import resource, time

def workload(rounds):

    x = 0
    for i in range(rounds):
        x = x + 1

def microbench():

    print 'Microbench'
    sleeptime = 10e-6
    sleep = time.sleep
    timer = time.time
    rtype = resource.RUSAGE_SELF
    rounds = 100

    while 1:
        times = []
        rstart = resource.getrusage(rtype)
        for i in range(100):
            # Make sure the test is run at the start of a scheduling time
            # slice
            sleep(sleeptime)
            # Test
            start = timer()
            workload(rounds)
            stop = timer()
            times.append(stop - start)
        rstop = resource.getrusage(rtype)
        volswitches = rstop[-2] - rstart[-2]
        forcedswitches = rstop[-1] - rstart[-1]
        min_time = min(times)
        max_time = max(times)
        diff = max_time - min_time
        if forcedswitches == 0:
            print 'Rounds: %i' % rounds
            print '  min time: %f seconds' % min_time
            print '  max time: %f seconds' % max_time
            print '  diff: %f %% = %f seconds' % (diff / min_time * 100.0,
                                                  diff)
            print '  context switches: %r %r' % (volswitches, forcedswitches)
            print
        elif forcedswitches > 10:
            break
        rounds += 100

microbench()