PHOLD — the standard PDES stress benchmark (spec §14.1).
Each LP, on processing an event, schedules exactly one new event to a random target LP at a random future time. The event population is therefore constant; a run is a fixed number of "tokens" bouncing around the LP graph. Tunable target distribution and timestamp increment exercise the rollback machinery under controllable conflict.
Purity is honoured (§8): all randomness comes from a TimeWarp.Rand carried in
model_state, seeded per-LP so no two LPs share a generator. Rollback restores
the generator with the state snapshot, so re-execution is bit-identical — which
is exactly what the sequential-equivalence oracle and the Divergence Detector
rely on.