def unicore_cpu_budget(budget):
    """The maximum single-core CPU budget."""
    if budget.cpu_seconds is None:
        if budget.wall_seconds is None:
            return 100000000.0
        else:
            return budget.wall_seconds
    elif budget.wall_seconds is None:
        return budget.cpu_seconds
    else:
        return min(budget.cpu_seconds, budget.wall_seconds)
