• then subtracted from the second signal to update the parent's spawn count;
• a third multiplexor module that selects either the first signal or a null where the selected policy value of the first signal is used to update the remaining thread credits of the thread's parent by subtracting the selected policy value from the remaining thread credits.