'Get the status of monitoring.
:param pids: List of PIDs you intend to control. Use pids=[] to control
all defined PIDs.
:return:
tuple([cpu load], [memory load]):
([(PID1, (PID1_cpu_meas)), (PID2, (PID2_cpu_meas)), ...],
[(PID1, (PID1_mem_meas)), (PID2, (PID2_mem_meas)), ...])
PID1_cpu_meas:
average_values[], test_time, cont_meas_values[[]], time_step
PID1_mem_meas:
average_values[], test_time, cont_meas_values[[]], time_step
where average_values[] are the measured values (mem_free,swap,...)
which are described in SystemLoad.__init__()-FileFieldMonitor.
cont_meas_values[[]] is a list of average_values in the sampling
times.'

def dump(self, pids=[]):

    if (pids == []):
        pids = self.pids
    cpus = []
    memory = []
    for pid in pids:
        stat = (pid, self.stats[pid][1].get_status())
        cpus.append(stat)
    for pid in pids:
        stat = (pid, self.stats[pid][2].get_status())
        memory.append(stat)
    return (cpus, memory)
