•Maintain two
orders:
–Regular
serial, depth-first, left-to right execution.
•At each spawn, follow spawn thread before continuation thread
–Right-to-left
execution.
•At each spawn, follow
continuation thread before spawn thread
•Claim: Two threads e1 and e2 are parallel if and only if e1 precedes e2 in one order, and e2 precedes
e1 in the other.