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les: address comments
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@rjl493456442
rjl493456442 committed Oct 31, 2019
1 parent 6f25de9 commit 2351fdf
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Showing 2 changed files with 54 additions and 58 deletions.
94 changes: 45 additions & 49 deletions les/clientpool.go
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Original file line number Diff line number Diff line change
Expand Up @@ -34,24 +34,21 @@ import (
)

const (
negBalanceExpTC = time.Minute // time constant for exponentially reducing negative balance
fixedPointMultiplier = 0x1000000 // constant to convert logarithms to fixed point format
lazyQueueRefresh = time.Second * 10 // refresh period of the connected queue
persistCumTimeRefresh = time.Minute * 5 // refresh period of the cumulative running time persistence
posBalanceCacheLimit = 8192 // the maximum number of cached items in positive balance queue
negBalanceCacheLimit = 8192 // the maximum number of cached items in negative balance queue

// freeConnectedBias is applied to already connected clients when new client
// is "free client". So that already connected client won't be kicked out very
// soon.
freeConnectedBias = time.Minute * 3

// priorityConnectedBias is applied to already connected clients when new client
// is "priority client". The value is smaller than freeConnectedBias, so that
// we can ensure most of new priority client can be accepted when pool is full.
// But if the balance of priority client is very small, there is no reason for
// very high priority.
priorityConnectedBias = time.Second * 30
negBalanceExpTC = time.Hour // time constant for exponentially reducing negative balance
fixedPointMultiplier = 0x1000000 // constant to convert logarithms to fixed point format
lazyQueueRefresh = time.Second * 10 // refresh period of the connected queue
persistCumulativeTimeRefresh = time.Minute * 5 // refresh period of the cumulative running time persistence
posBalanceCacheLimit = 8192 // the maximum number of cached items in positive balance queue
negBalanceCacheLimit = 8192 // the maximum number of cached items in negative balance queue

// connectedBias is applied to already connected clients So that
// already connected client won't be kicked out very soon and we
// can ensure all connected clients can have enough time to request
// or sync some data.
//
// todo(rjl493456442) make it configurable. It can be the option of
// free trial time!
connectedBias = time.Minute * 3
)

// clientPool implements a client database that assigns a priority to each client
Expand All @@ -69,12 +66,12 @@ const (
// accepting and instantly kicking out clients. In theory, we try to ensure that
// each client can have several minutes of connection time.
//
// Balances of disconnected clients are stored in posBalanceQueue and negBalanceQueue
// and are also saved in the database. Negative balance is transformed into a
// logarithmic form with a constantly shifting linear offset in order to implement
// an exponential decrease. negBalanceQueue has a limited size and drops the smallest
// values when necessary. Positive balances are stored in the database as long as
// they exist, posBalanceQueue only acts as a cache for recently accessed entries.
// Balances of disconnected clients are stored in nodeDB including postive balance
// and negative banalce. Negative balance is transformed into a logarithmic form
// with a constantly shifting linear offset in order to implement an exponential
// decrease. Besides nodeDB will have a background thread to check the negative
// balance of disconnected client. If the balance is low enough, then the record
// will be dropped.
type clientPool struct {
ndb *nodeDB
lock sync.Mutex
Expand All @@ -88,13 +85,13 @@ type clientPool struct {

posFactors, negFactors priceFactors

connLimit int // The maximum number of connections that clientpool can support
capLimit uint64 // The maximum cumulative capacity that clientpool can support
connectedCap uint64 // The sum of the capacity of the current clientpool connected
freeClientCap uint64 // The capacity value of each free client
startTime mclock.AbsTime // The timestamp at which the clientpool started running
startCumTime int64 // The cumulative running time of clientpool at the start point.
disableBias bool // Disable connection bias(used in testing)
connLimit int // The maximum number of connections that clientpool can support
capLimit uint64 // The maximum cumulative capacity that clientpool can support
connectedCap uint64 // The sum of the capacity of the current clientpool connected
freeClientCap uint64 // The capacity value of each free client
startTime mclock.AbsTime // The timestamp at which the clientpool started running
cumulativeTime int64 // The cumulative running time of clientpool at the start point.
disableBias bool // Disable connection bias(used in testing)
}

// clientPeer represents a client in the pool.
Expand Down Expand Up @@ -165,7 +162,7 @@ func newClientPool(db ethdb.Database, freeClientCap uint64, clock mclock.Clock,
freeClientCap: freeClientCap,
removePeer: removePeer,
startTime: clock.Now(),
startCumTime: ndb.getCumTime(),
cumulativeTime: ndb.getCumulativeTime(),
stopCh: make(chan struct{}),
}
// If the negative balance of free client is even lower than 1,
Expand All @@ -184,8 +181,8 @@ func newClientPool(db ethdb.Database, freeClientCap uint64, clock mclock.Clock,
pool.lock.Lock()
pool.connectedQueue.Refresh()
pool.lock.Unlock()
case <-clock.After(persistCumTimeRefresh):
pool.ndb.setCumTime(pool.logOffset(clock.Now()))
case <-clock.After(persistCumulativeTimeRefresh):
pool.ndb.setCumulativeTime(pool.logOffset(clock.Now()))
case <-pool.stopCh:
return
}
Expand All @@ -200,7 +197,7 @@ func (f *clientPool) stop() {
f.lock.Lock()
f.closed = true
f.lock.Unlock()
f.ndb.setCumTime(f.logOffset(f.clock.Now()))
f.ndb.setCumulativeTime(f.logOffset(f.clock.Now()))
f.ndb.close()
}

Expand All @@ -225,14 +222,15 @@ func (f *clientPool) connect(peer clientPeer, capacity uint64) bool {
var (
posBalance uint64
negBalance uint64
now = f.clock.Now()
)
pb := f.ndb.getOrNewPB(id)
posBalance = pb.value
e := &clientInfo{pool: f, peer: peer, address: freeID, queueIndex: -1, id: id, priority: posBalance != 0}

nb := f.ndb.getOrNewNB(freeID)
if nb.logValue != 0 {
negBalance = uint64(math.Exp(float64(nb.logValue-f.logOffset(f.clock.Now())) / fixedPointMultiplier))
negBalance = uint64(math.Exp(float64(nb.logValue-f.logOffset(now)) / fixedPointMultiplier))
negBalance *= uint64(time.Second)
}
// If the client is a free client, assign with a low free capacity,
Expand Down Expand Up @@ -271,14 +269,11 @@ func (f *clientPool) connect(peer clientPeer, capacity uint64) bool {
newCount--
return newCapacity > f.capLimit || newCount > f.connLimit
})
bias := freeConnectedBias
if e.priority {
bias = priorityConnectedBias
}
bias := connectedBias
if f.disableBias {
bias = 0
}
if newCapacity > f.capLimit || newCount > f.connLimit || (e.balanceTracker.estimatedPriority(f.clock.Now()+mclock.AbsTime(bias), false)-kickPriority) > 0 {
if newCapacity > f.capLimit || newCount > f.connLimit || (e.balanceTracker.estimatedPriority(now+mclock.AbsTime(bias), false)-kickPriority) > 0 {
for _, c := range kickList {
f.connectedQueue.Push(c)
}
Expand All @@ -288,17 +283,18 @@ func (f *clientPool) connect(peer clientPeer, capacity uint64) bool {
}
// accept new client, drop old ones
for _, c := range kickList {
f.dropClient(c, f.clock.Now(), true)
f.dropClient(c, now, true)
}
}
// Register new client to connection queue.
f.connectedMap[id] = e
f.connectedQueue.Push(e)
f.connectedCap += e.capacity

// If the current client is a paid client, notify it to update the capacity.
// And also monitor the status of client, downgrade it to normal client if
// positive balance is used up.
if e.capacity != f.freeClientCap {
if e.priority {
e.peer.updateCapacity(e.capacity)
e.balanceTracker.addCallback(balanceCallbackZero, 0, func() { f.balanceExhausted(id) })
}
Expand Down Expand Up @@ -359,7 +355,7 @@ func (f *clientPool) finalizeBalance(c *clientInfo, now mclock.AbsTime) {
pb.value = pos
f.ndb.setPB(c.id, pb)

neg /= uint64(time.Second)
neg /= uint64(time.Second) // Convert the expanse to second level.
if neg > 1 {
nb.logValue = int64(math.Log(float64(neg))*fixedPointMultiplier) + f.logOffset(now)
f.ndb.setNB(c.address, nb)
Expand Down Expand Up @@ -420,12 +416,12 @@ func (f *clientPool) requestCost(p *peer, cost uint64) {
// representation of negative balance
//
// From another point of view, the result returned by the function represents
// the total time that the clientpool is cumulatively running(total_minutes/multiplier).
// the total time that the clientpool is cumulatively running(total_hours/multiplier).
func (f *clientPool) logOffset(now mclock.AbsTime) int64 {
// Note: fixedPointMultiplier acts as a multiplier here; the reason for dividing the divisor
// is to avoid int64 overflow. We assume that int64(negBalanceExpTC) >> fixedPointMultiplier.
cumTime := int64((time.Duration(now - f.startTime)) / (negBalanceExpTC / fixedPointMultiplier))
return f.startCumTime + cumTime
cumulativeTime := int64((time.Duration(now - f.startTime)) / (negBalanceExpTC / fixedPointMultiplier))
return f.cumulativeTime + cumulativeTime
}

// setPriceFactors changes pricing factors for both positive and negative balances.
Expand Down Expand Up @@ -585,15 +581,15 @@ func (db *nodeDB) key(id []byte, neg bool) []byte {
return db.auxbuf[:len(prefix)+len(db.verbuf)+len(id)]
}

func (db *nodeDB) getCumTime() int64 {
func (db *nodeDB) getCumulativeTime() int64 {
blob, err := db.db.Get(append(cumulativeRunningTimeKey, db.verbuf[:]...))
if err != nil || len(blob) == 0 {
return 0
}
return int64(binary.BigEndian.Uint64(blob))
}

func (db *nodeDB) setCumTime(v int64) {
func (db *nodeDB) setCumulativeTime(v int64) {
binary.BigEndian.PutUint64(db.auxbuf[:8], uint64(v))
db.db.Put(append(cumulativeRunningTimeKey, db.verbuf[:]...), db.auxbuf[:8])
}
Expand Down
18 changes: 9 additions & 9 deletions les/clientpool_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -214,7 +214,7 @@ func TestConnectPaidClientToFullPool(t *testing.T) {
t.Fatalf("Low balance paid client should be rejected")
}
clock.Run(time.Second)
pool.addBalance(poolTestPeer(12).ID(), 1000000000*60, false) // Add high balance to new paid client
pool.addBalance(poolTestPeer(12).ID(), 1000000000*60*3, false) // Add high balance to new paid client
if !pool.connect(poolTestPeer(12), 1) {
t.Fatalf("High balance paid client should be accpected")
}
Expand All @@ -238,7 +238,7 @@ func TestPaidClientKickedOut(t *testing.T) {
clock.Run(time.Millisecond)
}
clock.Run(time.Second)
clock.Run(freeConnectedBias)
clock.Run(connectedBias)
if !pool.connect(poolTestPeer(11), 0) {
t.Fatalf("Free client should be accectped")
}
Expand Down Expand Up @@ -465,9 +465,9 @@ func TestNodeDB(t *testing.T) {
}
}
}
ndb.setCumTime(100)
if ndb.getCumTime() != 100 {
t.Fatalf("Cumulative time mismatch, want %v, got %v", 100, ndb.getCumTime())
ndb.setCumulativeTime(100)
if ndb.getCumulativeTime() != 100 {
t.Fatalf("Cumulative time mismatch, want %v, got %v", 100, ndb.getCumulativeTime())
}
}

Expand All @@ -490,10 +490,10 @@ func TestNodeDBExpiration(t *testing.T) {
ip string
balance negBalance
}{
{"127.0.0.1", negBalance{logValue: 10}},
{"127.0.0.2", negBalance{logValue: 10}},
{"127.0.0.3", negBalance{logValue: 10}},
{"127.0.0.4", negBalance{logValue: 10}},
{"127.0.0.1", negBalance{logValue: 1}},
{"127.0.0.2", negBalance{logValue: 1}},
{"127.0.0.3", negBalance{logValue: 1}},
{"127.0.0.4", negBalance{logValue: 1}},
}
for _, c := range cases {
ndb.setNB(c.ip, c.balance)
Expand Down

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