Merge pull request #1953 from karalabe/switch-to-fast-peers

eth/downloader: fetch data proportionally to peer capacity

Author: obscuren

eth/downloader/downloader.go

@@ -45,16 +45,17 @@ var (
 	MaxReceiptFetch = 256 // Amount of transaction receipts to allow fetching per request
 	MaxStateFetch   = 384 // Amount of node state values to allow fetching per request
 
-	hashTTL        = 5 * time.Second    // [eth/61] Time it takes for a hash request to time out
-	blockSoftTTL   = 3 * time.Second    // [eth/61] Request completion threshold for increasing or decreasing a peer's bandwidth
-	blockHardTTL   = 3 * blockSoftTTL   // [eth/61] Maximum time allowance before a block request is considered expired
-	headerTTL      = 5 * time.Second    // [eth/62] Time it takes for a header request to time out
-	bodySoftTTL    = 3 * time.Second    // [eth/62] Request completion threshold for increasing or decreasing a peer's bandwidth
-	bodyHardTTL    = 3 * bodySoftTTL    // [eth/62] Maximum time allowance before a block body request is considered expired
-	receiptSoftTTL = 3 * time.Second    // [eth/63] Request completion threshold for increasing or decreasing a peer's bandwidth
-	receiptHardTTL = 3 * receiptSoftTTL // [eth/63] Maximum time allowance before a receipt request is considered expired
-	stateSoftTTL   = 2 * time.Second    // [eth/63] Request completion threshold for increasing or decreasing a peer's bandwidth
-	stateHardTTL   = 3 * stateSoftTTL   // [eth/63] Maximum time allowance before a node data request is considered expired
+	hashTTL        = 3 * time.Second     // [eth/61] Time it takes for a hash request to time out
+	blockTargetRTT = 3 * time.Second / 2 // [eth/61] Target time for completing a block retrieval request
+	blockTTL       = 3 * blockTargetRTT  // [eth/61] Maximum time allowance before a block request is considered expired
+
+	headerTTL        = 3 * time.Second      // [eth/62] Time it takes for a header request to time out
+	bodyTargetRTT    = 3 * time.Second / 2  // [eth/62] Target time for completing a block body retrieval request
+	bodyTTL          = 3 * bodyTargetRTT    // [eth/62] Maximum time allowance before a block body request is considered expired
+	receiptTargetRTT = 3 * time.Second / 2  // [eth/63] Target time for completing a receipt retrieval request
+	receiptTTL       = 3 * receiptTargetRTT // [eth/63] Maximum time allowance before a receipt request is considered expired
+	stateTargetRTT   = 2 * time.Second / 2  // [eth/63] Target time for completing a state trie retrieval request
+	stateTTL         = 3 * stateTargetRTT   // [eth/63] Maximum time allowance before a node data request is considered expired
 
 	maxQueuedHashes   = 256 * 1024 // [eth/61] Maximum number of hashes to queue for import (DOS protection)
 	maxQueuedHeaders  = 256 * 1024 // [eth/62] Maximum number of headers to queue for import (DOS protection)
@@ -486,7 +487,7 @@ func (d *Downloader) fetchHeight61(p *peer) (uint64, error) {
 	// Request the advertised remote head block and wait for the response
 	go p.getBlocks([]common.Hash{p.head})
 
-	timeout := time.After(blockSoftTTL)
+	timeout := time.After(hashTTL)
 	for {
 		select {
 		case <-d.cancelCh:
@@ -779,47 +780,27 @@ func (d *Downloader) fetchBlocks61(from uint64) error {
 			// If the peer was previously banned and failed to deliver it's pack
 			// in a reasonable time frame, ignore it's message.
 			if peer := d.peers.Peer(packet.PeerId()); peer != nil {
-				// Deliver the received chunk of blocks, and demote in case of errors
 				blocks := packet.(*blockPack).blocks
-				err := d.queue.DeliverBlocks(peer.id, blocks)
-				switch err {
-				case nil:
-					// If no blocks were delivered, demote the peer (need the delivery above)
-					if len(blocks) == 0 {
-						peer.Demote()
-						peer.SetBlocksIdle()
-						glog.V(logger.Detail).Infof("%s: no blocks delivered", peer)
-						break
-					}
-					// All was successful, promote the peer and potentially start processing
-					peer.Promote()
-					peer.SetBlocksIdle()
-					glog.V(logger.Detail).Infof("%s: delivered %d blocks", peer, len(blocks))
 
-				case errInvalidChain:
-					// The hash chain is invalid (blocks are not ordered properly), abort
+				// Deliver the received chunk of blocks and check chain validity
+				accepted, err := d.queue.DeliverBlocks(peer.id, blocks)
+				if err == errInvalidChain {
 					return err
-
-				case errNoFetchesPending:
-					// Peer probably timed out with its delivery but came through
-					// in the end, demote, but allow to to pull from this peer.
-					peer.Demote()
-					peer.SetBlocksIdle()
-					glog.V(logger.Detail).Infof("%s: out of bound delivery", peer)
-
-				case errStaleDelivery:
-					// Delivered something completely else than requested, usually
-					// caused by a timeout and delivery during a new sync cycle.
-					// Don't set it to idle as the original request should still be
-					// in flight.
-					peer.Demote()
-					glog.V(logger.Detail).Infof("%s: stale delivery", peer)
-
+				}
+				// Unless a peer delivered something completely else than requested (usually
+				// caused by a timed out request which came through in the end), set it to
+				// idle. If the delivery's stale, the peer should have already been idled.
+				if err != errStaleDelivery {
+					peer.SetBlocksIdle(accepted)
+				}
+				// Issue a log to the user to see what's going on
+				switch {
+				case err == nil && len(blocks) == 0:
+					glog.V(logger.Detail).Infof("%s: no blocks delivered", peer)
+				case err == nil:
+					glog.V(logger.Detail).Infof("%s: delivered %d blocks", peer, len(blocks))
 				default:
-					// Peer did something semi-useful, demote but keep it around
-					peer.Demote()
-					peer.SetBlocksIdle()
-					glog.V(logger.Detail).Infof("%s: delivery partially failed: %v", peer, err)
+					glog.V(logger.Detail).Infof("%s: delivery failed: %v", peer, err)
 				}
 			}
 			// Blocks arrived, try to update the progress
@@ -852,10 +833,15 @@ func (d *Downloader) fetchBlocks61(from uint64) error {
 				return errNoPeers
 			}
 			// Check for block request timeouts and demote the responsible peers
-			for _, pid := range d.queue.ExpireBlocks(blockHardTTL) {
+			for pid, fails := range d.queue.ExpireBlocks(blockTTL) {
 				if peer := d.peers.Peer(pid); peer != nil {
-					peer.Demote()
-					glog.V(logger.Detail).Infof("%s: block delivery timeout", peer)
+					if fails > 1 {
+						glog.V(logger.Detail).Infof("%s: block delivery timeout", peer)
+						peer.SetBlocksIdle(0)
+					} else {
+						glog.V(logger.Debug).Infof("%s: stalling block delivery, dropping", peer)
+						d.dropPeer(pid)
+					}
 				}
 			}
 			// If there's nothing more to fetch, wait or terminate
@@ -1281,14 +1267,14 @@ func (d *Downloader) fetchBodies(from uint64) error {
 	glog.V(logger.Debug).Infof("Downloading block bodies from #%d", from)
 
 	var (
-		deliver = func(packet dataPack) error {
+		deliver = func(packet dataPack) (int, error) {
 			pack := packet.(*bodyPack)
 			return d.queue.DeliverBodies(pack.peerId, pack.transactions, pack.uncles)
 		}
-		expire   = func() []string { return d.queue.ExpireBodies(bodyHardTTL) }
+		expire   = func() map[string]int { return d.queue.ExpireBodies(bodyTTL) }
 		fetch    = func(p *peer, req *fetchRequest) error { return p.FetchBodies(req) }
 		capacity = func(p *peer) int { return p.BlockCapacity() }
-		setIdle  = func(p *peer) { p.SetBodiesIdle() }
+		setIdle  = func(p *peer, accepted int) { p.SetBodiesIdle(accepted) }
 	)
 	err := d.fetchParts(errCancelBodyFetch, d.bodyCh, deliver, d.bodyWakeCh, expire,
 		d.queue.PendingBlocks, d.queue.InFlightBlocks, d.queue.ShouldThrottleBlocks, d.queue.ReserveBodies,
@@ -1305,14 +1291,14 @@ func (d *Downloader) fetchReceipts(from uint64) error {
 	glog.V(logger.Debug).Infof("Downloading receipts from #%d", from)
 
 	var (
-		deliver = func(packet dataPack) error {
+		deliver = func(packet dataPack) (int, error) {
 			pack := packet.(*receiptPack)
 			return d.queue.DeliverReceipts(pack.peerId, pack.receipts)
 		}
-		expire   = func() []string { return d.queue.ExpireReceipts(receiptHardTTL) }
+		expire   = func() map[string]int { return d.queue.ExpireReceipts(receiptTTL) }
 		fetch    = func(p *peer, req *fetchRequest) error { return p.FetchReceipts(req) }
 		capacity = func(p *peer) int { return p.ReceiptCapacity() }
-		setIdle  = func(p *peer) { p.SetReceiptsIdle() }
+		setIdle  = func(p *peer, accepted int) { p.SetReceiptsIdle(accepted) }
 	)
 	err := d.fetchParts(errCancelReceiptFetch, d.receiptCh, deliver, d.receiptWakeCh, expire,
 		d.queue.PendingReceipts, d.queue.InFlightReceipts, d.queue.ShouldThrottleReceipts, d.queue.ReserveReceipts,
@@ -1329,7 +1315,7 @@ func (d *Downloader) fetchNodeData() error {
 	glog.V(logger.Debug).Infof("Downloading node state data")
 
 	var (
-		deliver = func(packet dataPack) error {
+		deliver = func(packet dataPack) (int, error) {
 			start := time.Now()
 			return d.queue.DeliverNodeData(packet.PeerId(), packet.(*statePack).states, func(err error, delivered int) {
 				if err != nil {
@@ -1352,14 +1338,14 @@ func (d *Downloader) fetchNodeData() error {
 				glog.V(logger.Info).Infof("imported %d state entries in %v: processed %d in total", delivered, time.Since(start), d.syncStatsStateDone)
 			})
 		}
-		expire   = func() []string { return d.queue.ExpireNodeData(stateHardTTL) }
+		expire   = func() map[string]int { return d.queue.ExpireNodeData(stateTTL) }
 		throttle = func() bool { return false }
 		reserve  = func(p *peer, count int) (*fetchRequest, bool, error) {
 			return d.queue.ReserveNodeData(p, count), false, nil
 		}
 		fetch    = func(p *peer, req *fetchRequest) error { return p.FetchNodeData(req) }
 		capacity = func(p *peer) int { return p.NodeDataCapacity() }
-		setIdle  = func(p *peer) { p.SetNodeDataIdle() }
+		setIdle  = func(p *peer, accepted int) { p.SetNodeDataIdle(accepted) }
 	)
 	err := d.fetchParts(errCancelStateFetch, d.stateCh, deliver, d.stateWakeCh, expire,
 		d.queue.PendingNodeData, d.queue.InFlightNodeData, throttle, reserve, nil, fetch,
@@ -1372,10 +1358,10 @@ func (d *Downloader) fetchNodeData() error {
 // fetchParts iteratively downloads scheduled block parts, taking any available
 // peers, reserving a chunk of fetch requests for each, waiting for delivery and
 // also periodically checking for timeouts.
-func (d *Downloader) fetchParts(errCancel error, deliveryCh chan dataPack, deliver func(packet dataPack) error, wakeCh chan bool,
-	expire func() []string, pending func() int, inFlight func() bool, throttle func() bool, reserve func(*peer, int) (*fetchRequest, bool, error),
+func (d *Downloader) fetchParts(errCancel error, deliveryCh chan dataPack, deliver func(dataPack) (int, error), wakeCh chan bool,
+	expire func() map[string]int, pending func() int, inFlight func() bool, throttle func() bool, reserve func(*peer, int) (*fetchRequest, bool, error),
 	fetchHook func([]*types.Header), fetch func(*peer, *fetchRequest) error, cancel func(*fetchRequest), capacity func(*peer) int,
-	idle func() ([]*peer, int), setIdle func(*peer), kind string) error {
+	idle func() ([]*peer, int), setIdle func(*peer, int), kind string) error {
 
 	// Create a ticker to detect expired retrieval tasks
 	ticker := time.NewTicker(100 * time.Millisecond)
@@ -1394,45 +1380,25 @@ func (d *Downloader) fetchParts(errCancel error, deliveryCh chan dataPack, deliv
 			// If the peer was previously banned and failed to deliver it's pack
 			// in a reasonable time frame, ignore it's message.
 			if peer := d.peers.Peer(packet.PeerId()); peer != nil {
-				// Deliver the received chunk of data, and demote in case of errors
-				switch err := deliver(packet); err {
-				case nil:
-					// If no blocks were delivered, demote the peer (need the delivery above to clean internal queue!)
-					if packet.Items() == 0 {
-						peer.Demote()
-						setIdle(peer)
-						glog.V(logger.Detail).Infof("%s: no %s delivered", peer, strings.ToLower(kind))
-						break
-					}
-					// All was successful, promote the peer and potentially start processing
-					peer.Promote()
-					setIdle(peer)
-					glog.V(logger.Detail).Infof("%s: delivered %s %s(s)", peer, packet.Stats(), strings.ToLower(kind))
-
-				case errInvalidChain:
-					// The hash chain is invalid (blocks are not ordered properly), abort
+				// Deliver the received chunk of data and check chain validity
+				accepted, err := deliver(packet)
+				if err == errInvalidChain {
 					return err
-
-				case errNoFetchesPending:
-					// Peer probably timed out with its delivery but came through
-					// in the end, demote, but allow to to pull from this peer.
-					peer.Demote()
-					setIdle(peer)
-					glog.V(logger.Detail).Infof("%s: out of bound %s delivery", peer, strings.ToLower(kind))
-
-				case errStaleDelivery:
-					// Delivered something completely else than requested, usually
-					// caused by a timeout and delivery during a new sync cycle.
-					// Don't set it to idle as the original request should still be
-					// in flight.
-					peer.Demote()
-					glog.V(logger.Detail).Infof("%s: %s stale delivery", peer, strings.ToLower(kind))
-
+				}
+				// Unless a peer delivered something completely else than requested (usually
+				// caused by a timed out request which came through in the end), set it to
+				// idle. If the delivery's stale, the peer should have already been idled.
+				if err != errStaleDelivery {
+					setIdle(peer, accepted)
+				}
+				// Issue a log to the user to see what's going on
+				switch {
+				case err == nil && packet.Items() == 0:
+					glog.V(logger.Detail).Infof("%s: no %s delivered", peer, strings.ToLower(kind))
+				case err == nil:
+					glog.V(logger.Detail).Infof("%s: delivered %s %s(s)", peer, packet.Stats(), strings.ToLower(kind))
 				default:
-					// Peer did something semi-useful, demote but keep it around
-					peer.Demote()
-					setIdle(peer)
-					glog.V(logger.Detail).Infof("%s: %s delivery partially failed: %v", peer, strings.ToLower(kind), err)
+					glog.V(logger.Detail).Infof("%s: %s delivery failed: %v", peer, strings.ToLower(kind), err)
 				}
 			}
 			// Blocks assembled, try to update the progress
@@ -1465,11 +1431,15 @@ func (d *Downloader) fetchParts(errCancel error, deliveryCh chan dataPack, deliv
 				return errNoPeers
 			}
 			// Check for fetch request timeouts and demote the responsible peers
-			for _, pid := range expire() {
+			for pid, fails := range expire() {
 				if peer := d.peers.Peer(pid); peer != nil {
-					peer.Demote()
-					setIdle(peer)
-					glog.V(logger.Detail).Infof("%s: %s delivery timeout", peer, strings.ToLower(kind))
+					if fails > 1 {
+						glog.V(logger.Detail).Infof("%s: %s delivery timeout", peer, strings.ToLower(kind))
+						setIdle(peer, 0)
+					} else {
+						glog.V(logger.Debug).Infof("%s: stalling %s delivery, dropping", peer, strings.ToLower(kind))
+						d.dropPeer(pid)
+					}
 				}
 			}
 			// If there's nothing more to fetch, wait or terminate