class LRU:
class LRU_Entry:
def __init__(self, oblock):
self.oblock = oblock
def __repr__(self):
return "(o={})".format(self.oblock)
def __init__(self, cache_size, **kwargs):
self.cache_size = cache_size
self.lru = DequeDict()
self.time = 0
self.pollution = Pollutionator(cache_size)
self.cache = []
def __contains__(self, oblock):
return oblock in self.lru
def addToCache(self, oblock):
x = self.LRU_Entry(oblock)
self.lru[oblock] = x
def hit(self, oblock):
x = self.lru[oblock]
self.lru[oblock] = x
def evict(self):
lru = self.lru.popFirst()
self.pollution.remove(lru.oblock)
return lru
def miss(self, oblock):
if len(self.lru) == self.cache_size:
self.evict()
self.addToCache(oblock)
def request(self, oblock):
miss = True
eviction = False
self.time += 1
if oblock in self.lru:
miss = False
self.hit(oblock)
else:
eviction = self.miss(oblock)
self.cache.append(oblock)
# Pollutionator
if miss:
self.pollution.incrementUniqueCount()
self.pollution.setUnique(oblock)
self.pollution.update(self.time)
return miss
class DLIRS:
class DLIRS_Entry:
def __init__(self, oblock, is_LIR=False, in_cache=True):
self.oblock = oblock
self.is_LIR = is_LIR
self.is_demoted = False
self.in_cache = in_cache
def __repr__(self):
return "(o={}, is_LIR={}, is_demoted={}, in_cache={})".format(
self.oblock, self.is_LIR, self.is_demoted, self.in_cache)
def __init__(self, cache_size, **kwargs):
self.cache_size = cache_size
self.hirs_ratio = 0.01
process_kwargs(self, kwargs, acceptable_kws=['hirs_ratio'])
self.hirs_limit = max(1,
int((self.cache_size * self.hirs_ratio) + 0.5))
self.lirs_limit = self.cache_size - self.hirs_limit
self.hirs_count = 0
self.lirs_count = 0
self.demoted = 0
self.nonresident = 0
# s stack, semi-split to find nonresident HIRs quickly
self.lirs = DequeDict()
self.hirs = DequeDict()
# q, the resident HIR stack
self.q = DequeDict()
self.time = 0
self.visual = Visualizinator(labels=['Q size'])
self.pollution = Pollutionator(cache_size)
def __contains__(self, oblock):
if oblock in self.lirs:
return self.lirs[oblock].in_cache
return oblock in self.q
def hitLIR(self, oblock):
lru_lir = self.lirs.first()
x = self.lirs[oblock]
self.lirs[oblock] = x
if lru_lir is x:
self.prune()
def prune(self):
while self.lirs:
x = self.lirs.first()
if x.is_LIR:
break
del self.lirs[x.oblock]
del self.hirs[x.oblock]
if not x.in_cache:
self.nonresident -= 1
def hitHIRinLIRS(self, oblock):
x = self.lirs[oblock]
in_cache = x.in_cache
x.is_LIR = True
del self.lirs[oblock]
del self.hirs[oblock]
if in_cache:
del self.q[oblock]
self.hirs_count -= 1
else:
self.adjustSize(True)
x.in_cache = True
self.nonresident -= 1
while self.lirs_count >= self.lirs_limit:
self.ejectLIR()
while self.hirs_count + self.lirs_count >= self.cache_size:
self.ejectHIR()
self.lirs[oblock] = x
self.lirs_count += 1
return not in_cache
def ejectLIR(self):
lru = self.lirs.popFirst()
self.lirs_count -= 1
lru.is_LIR = False
lru.is_demoted = True
self.demoted += 1
self.q[lru.oblock] = lru
self.hirs_count += 1
self.prune()
def ejectHIR(self):
lru = self.q.popFirst()
if lru.oblock in self.lirs:
lru.in_cache = False
self.nonresident += 1
if lru.is_demoted:
self.demoted -= 1
self.hirs_count -= 1
self.pollution.remove(lru.oblock)
def hitHIRinQ(self, oblock):
x = self.q[oblock]
if x.is_demoted:
self.adjustSize(False)
x.is_demoted = False
self.demoted -= 1
self.q[oblock] = x
self.lirs[oblock] = x
self.hirs[oblock] = x
self.limitStack()
def limitStack(self):
while self.hirs_count + self.lirs_count + self.nonresident > 2 * self.cache_size:
lru = self.hirs.popFirst()
del self.lirs[lru.oblock]
if not lru.in_cache:
self.nonresident -= 1
def miss(self, oblock):
if self.lirs_count < self.lirs_limit and self.hirs_count == 0:
x = self.DLIRS_Entry(oblock, is_LIR=True)
self.lirs[oblock] = x
self.lirs_count += 1
return
while self.hirs_count + self.lirs_count >= self.cache_size:
while self.lirs_count > self.lirs_limit:
self.ejectLIR()
self.ejectHIR()
x = self.DLIRS_Entry(oblock, is_LIR=False)
self.lirs[oblock] = x
self.hirs[oblock] = x
self.q[oblock] = x
self.hirs_count += 1
self.limitStack()
def adjustSize(self, hit_nonresident_hir):
if hit_nonresident_hir:
self.hirs_limit = min(
self.cache_size - 1, self.hirs_limit +
max(1, int((self.demoted / self.nonresident) + 0.5)))
self.lirs_limit = self.cache_size - self.hirs_limit
else:
self.lirs_limit = min(
self.cache_size - 1, self.lirs_limit +
max(1, int((self.nonresident / self.demoted) + 0.5)))
self.hirs_limit = self.cache_size - self.lirs_limit
def request(self, oblock):
miss = False
self.time += 1
if oblock in self.lirs:
x = self.lirs[oblock]
if x.is_LIR:
self.hitLIR(oblock)
else:
miss = self.hitHIRinLIRS(oblock)
elif oblock in self.q:
self.hitHIRinQ(oblock)
else:
miss = True
self.miss(oblock)
# Visualizinator
self.visual.add({'Q size': (self.time, self.hirs_limit)})
# Pollutionator
if miss:
self.pollution.incrementUniqueCount()
self.pollution.setUnique(oblock)
self.pollution.update(self.time)
return miss
def get_hir_size(self):
#print("in the dlir hir size method")
#print(len(self.q))
return len(self.q)
class ARC:
class ARC_Entry:
def __init__(self, oblock):
self.oblock = oblock
def __repr__(self):
return "({})".format(self.oblock)
def __init__(self, cache_size, **kwargs):
self.cache_size = cache_size
self.p = 0
self.T1 = DequeDict()
self.T2 = DequeDict()
self.B1 = DequeDict()
self.B2 = DequeDict()
self.time = 0
self.visual = Visualizinator(labels=['p_value'])
self.pollution = Pollutionator(self.cache_size)
def __contains__(self, oblock):
return oblock in self.T1 or oblock in self.T2
def cacheFull(self):
return len(self.T1) + len(self.T2) == self.cache_size
def addToCache(self, oblock):
x = self.ARC_Entry(oblock)
self.T1[oblock] = x
def moveToList(self, entry, arc_list):
arc_list[entry.oblock] = entry
def hit(self, oblock, arc_list):
x = arc_list[oblock]
del arc_list[oblock]
self.moveToList(x, self.T2)
def evictFromList(self, arc_list):
assert (len(arc_list) > 0)
return arc_list.popFirst()
def evict(self):
len_L1 = len(self.T1) + len(self.B1)
len_L2 = len(self.T2) + len(self.B2)
if len_L1 == self.cache_size:
if len(self.T1) < self.cache_size:
hist_evict = self.evictFromList(self.B1)
evicted = self.replace()
else:
evicted = self.evictFromList(self.T1)
elif len_L1 < self.cache_size and len_L1 + len_L2 >= self.cache_size:
if len_L1 + len_L2 == 2 * self.cache_size:
self.evictFromList(self.B2)
evicted = self.replace()
self.pollution.remove(evicted.oblock)
return evicted
def replace(self, x_in_B2=False):
if len(self.T1) > 0 and ((x_in_B2 and len(self.T1) == self.p)
or len(self.T1) > self.p):
evicted = self.evictFromList(self.T1)
self.moveToList(evicted, self.B1)
else:
evicted = self.evictFromList(self.T2)
self.moveToList(evicted, self.B2)
return evicted
def missInHistory(self, oblock, history):
x = history[oblock]
x_in_B2 = oblock in self.B2
del history[oblock]
evicted = self.replace(x_in_B2)
self.pollution.remove(evicted.oblock)
self.moveToList(x, self.T2)
def miss(self, oblock):
if oblock in self.B1:
self.p = min(self.p + max(1,
len(self.B2) // len(self.B1)),
self.cache_size)
self.missInHistory(oblock, self.B1)
elif oblock in self.B2:
self.p = max(self.p - max(1, len(self.B1) // len(self.B2)), 0)
self.missInHistory(oblock, self.B2)
else:
if self.cacheFull():
self.evict()
self.addToCache(oblock)
def request(self, oblock):
miss = True
self.time += 1
if oblock in self:
miss = False
if oblock in self.T1:
self.hit(oblock, self.T1)
else:
self.hit(oblock, self.T2)
else:
self.miss(oblock)
# Visualizinator
self.visual.add({'p_value': (self.time, self.p)})
# Pollutionator
if miss:
self.pollution.incrementUniqueCount()
self.pollution.setUnique(oblock)
self.pollution.update(self.time)
return miss
def get_p(self):
return float(self.p / self.cache_size)
class ALeCaR6:
######################
## INTERNAL CLASSES ##
######################
# Entry to track the page information
class ALeCaR6_Entry:
def __init__(self, oblock, freq=1, time=0):
self.oblock = oblock
self.freq = freq
self.time = time
self.evicted_time = None
# Minimal comparitors needed for HeapDict
def __lt__(self, other):
if self.freq == other.freq:
return self.time > other.time
return self.freq < other.freq
# Useful for debugging
def __repr__(self):
return "(o={}, f={}, t={})".format(self.oblock, self.freq,
self.time)
# Adaptive learning rate of ALeCaR6
# TODO consider an internal time instead of taking time as a parameter
class ALeCaR6_Learning_Rate:
# kwargs: We're using keyword arguments so that they can be passed down as
# needed. We can filter through the keywords for ones we want,
# ignoring those we don't use. We then update our instance with
# the passed values for the given keys after the default
# initializations and before the possibly passed keys are used in
# a way that cannot be taken back, such as setting the learning rate
# reset point, which is reliant on the starting learning_rate
def __init__(self, period_length, **kwargs):
self.learning_rate = np.sqrt((2.0 * np.log(2)) / period_length)
process_kwargs(self, kwargs, acceptable_kws=['learning_rate'])
self.learning_rate_reset = min(max(self.learning_rate, 0.001), 1)
self.learning_rate_curr = self.learning_rate
self.learning_rate_prev = 0.0
self.learning_rates = []
self.period_len = period_length
self.hitrate = 0
self.hitrate_prev = 0.0
self.hitrate_diff_prev = 0.0
self.hitrate_nega_count = 0
self.hitrate_zero_count = 0
# Used to use the learning_rate value to multiply without
# having to use self.learning_rate.learning_rate, which can
# impact readability
def __mul__(self, other):
return self.learning_rate * other
# Update the adaptive learning rate when we've reached the end of a period
def update(self, time):
if time % self.period_len == 0:
# TODO: remove float() when using Python3
hitrate_curr = round(self.hitrate / float(self.period_len), 3)
hitrate_diff = round(hitrate_curr - self.hitrate_prev, 3)
delta_LR = round(self.learning_rate_curr, 3) - round(
self.learning_rate_prev, 3)
delta, delta_HR = self.updateInDeltaDirection(
delta_LR, hitrate_diff)
if delta > 0:
self.learning_rate = min(
self.learning_rate +
abs(self.learning_rate * delta_LR), 1)
self.hitrate_nega_count = 0
self.hitrate_zero_count = 0
elif delta < 0:
self.learning_rate = max(
self.learning_rate -
abs(self.learning_rate * delta_LR), 0.001)
self.hitrate_nega_count = 0
self.hitrate_zero_count = 0
elif delta == 0 and hitrate_diff <= 0:
if (hitrate_curr <= 0 and hitrate_diff == 0):
self.hitrate_zero_count += 1
if hitrate_diff < 0:
self.hitrate_nega_count += 1
self.hitrate_zero_count += 1
if self.hitrate_zero_count >= 10:
self.learning_rate = self.learning_rate_reset
self.hitrate_zero_count = 0
elif hitrate_diff < 0:
if self.hitrate_nega_count >= 10:
self.learning_rate = self.learning_rate_reset
self.hitrate_nega_count = 0
else:
self.updateInRandomDirection()
self.learning_rate_prev = self.learning_rate_curr
self.learning_rate_curr = self.learning_rate
self.hitrate_prev = hitrate_curr
self.hitrate_diff_prev = hitrate_diff
self.hitrate = 0
# TODO check that this is necessary and shouldn't be moved to
# the Visualizinator
self.learning_rates.append(self.learning_rate)
# Update the learning rate according to the change in learning_rate and hitrate
def updateInDeltaDirection(self, learning_rate_diff, hitrate_diff):
delta = learning_rate_diff * hitrate_diff
# Get delta = 1 if learning_rate_diff and hitrate_diff are both positive or negative
# Get delta =-1 if learning_rate_diff and hitrate_diff have different signs
# Get delta = 0 if either learning_rate_diff or hitrate_diff == 0
delta = int(delta / abs(delta)) if delta != 0 else 0
delta_HR = 0 if delta == 0 and learning_rate_diff != 0 else 1
return delta, delta_HR
# Update the learning rate in a random direction or correct it from extremes
def updateInRandomDirection(self):
if self.learning_rate >= 1:
self.learning_rate = 0.9
elif self.learning_rate <= 0.001:
self.learning_rate = 0.005
elif np.random.choice(['Increase', 'Decrease']) == 'Increase':
self.learning_rate = min(self.learning_rate * 1.25, 1)
else:
self.learning_rate = max(self.learning_rate * 0.75, 0.001)
# kwargs: We're using keyword arguments so that they can be passed down as
# needed. We can filter through the keywords for ones we want,
# ignoring those we don't use. We then update our instance with
# the passed values for the given keys after the default
# initializations and before the possibly passed keys are used in
# a way that cannot be taken back, such as setting the weights(W)
# Please note that cache_size is a required argument and not
# optional like all the kwargs are
def __init__(self, cache_size, **kwargs):
# Randomness and Time
np.random.seed(123)
self.time = 0
# Cache
self.cache_size = cache_size
self.lru = DequeDict()
self.lfu = HeapDict()
# Histories
self.history_size = cache_size // 2
self.lru_hist = DequeDict()
self.lfu_hist = DequeDict()
# Decision Weights Initilized
self.initial_weight = 0.5
# Learning Rate
self.learning_rate = self.ALeCaR6_Learning_Rate(cache_size, **kwargs)
# Apply values in kwargs, before any accepted_kws members
# are prerequisites
process_kwargs(self,
kwargs,
acceptable_kws=['initial_weight', 'history_size'])
# Decision Weights
self.W = np.array([self.initial_weight, 1 - self.initial_weight],
dtype=np.float32)
# Visualize
self.visual = Visualizinator(
labels=['W_lru-ALeCaR6', 'W_lfu-ALeCaR6', 'hit-rate'],
windowed_labels=['hit-rate'],
window_size=cache_size)
# Pollution
self.pollution = Pollutionator(cache_size)
# True if oblock is in cache (which LRU can represent)
def __contains__(self, oblock):
return oblock in self.lru
# Add Entry to cache with given frequency
def addToCache(self, oblock, freq):
x = self.ALeCaR6_Entry(oblock, freq, self.time)
self.lru[oblock] = x
self.lfu[oblock] = x
# Add Entry to history dictated by policy
# policy: 0, Add Entry to LRU History
# 1, Add Entry to LFU History
# -1, Do not add Entry to any History
def addToHistory(self, x, policy):
# Use reference to policy_history to reduce redundant code
policy_history = None
if policy == 0:
policy_history = self.lru_hist
elif policy == 1:
policy_history = self.lfu_hist
elif policy == -1:
return
# Evict from history is it is full
if len(policy_history) == self.history_size:
evicted = self.getLRU(policy_history)
del policy_history[evicted.oblock]
policy_history[x.oblock] = x
# Get the LRU item in the given DequeDict
# NOTE: DequeDict can be: lru, lru_hist, or lfu_hist
# NOTE: does *NOT* remove the LRU Entry from given DequeDict
def getLRU(self, dequeDict):
return dequeDict.first()
# Get the LFU min item in the LFU (HeapDict)
# NOTE: does *NOT* remove the LFU Entry from LFU
def getHeapMin(self):
return self.lfu.min()
# Get the random eviction choice based on current weights
def getChoice(self):
return 0 if np.random.rand() < self.W[0] else 1
# Evict an entry
def evict(self):
lru = self.getLRU(self.lru)
lfu = self.getHeapMin()
evicted = lru
policy = self.getChoice()
# Since we're using Entry references, we use is to check
# that the LRU and LFU Entries are the same Entry
if lru is lfu:
evicted, policy = lru, -1
elif policy == 0:
evicted = lru
else:
evicted = lfu
del self.lru[evicted.oblock]
del self.lfu[evicted.oblock]
evicted.evicted_time = self.time
self.pollution.remove(evicted.oblock)
self.addToHistory(evicted, policy)
return evicted, policy
# Cache Hit
def hit(self, oblock):
x = self.lru[oblock]
x.time = self.time
self.lru[oblock] = x
x.freq += 1
self.lfu[oblock] = x
# Adjust the weights based on the given rewards for LRU and LFU
def adjustWeights(self, rewardLRU, rewardLFU):
reward = np.array([rewardLRU, rewardLFU], dtype=np.float32)
self.W = self.W * np.exp(self.learning_rate * reward)
self.W = self.W / np.sum(self.W)
if self.W[0] >= 0.99:
self.W = np.array([0.99, 0.01], dtype=np.float32)
elif self.W[1] >= 0.99:
self.W = np.array([0.01, 0.99], dtype=np.float32)
# Cache Miss
def miss(self, oblock):
freq = 1
if oblock in self.lru_hist:
entry = self.lru_hist[oblock]
freq = entry.freq + 1
del self.lru_hist[oblock]
self.adjustWeights(-1, 0)
elif oblock in self.lfu_hist:
entry = self.lfu_hist[oblock]
freq = entry.freq + 1
del self.lfu_hist[oblock]
self.adjustWeights(0, -1)
# If the cache is full, evict
if len(self.lru) == self.cache_size:
evicted, policy = self.evict()
self.addToCache(oblock, freq)
# Process and access request for the given oblock
def request(self, oblock):
miss = True
self.time += 1
self.visual.add({
'W_lru-ALeCaR6': (self.time, self.W[0]),
'W_lfu-ALeCaR6': (self.time, self.W[1])
})
self.learning_rate.update(self.time)
if oblock in self:
miss = False
self.hit(oblock)
else:
self.miss(oblock)
# Windowed
self.visual.addWindow({'hit-rate': 0 if miss else 1}, self.time)
# Learning Rate
if not miss:
self.learning_rate.hitrate += 1
# Pollution
if miss:
self.pollution.incrementUniqueCount()
self.pollution.setUnique(oblock)
self.pollution.update(self.time)
return miss
class Cacheus:
######################
## INTERNAL CLASSES ##
######################
# Entry to track the page information
class Cacheus_Entry:
# TODO is_new logic to is not demoted
def __init__(self, oblock, freq=1, time=0, is_new=True):
self.oblock = oblock
self.freq = freq
self.time = time
self.evicted_time = None
self.is_demoted = False
self.is_new = is_new
# Minimal comparitors needed for HeapDict
def __lt__(self, other):
if self.freq == other.freq:
return self.time > other.time
return self.freq < other.freq
# Useful for debugging
def __repr__(self):
return "(o={}, f={}, t={})".format(self.oblock, self.freq,
self.time)
# Adaptive learning rate of Cacheus
# TODO consider an internal time instead of taking time as a parameter
class Cacheus_Learning_Rate:
# kwargs: We're using keyword arguments so that they can be passed down as
# needed. We can filter through the keywords for ones we want,
# ignoring those we don't use. We then update our instance with
# the passed values for the given keys after the default
# initializations and before the possibly passed keys are used in
# a way that cannot be taken back, such as setting the learning rate
# reset point, which is reliant on the starting learning_rate
def __init__(self, period_length, **kwargs):
self.learning_rate = np.sqrt((2.0 * np.log(2)) / period_length)
process_kwargs(self, kwargs, acceptable_kws=['learning_rate'])
self.learning_rate_reset = min(max(self.learning_rate, 0.001), 1)
self.learning_rate_curr = self.learning_rate
self.learning_rate_prev = 0.0
self.learning_rates = []
self.period_len = period_length
self.hitrate = 0
self.hitrate_prev = 0.0
self.hitrate_diff_prev = 0.0
self.hitrate_zero_count = 0
self.hitrate_nega_count = 0
# Used to use the learning_rate value to multiply without
# having to use self.learning_rate.learning_rate, which can
# impact readability
def __mul__(self, other):
return self.learning_rate * other
# Update the adaptive learning rate when we've reached the end of a period
def update(self, time):
if time % self.period_len == 0:
# TODO: remove float() when using Python3
hitrate_curr = round(self.hitrate / self.period_len, 3)
hitrate_diff = round(hitrate_curr - self.hitrate_prev, 3)
delta_LR = round(self.learning_rate_curr, 3) - round(
self.learning_rate_prev, 3)
delta, delta_HR = self.updateInDeltaDirection(
delta_LR, hitrate_diff)
if delta > 0:
self.learning_rate = min(
self.learning_rate +
abs(self.learning_rate * delta_LR), 1)
self.hitrate_nega_count = 0
self.hitrate_zero_count = 0
elif delta < 0:
self.learning_rate = max(
self.learning_rate -
abs(self.learning_rate * delta_LR), 0.001)
self.hitrate_nega_count = 0
self.hitrate_zero_count = 0
elif delta == 0 and hitrate_diff <= 0:
if (hitrate_curr <= 0 and hitrate_diff == 0):
self.hitrate_zero_count += 1
if hitrate_diff < 0:
self.hitrate_nega_count += 1
self.hitrate_zero_count += 1
if self.hitrate_zero_count >= 10:
self.learning_rate = self.learning_rate_reset
self.hitrate_zero_count = 0
elif hitrate_diff < 0:
if self.hitrate_nega_count >= 10:
self.learning_rate = self.learning_rate_reset
self.hitrate_nega_count = 0
else:
self.updateInRandomDirection()
self.learning_rate_prev = self.learning_rate_curr
self.learning_rate_curr = self.learning_rate
self.hitrate_prev = hitrate_curr
self.hitrate_diff_prev = hitrate_diff
self.hitrate = 0
# TODO check that this is necessary and shouldn't be moved to
# the Visualizinator
self.learning_rates.append(self.learning_rate)
# Update the learning rate according to the change in learning_rate and hitrate
def updateInDeltaDirection(self, learning_rate_diff, hitrate_diff):
delta = learning_rate_diff * hitrate_diff
# Get delta = 1 if learning_rate_diff and hitrate_diff are both positive or negative
# Get delta =-1 if learning_rate_diff and hitrate_diff have different signs
# Get delta = 0 if either learning_rate_diff or hitrate_diff == 0
delta = int(delta / abs(delta)) if delta != 0 else 0
delta_HR = 0 if delta == 0 and learning_rate_diff != 0 else 1
return delta, delta_HR
# Update the learning rate in a random direction or correct it from extremes
def updateInRandomDirection(self):
if self.learning_rate >= 1:
self.learning_rate = 0.9
elif self.learning_rate <= 0.001:
self.learning_rate = 0.005
elif np.random.choice(['Increase', 'Decrease']) == 'Increase':
self.learning_rate = min(self.learning_rate * 1.25, 1)
else:
self.learning_rate = max(self.learning_rate * 0.75, 0.001)
# kwargs: We're using keyword arguments so that they can be passed down as
# needed. We can filter through the keywords for ones we want,
# ignoring those we don't use. We then update our instance with
# the passed values for the given keys after the default
# initializations and before the possibly passed keys are used in
# a way that cannot be taken back, such as setting the weights(W)
# Please note that cache_size is a required argument and not
# optional like all the kwargs are
def __init__(self, cache_size, **kwargs):
# Randomness and Time
np.random.seed(123)
self.time = 0
# Cache
self.cache_size = cache_size
#two stacks for the cache(s and q) to mark demoted items faster
self.s = DequeDict()
self.q = DequeDict()
#lfu heap
self.lfu = HeapDict()
# Histories
self.history_size = cache_size // 2
self.lru_hist = DequeDict()
self.lfu_hist = DequeDict()
# Decision Weights Initilized
self.initial_weight = 0.5
# Learning Rate
self.learning_rate = self.Cacheus_Learning_Rate(cache_size, **kwargs)
process_kwargs(self,
kwargs,
acceptable_kws=['initial_weight', 'history_size'])
# Decision Weights
self.W = np.array([self.initial_weight, 1 - self.initial_weight],
dtype=np.float32)
# Variables
hirsRatio = 0.01
self.q_limit = max(1, int((hirsRatio * self.cache_size) + 0.5))
self.s_limit = self.cache_size - self.q_limit
self.q_size = 0
self.s_size = 0
self.dem_count = 0
self.nor_count = 0
self.q_sizes = []
# Visualize
self.visual = Visualizinator(
labels=['W_lru-Cacheus', 'W_lfu-Cacheus', 'q_size'])
# Pollution
self.pollution = Pollutionator(cache_size)
# True if oblock is in cache (which LRU can represent)
def __contains__(self, oblock):
return (oblock in self.s or oblock in self.q)
#Hit in MRU portion of the cache
def hitinS(self, oblock):
x = self.s[oblock]
x.time = self.time
self.s[oblock] = x
x.freq += 1
self.lfu[oblock] = x
#Hit in LRU portion of the cache
def hitinQ(self, oblock):
x = self.q[oblock]
x.time = self.time
x.freq += 1
self.lfu[oblock] = x
if x.is_demoted:
self.adjustSize(True)
x.is_demoted = False
self.dem_count -= 1
del self.q[x.oblock]
self.q_size -= 1
if self.s_size >= self.s_limit:
y = self.s.popFirst()
y.is_demoted = True
self.dem_count += 1
self.s_size -= 1
self.q[y.oblock] = y
self.q_size += 1
self.s[x.oblock] = x
self.s_size += 1
# Add Entry to S with given frequency
def addToS(self, oblock, freq, isNew=True):
x = self.Cacheus_Entry(oblock, freq, self.time, isNew)
self.s[oblock] = x
self.lfu[oblock] = x
self.s_size += 1
def addToQ(self, oblock, freq, isNew=True):
x = self.Cacheus_Entry(oblock, freq, self.time, isNew)
self.q[oblock] = x
self.lfu[oblock] = x
self.q_size += 1
# Add Entry to history dictated by policy
# policy: 0, Add Entry to LRU History
# 1, Add Entry to LFU History
# -1, Do not add Entry to any History
def addToHistory(self, x, policy):
# Use reference to policy_history to reduce redundant code
policy_history = None
if policy == 0:
policy_history = self.lru_hist
if x.is_new:
self.nor_count += 1
elif policy == 1:
policy_history = self.lfu_hist
elif policy == -1:
return
# Evict from history is it is full
if len(policy_history) == self.history_size:
evicted = self.getLRU(policy_history)
del policy_history[evicted.oblock]
policy_history[x.oblock] = x
# Get the LRU item in the given DequeDict
# NOTE: DequeDict can be: lru, lru_hist, or lfu_hist
# NOTE: does *NOT* remove the LRU Entry from given DequeDict
def getLRU(self, dequeDict):
return dequeDict.first()
# Get the LFU min item in the LFU (HeapDict)
# NOTE: does *NOT* remove the LFU Entry from LFU
def getHeapMin(self):
return self.lfu.min()
# Get the random eviction choice based on current weights
def getChoice(self):
return 0 if np.random.rand() < self.W[0] else 1
# Evict an entry
def evict(self):
lru = self.getLRU(self.q)
lfu = self.getHeapMin()
evicted = lru
policy = self.getChoice()
# Since we're using Entry references, we use is to check
# that the LRU and LFU Entries are the same Entry
if lru is lfu:
evicted, policy = lru, -1
elif policy == 0:
evicted = lru
del self.q[evicted.oblock]
self.q_size -= 1
elif policy == 1:
evicted = lfu
if evicted.oblock in self.s:
del self.s[evicted.oblock]
self.s_size -= 1
#self.q_size += 1
elif evicted.oblock in self.q:
del self.q[evicted.oblock]
self.q_size -= 1
if policy == -1:
del self.q[evicted.oblock]
self.q_size -= 1
del self.lfu[evicted.oblock]
evicted.evicted_time = self.time
self.pollution.remove(evicted.oblock)
self.addToHistory(evicted, policy)
return evicted, policy
# Adjust the weights based on the given rewards for LRU and LFU
def adjustWeights(self, rewardLRU, rewardLFU):
reward = np.array([rewardLRU, rewardLFU], dtype=np.float32)
self.W = self.W * np.exp(self.learning_rate * reward)
self.W = self.W / np.sum(self.W)
if self.W[0] >= 0.99:
self.W = np.array([0.99, 0.01], dtype=np.float32)
elif self.W[1] >= 0.99:
self.W = np.array([0.01, 0.99], dtype=np.float32)
def adjustSize(self, hit_in_Q):
# self.dem_count = 1 if self.dem_count == 0
# self.nor_count = 1 if self.nor_count == 0
if hit_in_Q:
self.s_limit = min(
self.cache_size - 1, self.s_limit +
max(1, int((self.nor_count / (self.dem_count + 2)) + 0.5)))
self.q_limit = self.cache_size - self.s_limit
else:
self.q_limit = min(
self.cache_size - 1, self.q_limit +
max(1, int((self.dem_count / (self.nor_count + 2)) + 0.5)))
self.s_limit = self.cache_size - self.q_limit
def hitinLRUHist(self, oblock):
entry = self.lru_hist[oblock]
freq = entry.freq + 1
del self.lru_hist[oblock]
if entry.is_new:
self.nor_count -= 1
entry.is_new = False
self.adjustSize(False)
self.adjustWeights(-1, 0)
if (self.s_size + self.q_size) >= self.cache_size:
evicted, policy = self.evict()
self.addToS(entry.oblock, entry.freq, isNew=False)
self.limitStack()
def hitinLFUHist(self, oblock):
entry = self.lfu_hist[oblock]
freq = entry.freq + 1
del self.lfu_hist[oblock]
self.adjustWeights(0, -1)
if (self.s_size + self.q_size) >= self.cache_size:
evicted, policy = self.evict()
self.addToS(entry.oblock, entry.freq, isNew=False)
self.limitStack()
def limitStack(self):
while self.s_size >= self.s_limit:
#print("entering to mark demoted in limited stack")
demoted = self.s.popFirst()
self.s_size -= 1
demoted.is_demoted = True
self.dem_count += 1
self.q[demoted.oblock] = demoted
self.q_size += 1
# Cache Miss
def miss(self, oblock):
freq = 1
if self.s_size < self.s_limit and self.q_size == 0:
self.addToS(oblock, freq, isNew=False)
elif self.s_size + self.q_size < self.cache_size and self.q_size < self.q_limit:
self.addToQ(oblock, freq, isNew=False)
else:
# NOTE: does this belong before the previous if-else block?
# TODO Eviction of multiple blocks in Q ?
# If the cache is full, evict
if (self.s_size + self.q_size) >= self.cache_size:
evicted, policy = self.evict()
# NOTE: it's possible that these should be in an else instead
#Filling up the cache
self.addToQ(oblock, freq, isNew=True)
self.limitStack()
# Process and access request for the given oblock
def request(self, oblock):
miss = False
#print("Request: {}\n".format(oblock))
self.time += 1
self.visual.add({
'W_lru-Cacheus': (self.time, self.W[0]),
'W_lfu-Cacheus': (self.time, self.W[1]),
'q_size': (self.time, self.q_size)
})
#if self.time % (self.cache_size//2) == 0:
#print("q size", self.q_size)
#print("demoted count", self.dem_count)
#print("nor count", self.nor_count)
self.learning_rate.update(self.time)
if oblock in self.s:
#print("hit in s")
self.hitinS(oblock)
elif oblock in self.q:
#print("hit in q")
self.hitinQ(oblock)
elif oblock in self.lru_hist:
#print("hit in lru_hits")
miss = True
self.hitinLRUHist(oblock)
elif oblock in self.lfu_hist:
#print("hit in lfu_hist")
miss = True
self.hitinLFUHist(oblock)
else:
#print("miss")
miss = True
self.miss(oblock)
# Learning Rate
if not miss:
self.learning_rate.hitrate += 1
# Pollution
if miss:
self.pollution.incrementUniqueCount()
self.pollution.setUnique(oblock)
if self.time % self.cache_size == 0:
self.pollution.update(self.time)
return miss
def getQsize(self):
x, y = zip(*self.visual.get('q_size'))
return y
def get_w_lru(self):
return self.W[0]
def get_learning_rate(self):
return self.learning_rate.learning_rate_curr
def get_q(self):
return self.q_size
class LeCaR:
######################
## INTERNAL CLASSES ##
######################
# Entry to track the page information
class LeCaR_Entry:
def __init__(self, oblock, freq=1, time=0):
self.oblock = oblock
self.freq = freq
self.time = time
self.evicted_time = None
# Minimal comparitors needed for HeapDict
def __lt__(self, other):
if self.freq == other.freq:
return self.oblock < other.oblock
return self.freq < other.freq
# Useful for debugging
def __repr__(self):
return "(o={}, f={}, t={})".format(self.oblock, self.freq,
self.time)
# kwargs: We're using keyword arguments so that they can be passed down as
# needed. We can filter through the keywords for ones we want,
# ignoring those we don't use. We then update our instance with
# the passed values for the given keys after the default
# initializations and before the possibly passed keys are used in
# a way that cannot be taken back, such as setting the weights(W)
# Please note that cache_size is a required argument and not
# optional like all the kwargs are
def __init__(self, cache_size, **kwargs):
# Randomness and Time
np.random.seed(123)
self.time = 0
# Cache
self.cache_size = cache_size
self.lru = DequeDict()
self.lfu = HeapDict()
# Histories
self.history_size = cache_size // 2
self.lru_hist = DequeDict()
self.lfu_hist = DequeDict()
# Decision Weights Initilized
self.initial_weight = 0.5
# Fixed Learning Rate
self.learning_rate = 0.45
# Fixed Discount Rate
self.discount_rate = 0.005**(1 / self.cache_size)
# Apply values in kwargs, before any acceptable_kws
# members are prerequisites
process_kwargs(
self,
kwargs,
acceptable_kws=['learning_rate', 'initial_weight', 'history_size'])
# Decision Weights
self.W = np.array([self.initial_weight, 1 - self.initial_weight],
dtype=np.float32)
# Visualize
self.visual = Visualizinator(
labels=['W_lru-LeCaR', 'W_lfu-LeCaR', 'hit-rate'],
windowed_labels=['hit-rate'],
window_size=cache_size)
# Pollution
self.pollution = Pollutionator(cache_size)
# True if oblock is in cache (which LRU can represent)
def __contains__(self, oblock):
return oblock in self.lru
# Add Entry to cache with given frequency
def addToCache(self, oblock, freq):
x = self.LeCaR_Entry(oblock, freq, self.time)
self.lru[oblock] = x
self.lfu[oblock] = x
# Add Entry to history dictated by policy
# policy: 0, Add Entry to LRU History
# 1, Add Entry to LFU History
# -1, Do not add Entry to any History
def addToHistory(self, x, policy):
# Use reference to policy_history to reduce redundant code
policy_history = None
if policy == 0:
policy_history = self.lru_hist
elif policy == 1:
policy_history = self.lfu_hist
elif policy == -1:
return
# Evict from history is it is full
if len(policy_history) == self.history_size:
evicted = self.getLRU(policy_history)
del policy_history[evicted.oblock]
policy_history[x.oblock] = x
# Get the LRU item in the given DequeDict
# NOTE: DequeDict can be: lru, lru_hist, or lfu_hist
# NOTE: does *NOT* remove the LRU Entry from given DequeDict
def getLRU(self, dequeDict):
return dequeDict.first()
# Get the LFU min item in the LFU (HeapDict)
# NOTE: does *NOT* remove the LFU Entry from LFU
def getHeapMin(self):
return self.lfu.min()
# Get the random eviction choice based on current weights
def getChoice(self):
return 0 if np.random.rand() < self.W[0] else 1
# Evict an entry
def evict(self):
lru = self.getLRU(self.lru)
lfu = self.getHeapMin()
evicted = lru
policy = self.getChoice()
# Since we're using Entry references, we use is to check
# that the LRU and LFU Entries are the same Entry
if lru is lfu:
evicted, policy = lru, -1
elif policy == 0:
evicted = lru
else:
evicted = lfu
del self.lru[evicted.oblock]
del self.lfu[evicted.oblock]
evicted.evicted_time = self.time
self.pollution.remove(evicted.oblock)
self.addToHistory(evicted, policy)
return evicted, policy
# Cache Hit
def hit(self, oblock):
x = self.lru[oblock]
x.time = self.time
self.lru[oblock] = x
x.freq += 1
self.lfu[oblock] = x
# Adjust the weights based on the given rewards for LRU and LFU
def adjustWeights(self, rewardLRU, rewardLFU):
reward = np.array([rewardLRU, rewardLFU], dtype=np.float32)
self.W = self.W * np.exp(self.learning_rate * reward)
self.W = self.W / np.sum(self.W)
if self.W[0] >= 0.99:
self.W = np.array([0.99, 0.01], dtype=np.float32)
elif self.W[1] >= 0.99:
self.W = np.array([0.01, 0.99], dtype=np.float32)
# Cache Miss
def miss(self, oblock):
freq = 1
if oblock in self.lru_hist:
entry = self.lru_hist[oblock]
freq = entry.freq + 1
del self.lru_hist[oblock]
reward_lru = -(self.discount_rate
**(self.time - entry.evicted_time))
self.adjustWeights(reward_lru, 0)
elif oblock in self.lfu_hist:
entry = self.lfu_hist[oblock]
freq = entry.freq + 1
del self.lfu_hist[oblock]
reward_lfu = -(self.discount_rate
**(self.time - entry.evicted_time))
self.adjustWeights(0, reward_lfu)
# If the cache is full, evict
if len(self.lru) == self.cache_size:
evicted, policy = self.evict()
self.addToCache(oblock, freq)
# Process and access request for the given oblock
def request(self, oblock):
miss = True
self.time += 1
self.visual.add({
'W_lru-LeCaR': (self.time, self.W[0]),
'W_lfu-LeCaR': (self.time, self.W[1])
})
if oblock in self:
miss = False
self.hit(oblock)
else:
self.miss(oblock)
# Windowed
self.visual.addWindow({'hit-rate': 0 if miss else 1}, self.time)
# Pollution
if miss:
self.pollution.incrementUniqueCount()
self.pollution.setUnique(oblock)
if self.time % self.cache_size == 0:
self.pollution.update(self.time)
return miss
def get_w_lru(self):
#print("in get w lru method")
#print(self.w[0])
return self.W[0]
class ARCALeCaR(ALeCaR6):
class ARC(ARC):
def get(self, oblock):
if oblock in self.T1:
return self.T1[oblock]
if oblock in self.T2:
return self.T2[oblock]
if oblock in self.B1:
return self.B1[oblock]
if oblock in self.B2:
return self.B2[oblock]
return None
def replaceSafe(self):
# getting rid of x_in_B2 as that's never a concern.
# removed the logic related to x_in_B2 as well
if len(self.T1) > self.p:
return self.T1.first()
else:
return self.T2.first()
def nextVictim(self):
len_L1 = len(self.T1) + len(self.B1)
len_L2 = len(self.T2) + len(self.B2)
if len_L1 >= self.cache_size:
if len(self.T1) < self.cache_size:
return self.replaceSafe()
else:
return self.T1.first()
elif len_L1 < self.cache_size and len_L1 + len_L2 >= self.cache_size:
return self.replaceSafe()
def evictThis(self, oblock, put_in_history=True):
if put_in_history:
next_victim = self.nextVictim().oblock
if oblock == next_victim:
evicted = self.evict()
assert (evicted == next_victim)
else:
victim = self.get(oblock)
if oblock in self.T1:
if len(self.B1) + len(self.B2) == self.cache_size:
if len(self.B1) == 0:
self.B2.popFirst()
else:
self.B1.popFirst()
del self.T1[oblock]
self.B1[oblock] = victim
else:
if len(self.B1) + len(self.B2) == self.cache_size:
if len(self.B2) == 0:
self.B1.popFirst()
else:
self.B2.popFirst()
del self.T2[oblock]
self.B2[oblock] = victim
else:
if oblock in self.T1:
del self.T1[oblock]
else:
del self.T2[oblock]
def missInHistory(self, oblock, history):
x = history[oblock]
x_in_B2 = oblock in self.B2
del history[oblock]
if len(self.T1) + len(self.T2) == self.cache_size:
evicted = self.replace(x_in_B2)
self.pollution.remove(evicted.oblock)
self.moveToList(x, self.T2)
class LFU(LFU):
def get(self, oblock):
return self.lfu[oblock]
def nextVictim(self):
return self.lfu.min()
def evictThis(self, oblock):
del self.lfu[oblock]
def request(self, oblock, freq=None):
miss = super().request(oblock)
if freq != None:
assert (isinstance(freq, int))
x = self.lfu[oblock]
del self.lfu[oblock]
x.freq = freq
self.lfu[oblock] = x
return miss
class ARCALeCaR_Entry(ALeCaR6.ALeCaR6_Entry):
pass
class ARCALeCaR_Learning_Rate(ALeCaR6.ALeCaR6_Learning_Rate):
pass
def __init__(self, cache_size, **kwargs):
np.random.seed(123)
self.time = 0
self.cache_size = cache_size
kwargs_arc = {}
kwargs_lfu = {}
if 'arc' in kwargs:
kwargs_arc = kwargs['arc']
if 'lfu' in kwargs:
kwargs_lfu = kwargs['lfu']
self.arc = self.ARC(cache_size, **kwargs_arc)
self.lfu = self.LFU(cache_size, **kwargs_lfu)
self.history_size = cache_size
self.history = DequeDict()
self.initial_weight = 0.5
self.learning_rate = self.ARCALeCaR_Learning_Rate(cache_size, **kwargs)
process_kwargs(self,
kwargs,
acceptable_kws=['initial_weight', 'history_size'])
self.W = np.array([self.initial_weight, 1 - self.initial_weight],
dtype=np.float32)
self.visual = Visualizinator(labels=['W_arc', 'W_lfu', 'hit-rate'],
windowed_labels=['hit-rate'],
window_size=cache_size,
**kwargs)
self.pollution = Pollutionator(cache_size, **kwargs)
def __contains__(self, oblock):
return oblock in self.lfu
def cacheFull(self):
return self.lfu.cacheFull()
def addToCache(self, oblock, freq):
self.arc.request(oblock)
self.lfu.request(oblock, freq=freq)
def addToHistory(self, x, policy):
policy_history = None
if policy == 0:
policy_history = "ARC"
elif policy == 1:
policy_history = "LFU"
elif policy == -1:
return False
# prune history for lazy removal to match ARC's history
if len(self.history) == 2 * self.history_size:
history_oblocks = [meta.oblock for meta in self.history]
for oblock in history_oblocks:
if not (oblock in self.arc.B1 or oblock in self.arc.B2):
del self.history[oblock]
x.evicted_me = policy_history
self.history[x.oblock] = x
return True
def evict(self):
arc = self.arc.nextVictim()
lfu = self.lfu.nextVictim()
assert (arc != None)
assert (lfu != None)
evicted = arc
policy = self.getChoice()
if arc.oblock == lfu.oblock:
evicted, policy = arc, -1
elif policy == 0:
evicted = arc
else:
evicted = lfu
# save info to meta ARCLeCaREntry for history
meta = self.ARCALeCaR_Entry(evicted.oblock, time=self.time)
# arc data for meta
# Not really any that matters. All of that is in ARC
# lfu data for meta
meta.freq = self.lfu.get(evicted.oblock).freq
put_in_history = self.addToHistory(meta, policy)
# evict from both
self.arc.evictThis(evicted.oblock, put_in_history=put_in_history)
self.lfu.evictThis(evicted.oblock)
self.pollution.remove(evicted.oblock)
return meta.oblock, policy
def hit(self, oblock):
self.arc.request(oblock)
self.lfu.request(oblock)
# NOTE: adjustWeights has parameters rewardLRU and rewardLFU but technically
# the naming didn't matter and we can use as it is
def miss(self, oblock):
freq = None
evicted = None
if oblock in self.history:
# history based on N in ARC's history
# we can do get since we missed so this should be checking
# B1 or B2 only now
if self.arc.get(oblock) != None:
meta = self.history[oblock]
freq = meta.freq + 1
if meta.evicted_me == "ARC":
self.adjustWeights(-1, 0)
else:
self.adjustWeights(0, -1)
del self.history[oblock]
if len(self.lfu.lfu) == self.cache_size:
evicted, policy = self.evict()
self.addToCache(oblock, freq)
return evicted
def request(self, oblock):
miss = True
evicted = None
op = CacheOp.INSERT
self.time += 1
self.visual.add({
'W_arc': (self.time, self.W[0]),
'W_lfu': (self.time, self.W[1])
})
self.learning_rate.update(self.time)
if oblock in self:
miss = False
op = CacheOp.HIT
self.hit(oblock)
else:
evicted = self.miss(oblock)
self.visual.addWindow({'hit-rate': 0 if miss else 1}, self.time)
if not miss:
self.learning_rate.hitrate += 1
if miss:
self.pollution.incrementUniqueCount()
self.pollution.setUnique(oblock)
self.pollution.update(self.time)
return op, evicted
class LIRS:
class LIRS_Entry:
def __init__(self, oblock, is_LIR=False, in_cache=True):
self.oblock = oblock
self.is_LIR = is_LIR
self.in_cache = in_cache
def __repr__(self):
return "(o={}, is_LIR={}, in_cache={})".format(
self.oblock, self.is_LIR, self.in_cache)
def __init__(self, cache_size, **kwargs):
self.cache_size = cache_size
self.hirs_ratio = 0.01
process_kwargs(self, kwargs, acceptable_kws=['hirs_ratio'])
self.hirs_limit = max(2, int((self.cache_size * self.hirs_ratio)))
self.lirs_limit = self.cache_size - self.hirs_limit
self.hirs_count = 0
self.lirs_count = 0
self.nonresident = 0
# s stack, semi-split to find nonresident HIRs quickly
self.s = DequeDict()
self.nr_hirs = DequeDict()
# q, the resident HIR stack
self.q = DequeDict()
self.time = 0
self.last_oblock = None
self.pollution = Pollutionator(cache_size)
def __contains__(self, oblock):
if oblock in self.s:
return self.s[oblock].in_cache
return oblock in self.q
def _cacheFull(self):
return self.lirs_count + self.hirs_count == self.cache_size
def hitLIR(self, oblock):
lru_lir = self.s.first()
x = self.s[oblock]
self.s[oblock] = x
if lru_lir is x:
self.prune()
def prune(self):
while self.s:
x = self.s.first()
if x.is_LIR:
break
del self.s[x.oblock]
if not x.in_cache:
del self.nr_hirs[x.oblock]
self.nonresident -= 1
def hitHIRinLIRS(self, oblock):
x = self.s[oblock]
if x.in_cache:
del self.s[oblock]
del self.q[oblock]
self.hirs_count -= 1
else:
del self.s[oblock]
del self.nr_hirs[oblock]
self.nonresident -= 1
if self._cacheFull():
self.ejectHIR()
if self.lirs_count >= self.lirs_limit:
self.ejectLIR()
self.s[oblock] = x
x.in_cache = True
x.is_LIR = True
self.lirs_count += 1
def ejectLIR(self):
assert (self.s.first().is_LIR)
lru = self.s.popFirst()
self.lirs_count -= 1
lru.is_LIR = False
self.q[lru.oblock] = lru
self.hirs_count += 1
self.prune()
def ejectHIR(self):
lru = self.q.popFirst()
self.hirs_count -= 1
if lru.oblock in self.s:
self.nr_hirs[lru.oblock] = lru
lru.in_cache = False
self.nonresident += 1
self.pollution.remove(lru.oblock)
def hitHIRinQ(self, oblock):
x = self.q[oblock]
self.q[oblock] = x
self.s[oblock] = x
def limitStack(self):
while len(self.s) > (2 * self.cache_size):
lru = self.nr_hirs.popFirst()
del self.s[lru.oblock]
self.nonresident -= 1
def miss(self, oblock):
if self._cacheFull():
self.ejectHIR()
if self.lirs_count < self.lirs_limit and self.hirs_count == 0:
x = self.LIRS_Entry(oblock, is_LIR=True)
self.s[oblock] = x
self.lirs_count += 1
else:
x = self.LIRS_Entry(oblock, is_LIR=False)
self.s[oblock] = x
self.q[oblock] = x
self.hirs_count += 1
def request(self, oblock):
miss = oblock not in self
self.time += 1
if oblock != self.last_oblock:
self.last_oblock = oblock
if oblock in self.s:
x = self.s[oblock]
if x.is_LIR:
self.hitLIR(oblock)
else:
self.hitHIRinLIRS(oblock)
elif oblock in self.q:
self.hitHIRinQ(oblock)
else:
self.miss(oblock)
self.limitStack()
if miss:
self.pollution.incrementUniqueCount()
self.pollution.setUnique(oblock)
self.pollution.update(self.time)
return miss
class LFU:
class LFU_Entry:
def __init__(self, oblock, freq=1, time=0):
self.oblock = oblock
self.freq = freq
self.time = time
def __lt__(self, other):
if self.freq == other.freq:
return np.random.choice([True, False])
return self.freq < other.freq
def __repr__(self):
return "(o={}, f={}, t={})".format(self.oblock, self.freq,
self.time)
def __init__(self, cache_size, **kwargs):
self.cache_size = cache_size
self.lfu = HeapDict()
self.time = 0
np.random.seed(123)
self.pollution = Pollutionator(cache_size)
def __contains__(self, oblock):
return oblock in self.lfu
def addToCache(self, oblock):
x = self.LFU_Entry(oblock, freq=1, time=self.time)
self.lfu[oblock] = x
def hit(self, oblock):
x = self.lfu[oblock]
x.freq += 1
x.time = self.time
self.lfu[oblock] = x
def evict(self):
lfu_min = self.lfu.popMin()
self.pollution.remove(lfu_min.oblock)
return lfu_min
def miss(self, oblock):
if len(self.lfu) == self.cache_size:
self.evict()
self.addToCache(oblock)
def request(self, oblock):
miss = True
self.time += 1
if oblock in self:
miss = False
self.hit(oblock)
else:
self.miss(oblock)
# Pollutionator
if miss:
self.pollution.incrementUniqueCount()
self.pollution.setUnique(oblock)
self.pollution.update(self.time)
return miss