les: docs and minor fixes

les/api.go

@@ -33,7 +33,7 @@ var (
 	ErrTotalCap             = errors.New("total capacity exceeded")
 	ErrUnknownBenchmarkType = errors.New("unknown benchmark type")
 
-	dropCapacityDelay = time.Second
+	dropCapacityDelay = time.Second // delay applied to decreasing capacity changes
 )
 
 // PrivateLightServerAPI provides an API to access the LES light server.
@@ -129,6 +129,7 @@ func (api *PrivateLightServerAPI) GetClientCapacity(id enode.ID) hexutil.Uint64
 	return hexutil.Uint64(api.server.priorityClientPool.clients[id].cap)
 }
 
+// clientPool is implemented by both the free and priority client pools
 type clientPool interface {
 	peerSetNotify
 	setLimits(count int, totalCap uint64)
@@ -155,7 +156,7 @@ type scheduledUpdate struct {
 	totalCap, id uint64
 }
 
-// priorityClientInfo entries exist for all prioritized clients and currently connected free clients
+// priorityClientInfo entries exist for all prioritized clients and currently connected non-priority clients
 type priorityClientInfo struct {
 	cap       uint64 // zero for non-priority clients
 	connected bool
@@ -172,14 +173,12 @@ func newPriorityClientPool(freeClientCap uint64, ps *peerSet, child clientPool)
 	}
 }
 
-// connect should be called when a new client is connected. The callback function
-// is called when the assigned capacity is changed while the client is connected.
-// It returns the priority capacity or zero if the client is not prioritized.
-// It also returns whether the client can be accepted.
+// registerPeer is called when a new client is connected. If the client has no
+// priority assigned then it is passed to the child pool which may either keep it
+// or disconnect it.
 //
 // Note: priorityClientPool also stores a record about free clients while they are
-// connected in order to be able to assign priority to them later with the callback
-// function if necessary.
+// connected in order to be able to assign priority to them later.
 func (v *priorityClientPool) registerPeer(p *peer) {
 	v.lock.Lock()
 	defer v.lock.Unlock()
@@ -210,8 +209,8 @@ func (v *priorityClientPool) registerPeer(p *peer) {
 	}
 }
 
-// disconnect should be called when a client is disconnected.
-// It should be called for all clients accepted by connect even if not prioritized.
+// unregisterPeer is called when a client is disconnected. If the client has no
+// priority assigned then it is also removed from the child pool.
 func (v *priorityClientPool) unregisterPeer(p *peer) {
 	v.lock.Lock()
 	defer v.lock.Unlock()
@@ -311,7 +310,6 @@ func (v *priorityClientPool) setLimitsNow(count int, totalCap uint64) {
 			}
 		}
 	}
-
 	v.maxPeers = count
 	v.totalCap = totalCap
 	if v.child != nil {

les/benchmark.go

@@ -44,6 +44,7 @@ type requestBenchmark interface {
 	request(peer *peer, index int) error
 }
 
+// benchmarkBlockHeaders implements requestBenchmark
 type benchmarkBlockHeaders struct {
 	amount, skip    int
 	reverse, byHash bool
@@ -78,6 +79,7 @@ func (b *benchmarkBlockHeaders) request(peer *peer, index int) error {
 	}
 }
 
+// benchmarkBodiesOrReceipts implements requestBenchmark
 type benchmarkBodiesOrReceipts struct {
 	receipts bool
 	hashes   []common.Hash
@@ -100,6 +102,7 @@ func (b *benchmarkBodiesOrReceipts) request(peer *peer, index int) error {
 	}
 }
 
+// benchmarkProofsOrCode implements requestBenchmark
 type benchmarkProofsOrCode struct {
 	code     bool
 	headHash common.Hash
@@ -120,6 +123,7 @@ func (b *benchmarkProofsOrCode) request(peer *peer, index int) error {
 	}
 }
 
+// benchmarkHelperTrie implements requestBenchmark
 type benchmarkHelperTrie struct {
 	bloom                 bool
 	reqCount              int
@@ -162,6 +166,7 @@ func (b *benchmarkHelperTrie) request(peer *peer, index int) error {
 	return peer.RequestHelperTrieProofs(0, 0, reqs)
 }
 
+// benchmarkTxSend implements requestBenchmark
 type benchmarkTxSend struct {
 	txs types.Transactions
 }
@@ -189,6 +194,7 @@ func (b *benchmarkTxSend) request(peer *peer, index int) error {
 	return peer.SendTxs(0, 0, enc)
 }
 
+// benchmarkTxStatus implements requestBenchmark
 type benchmarkTxStatus struct{}
 
 func (b *benchmarkTxStatus) init(pm *ProtocolManager, count int) error {

les/server.go

@@ -142,6 +142,9 @@ func (s *LesServer) APIs() []rpc.API {
 	}
 }
 
+// startEventLoop starts an event handler loop that updates the recharge curve of
+// the client manager and adjusts the client pool's size according to the total
+// capacity updates coming from the client manager
 func (s *LesServer) startEventLoop() {
 	s.protocolManager.wg.Add(1)
 
@@ -154,7 +157,7 @@ func (s *LesServer) startEventLoop() {
 	totalCapacity := s.fcManager.SubscribeTotalCapacity(totalCapacityCh)
 
 	go func() {
-		for {
+		updateRecharge := func() {
 			if processing {
 				s.protocolManager.servingQueue.setThreads(s.thcBlockProcessing)
 				s.fcManager.SetRechargeCurve(flowcontrol.PieceWiseLinear{{0, 0}, {totalRecharge, totalRecharge}})
@@ -162,9 +165,13 @@ func (s *LesServer) startEventLoop() {
 				s.protocolManager.servingQueue.setThreads(s.thcNormal)
 				s.fcManager.SetRechargeCurve(flowcontrol.PieceWiseLinear{{0, 0}, {totalRecharge / 10, totalRecharge}, {totalRecharge, totalRecharge}})
 			}
+		}
+		for {
 			select {
 			case processing = <-blockProcFeed:
+				updateRecharge()
 			case totalRecharge = <-totalRechargeCh:
+				updateRecharge()
 			case totalCapacity = <-totalCapacityCh:
 				s.priorityClientPool.setLimits(s.maxPeers, totalCapacity)
 			case <-s.protocolManager.quitSync:

p2p/simulations/adapters/exec.go

@@ -181,7 +181,7 @@ func (n *ExecNode) Start(snapshots map[string][]byte) (err error) {
 	}
 
 	// start the one-shot server that waits for startup information
-	ctx, cancel := context.WithTimeout(context.Background(), 40*time.Second)
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
 	statusURL, statusC := n.waitForStartupJSON(ctx)