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Further efficiency improvements

This commit is contained in:
Vitalik Buterin 2015-09-01 09:25:33 -04:00
parent 02ac09a8d0
commit 5bbca50547
1 changed files with 76 additions and 42 deletions
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118
casper/casper.py
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@ -6,8 +6,8 @@ import math
NUM_VALIDATORS = 20
BLKTIME = 40
BY_CHAIN = False
NETSPLITS = False
NETSPLITS = 2
CHECK_INTEGRITY = True
GENESIS_STATE = 0
@ -31,6 +31,9 @@ class Signature():
# Finalized height
self.sign_from = sign_from
def get_height(self):
return self.sign_from + len(self.probs)
class Block():
def __init__(self, maker, height):
@ -42,6 +45,13 @@ class Block():
self.hash = random.randrange(10**20) + 10**21 + 10**23 * self.height
class BlockRequest():
def __init__(self, sender, height):
self.sender = sender
self.ask_height = height
self.hash = random.randrange(10**14)
def state_transition(state, block):
return state if block is None else (state ** 3 + block.hash ** 5) % 10**40
@ -83,28 +93,41 @@ class Validator():
def get_time(self):
return self.network.time + self.time_offset
def broadcast(self, obj):
self.network.broadcast(self, obj)
def sign(self, block):
# Initialize the probability array, the core of the signature
best_guesses = [None] * len(self.received_blocks)
sign_from = max(0, self.max_finalized_height - 30)
for i, b in list(enumerate(self.received_blocks))[sign_from:]:
if self.received_blocks[i] is None:
time_delta = self.get_time() - BLKTIME * i
time_delta = self.get_time() - BLKTIME * i
my_opinion = 0.35 / (1 + max(0, time_delta) * 0.2 / BLKTIME) + 0.14
else:
time_delta = self.time_received[b.hash] - BLKTIME * i
time_delta = self.time_received[b.hash] - BLKTIME * i
my_opinion = 0.7 / (1 + abs(time_delta) * 0.2 / BLKTIME) + 0.15
# print 'tdpost', time_delta, my_opinion
if my_opinion == 0.5:
my_opinion = 0.5001
votes = self.received_signatures[i].values() if i < len(self.received_signatures) else []
votes += [my_opinion] * (NUM_VALIDATORS - len(votes))
best_guesses[i] = min(vote(votes), 1 if self.received_blocks[i] is not None else my_opinion)
vote_from_signatures = vote(votes)
bg = min(vote_from_signatures, 1 if self.received_blocks[i] is not None else my_opinion)
# In case we fall into an equilibrium trap at 0.5, eventually force divergence
if self.get_time() - BLKTIME * i > BLKTIME * 40:
fac = 1.0 / (1.0 + (self.get_time() - BLKTIME * i) / (BLKTIME * 40))
if 0.14 < bg < 1 - 0.5 * fac:
bg = 0.14 + (bg - 0.14) * fac
best_guesses[i] = bg
if vote_from_signatures > 0.95 and self.received_blocks[i] is None:
self.broadcast(BlockRequest(self.id, i))
if best_guesses[i] > 0.9999:
while len(self.finalized_hashes) <= i:
self.finalized_hashes.append(None)
self.finalized_hashes[i] = self.received_blocks[i].hash
elif best_guesses[i] < 0.0001:
elif best_guesses[i] < 0.0001:
while len(self.finalized_hashes) <= i:
self.finalized_hashes.append(None)
self.finalized_hashes[i] = False
@ -113,7 +136,7 @@ class Validator():
self.max_finalized_height += 1
last_state = self.finalized_states[-1] if len(self.finalized_states) else GENESIS_STATE
self.finalized_states.append(state_transition(last_state, self.received_blocks[self.max_finalized_height]))
self.probs = self.probs[:sign_from] + best_guesses[sign_from:]
log('Making signature: %r' % self.probs[-10:], lvl=1)
sign_from_state = self.finalized_states[sign_from - 1] if sign_from > 0 else GENESIS_STATE
@ -144,14 +167,11 @@ class Validator():
for i, p in enumerate(obj.probs):
self.received_signatures[i + obj.sign_from][obj.signer] = p
self.network.broadcast(self, obj)
# Received an object request, respond if we have it
elif isinstance(obj, ObjRequest):
if obj.ask_hash in self.received_objects:
self.network.direct_send(obj.sender_id, ObjResponse(
self.received_objects[obj.ask_hash]))
# Received an object response, add to database
elif isinstance(obj, ObjResponse):
self.received_objects[obj.obj.hash] = obj.obj
# Received a block request, respond if we have it
elif isinstance(obj, BlockRequest):
if obj.ask_height < len(self.received_blocks):
if self.received_blocks[obj.ask_height] is not None:
self.network.direct_send(obj.sender, self.received_blocks[obj.ask_height])
self.received_objects[obj.hash] = obj
self.time_received[obj.hash] = self.get_time()
@ -180,12 +200,15 @@ all_signatures = []
now = [0]
def who_heard_of(h, n):
o = ''
for x in n.agents:
o += '1' if h in x.received_objects else '0'
return o
o = ''
for x in n.agents:
o += '1' if h in x.received_objects else '0'
return o
ALPHA = '0123456789'
def get_opinions(n):
o = []
@ -197,20 +220,23 @@ def get_opinions(n):
q = ''
for x in n.agents:
if len(x.probs) <= h:
p += '_'
elif x.probs[h] < 0.5:
p += str(int(5 - math.log(x.probs[h]) / math.log(0.0001) * 4) if x.probs[h] > 0.0001 else 0)
elif x.probs[h] >= 0.5:
p += str(int(5 + math.log(1 - x.probs[h]) / math.log(0.0001) * 4) if x.probs[h] < 0.9999 else 9)
p += '_'
elif x.probs[h] < 0.0001:
p += '-'
elif x.probs[h] > 0.9999:
p += '+'
else:
p += ALPHA[int(x.probs[h] * (len(ALPHA) - 0.0001))]
q += 'n' if len(x.received_blocks) <= h or x.received_blocks[h] is None else 'y'
o.append((h, p, q))
return o
def get_finalization_heights(n):
o = []
for x in n.agents:
o.append(x.max_finalized_height)
return o
o = []
for x in n.agents:
o.append(x.max_finalized_height)
return o
# Check how often blocks that are assigned particular probabilities of
@ -243,7 +269,7 @@ def run(steps=4000):
n = networksim.NetworkSimulator()
for i in range(NUM_VALIDATORS):
n.agents.append(Validator(i, n))
n.generate_peers()
n.generate_peers(3)
while len(all_signatures):
all_signatures.pop()
for x in future.keys():
@ -255,29 +281,37 @@ def run(steps=4000):
for i in range(steps):
n.tick()
if i % 500 == 0:
print get_opinions(n)[-60:]
minmax = 99999999999999999
for x in n.agents:
minmax = min(minmax, x.max_finalized_height - 10)
print get_opinions(n)[max(minmax, 0):]
finalized0 = [(v.max_finalized_height, v.finalized_hashes) for v in n.agents]
finalized = sorted(finalized0, key=lambda x: len(x[1]))
for j in range(len(n.agents) - 1):
for k in range(len(finalized[j][1])):
if finalized[j][1][k] is not None and finalized[j+1][1][k] is not None:
if finalized[j][1][k] != finalized[j+1][1][k]:
print finalized[j]
print finalized[j+1]
raise Exception("Finalization mismatch: %r %r" % (finalized[j][1][k], finalized[j+1][1][k]))
if CHECK_INTEGRITY:
finalized = sorted(finalized0, key=lambda x: len(x[1]))
for j in range(len(n.agents) - 1):
for k in range(len(finalized[j][1])):
if finalized[j][1][k] is not None and finalized[j+1][1][k] is not None:
if finalized[j][1][k] != finalized[j+1][1][k]:
print finalized[j]
print finalized[j+1]
raise Exception("Finalization mismatch: %r %r" % (finalized[j][1][k], finalized[j+1][1][k]))
print 'Finalized status: %r' % [x[0] for x in finalized0]
if i == 10000 and NETSPLITS:
_all = finalized0[0][1]
_pos = len([x for x in _all if x])
_neg = len([x for x in _all if not x])
print 'Finalized blocks: %r (%r positive, %r negaitve)' % (len(_all), _pos, _neg)
if i == 10000 and NETSPLITS >= 1:
print "###########################################################"
print "Knocking off 20% of the network!!!!!"
print "###########################################################"
n.knock_offline_random(NUM_VALIDATORS // 5)
if i == 20000 and NETSPLITS:
if i == 20000 and NETSPLITS >= 2:
print "###########################################################"
print "Simluating a netsplit!!!!!"
print "###########################################################"
n.generate_peers()
n.partition()
if i == 30000 and NETSPLITS:
if i == 30000 and NETSPLITS >= 1:
print "###########################################################"
print "Network health back to normal!"
print "###########################################################"