def sync_improves_metric(max_demand, sync_periods, timesteps, workload_name,
ctrl_name, name=None, sa=0.3, ia=10, shape=0.5, show_graph=False, staleness=0):
"""Evalute the value of synchronization for a LinkBalanerCtrl by showing
its effect on performance metric. We expect that for a workload which
imparts server link imbalance across multiple domains, syncing will help
improve the rmse_server metric.
sa: the sslbc fractional load-balancing scale factor (0,1]. Controls what
fraction of the imbalance we re-balance at each handle_request
ia: the mean parameter for the expnentially distributed inter-arrival times
of the expo workflow (value of x leads to mean of 1/x). Gets passed to
random.expovariate(ia)
shape: the weibull distribution shape parameter for flow duration
"""
if name == None:
name = sys._getframe().f_code.co_name + "_" + ctrl_name + "_" + workload_name
#for sync_period in [0] + [2**(x) for x in range(0, int(log(timesteps,2)))]:
for sync_period in sync_periods:
sync_period = float(sync_period)
myname = '%(a)s_%(b)d_%(c)02d_%(d)01d' % {"a": name,
"b": max_demand,
"c": sync_period,
"d": staleness}
logger.info("starting %s", myname)
if workload_name == 'expo':
wave_period = timesteps/4
old_style=False
workload = expo_workload(switches=['sw1', 'sw2'],
period=wave_period, interarrival_alpha=ia,
duration_shape=shape, timesteps=timesteps)
elif workload_name == 'wave':
old_style=True
wave_period = timesteps/4
workload = dual_offset_workload(switches=['sw1', 'sw2'],
period=wave_period, offset=wave_period/2.0,
max_demand=max_demand, size=1,
duration=2, timesteps=timesteps,
workload_fcn=wave, y_shift=(1.0/3))
else:
assert "No Valid Workload Specified"
if ctrl_name == 'separate':
ctrls = two_separate_state_ctrls(alpha=sa)
elif ctrl_name == 'lbc':
ctrls = two_ctrls()
else:
assert "No Valid Controller Specified"
sim = LinkBalancerSim(two_switch_topo(), ctrls)
sim.run_and_trace(myname, workload, old=old_style, sync_period=sync_period,
show_graph=show_graph, staleness=staleness,
ignore_remaining=True)
logger.info("ending %s", myname)
def compare_random_dist_to_centralized(period=64, max_demand=8, show_graph=False):
""" """
timesteps = period * 4
for sync_period in [0] + [2**x for x in range(0, int(log(period,2)))]:
myname = '%(fname)s_%(num)02d' % {"fname": sys._getframe().f_code.co_name, "num": sync_period}
logger.info("starting %s", myname)
workload = dual_offset_workload(switches=['sw1', 'sw2'],
period=period, offset=period/2.0,
max_demand=max_demand, size=1,
duration=2, timesteps=timesteps,
workload_fcn=wave)
ctrls = two_random_ctrls()
sim = LinkBalancerSim(two_switch_topo(), ctrls)
sim.run_and_trace(myname, workload, old=True, sync_period=sync_period,
show_graph=show_graph)
logger.info("ending %s", myname)
def synced_dist_equals_central(period=64, max_demand=4, show_graph=False):
"""Ensure that a distributed controller simulation run with sync_period=0
yields exactly the same result as the same toplology and workload with a
single controller."""
timesteps = period * 4
for sync_period in [0] + [2**x for x in range(0, int(log(period,2)))]:
myname = '%(fname)s_%(num)02d' % {"fname": sys._getframe().f_code.co_name, "num": sync_period}
logger.info("starting %s", myname)
workload = dual_offset_workload(switches=['sw1', 'sw2'],
period=period, offset=0,
max_demand=max_demand, size=1,
duration=1, timesteps=timesteps,
workload_fcn=wave)
ctrls = two_ctrls()
sim = LinkBalancerSim(two_switch_topo(), ctrls)
sim.run_and_trace(myname+str(sync_period), workload, old=True, sync_period=sync_period,
show_graph=show_graph)
logger.info("ending %s", myname)
def demo_strictly_local_ctrls(max_demand=8, show_graph=False):
"""Demonstrate synchronization across domains makes no difference when
LinkBalanerCtrl only handles requests within its own domain"""
#TODO: demonstrate with more than 1 srv per controller domain
period = 32
timesteps = period * 4
for sync_period in [0] + [2**x for x in range(0, int(log(period,2)))]:
myname = '%(fname)s_%(num)02d' % {"fname": sys._getframe().f_code.co_name, "num": sync_period}
logger.info("starting %s", myname)
workload = dual_offset_workload(switches=['sw1', 'sw2'],
period=period, offset=period/2.0,
max_demand=max_demand, size=1,
duration=1, timesteps=timesteps,
workload_fcn=wave)
ctrls = strictly_local_ctrls()
sim = LinkBalancerSim(two_switch_topo(), ctrls)
sim.run_and_trace(myname, workload, old=True, sync_period=sync_period,
show_graph=show_graph)
logger.info("ending %s", myname)
