Merge pull request #2798 from ipfs/feat/smarter-bitswap

Make bitswap better

exchange/bitswap/decision/engine.go

@@ -3,6 +3,7 @@ package decision
 
 import (
 	"sync"
+	"time"
 
 	blocks "github.com/ipfs/go-ipfs/blocks"
 	bstore "github.com/ipfs/go-ipfs/blocks/blockstore"
@@ -68,7 +69,7 @@ type Engine struct {
 	// peerRequestQueue is a priority queue of requests received from peers.
 	// Requests are popped from the queue, packaged up, and placed in the
 	// outbox.
-	peerRequestQueue peerRequestQueue
+	peerRequestQueue *prq
 
 	// FIXME it's a bit odd for the client and the worker to both share memory
 	// (both modify the peerRequestQueue) and also to communicate over the
@@ -86,6 +87,8 @@ type Engine struct {
 	lock sync.Mutex // protects the fields immediatly below
 	// ledgerMap lists Ledgers by their Partner key.
 	ledgerMap map[peer.ID]*ledger
+
+	ticker *time.Ticker
 }
 
 func NewEngine(ctx context.Context, bs bstore.Blockstore) *Engine {
@@ -95,6 +98,7 @@ func NewEngine(ctx context.Context, bs bstore.Blockstore) *Engine {
 		peerRequestQueue: newPRQ(),
 		outbox:           make(chan (<-chan *Envelope), outboxChanBuffer),
 		workSignal:       make(chan struct{}, 1),
+		ticker:           time.NewTicker(time.Millisecond * 100),
 	}
 	go e.taskWorker(ctx)
 	return e
@@ -142,6 +146,9 @@ func (e *Engine) nextEnvelope(ctx context.Context) (*Envelope, error) {
 				return nil, ctx.Err()
 			case <-e.workSignal:
 				nextTask = e.peerRequestQueue.Pop()
+			case <-e.ticker.C:
+				e.peerRequestQueue.thawRound()
+				nextTask = e.peerRequestQueue.Pop()
 			}
 		}
 
@@ -191,9 +198,6 @@ func (e *Engine) Peers() []peer.ID {
 // MessageReceived performs book-keeping. Returns error if passed invalid
 // arguments.
 func (e *Engine) MessageReceived(p peer.ID, m bsmsg.BitSwapMessage) error {
-	e.lock.Lock()
-	defer e.lock.Unlock()
-
 	if len(m.Wantlist()) == 0 && len(m.Blocks()) == 0 {
 		log.Debugf("received empty message from %s", p)
 	}
@@ -206,6 +210,8 @@ func (e *Engine) MessageReceived(p peer.ID, m bsmsg.BitSwapMessage) error {
 	}()
 
 	l := e.findOrCreate(p)
+	l.lk.Lock()
+	defer l.lk.Unlock()
 	if m.Full() {
 		l.wantList = wl.New()
 	}
@@ -236,10 +242,12 @@ func (e *Engine) addBlock(block blocks.Block) {
 	work := false
 
 	for _, l := range e.ledgerMap {
+		l.lk.Lock()
 		if entry, ok := l.WantListContains(block.Key()); ok {
 			e.peerRequestQueue.Push(entry, l.Partner)
 			work = true
 		}
+		l.lk.Unlock()
 	}
 
 	if work {
@@ -261,9 +269,6 @@ func (e *Engine) AddBlock(block blocks.Block) {
 // send happen atomically
 
 func (e *Engine) MessageSent(p peer.ID, m bsmsg.BitSwapMessage) error {
-	e.lock.Lock()
-	defer e.lock.Unlock()
-
 	l := e.findOrCreate(p)
 	for _, block := range m.Blocks() {
 		l.SentBytes(len(block.Data()))
@@ -290,11 +295,13 @@ func (e *Engine) numBytesReceivedFrom(p peer.ID) uint64 {
 
 // ledger lazily instantiates a ledger
 func (e *Engine) findOrCreate(p peer.ID) *ledger {
+	e.lock.Lock()
 	l, ok := e.ledgerMap[p]
 	if !ok {
 		l = newLedger(p)
 		e.ledgerMap[p] = l
 	}
+	e.lock.Unlock()
 	return l
 }
 

exchange/bitswap/decision/ledger.go

@@ -1,6 +1,7 @@
 package decision
 
 import (
+	"sync"
 	"time"
 
 	key "github.com/ipfs/go-ipfs/blocks/key"
@@ -44,6 +45,8 @@ type ledger struct {
 	// sentToPeer is a set of keys to ensure we dont send duplicate blocks
 	// to a given peer
 	sentToPeer map[key.Key]time.Time
+
+	lk sync.Mutex
 }
 
 type debtRatio struct {

exchange/bitswap/decision/peer_request_queue.go

@@ -15,14 +15,16 @@ type peerRequestQueue interface {
 	Pop() *peerRequestTask
 	Push(entry wantlist.Entry, to peer.ID)
 	Remove(k key.Key, p peer.ID)
+
 	// NB: cannot expose simply expose taskQueue.Len because trashed elements
 	// may exist. These trashed elements should not contribute to the count.
 }
 
-func newPRQ() peerRequestQueue {
+func newPRQ() *prq {
 	return &prq{
 		taskMap:  make(map[string]*peerRequestTask),
 		partners: make(map[peer.ID]*activePartner),
+		frozen:   make(map[peer.ID]*activePartner),
 		pQueue:   pq.New(partnerCompare),
 	}
 }
@@ -38,6 +40,8 @@ type prq struct {
 	pQueue   pq.PQ
 	taskMap  map[string]*peerRequestTask
 	partners map[peer.ID]*activePartner
+
+	frozen map[peer.ID]*activePartner
 }
 
 // Push currently adds a new peerRequestTask to the end of the list
@@ -92,7 +96,7 @@ func (tl *prq) Pop() *peerRequestTask {
 	partner := tl.pQueue.Pop().(*activePartner)
 
 	var out *peerRequestTask
-	for partner.taskQueue.Len() > 0 {
+	for partner.taskQueue.Len() > 0 && partner.freezeVal == 0 {
 		out = partner.taskQueue.Pop().(*peerRequestTask)
 		delete(tl.taskMap, out.Key())
 		if out.trash {
@@ -120,11 +124,47 @@ func (tl *prq) Remove(k key.Key, p peer.ID) {
 		t.trash = true
 
 		// having canceled a block, we now account for that in the given partner
-		tl.partners[p].requests--
+		partner := tl.partners[p]
+		partner.requests--
+
+		// we now also 'freeze' that partner. If they sent us a cancel for a
+		// block we were about to send them, we should wait a short period of time
+		// to make sure we receive any other in-flight cancels before sending
+		// them a block they already potentially have
+		if partner.freezeVal == 0 {
+			tl.frozen[p] = partner
+		}
+
+		partner.freezeVal++
+		tl.pQueue.Update(partner.index)
 	}
 	tl.lock.Unlock()
 }
 
+func (tl *prq) fullThaw() {
+	tl.lock.Lock()
+	defer tl.lock.Unlock()
+
+	for id, partner := range tl.frozen {
+		partner.freezeVal = 0
+		delete(tl.frozen, id)
+		tl.pQueue.Update(partner.index)
+	}
+}
+
+func (tl *prq) thawRound() {
+	tl.lock.Lock()
+	defer tl.lock.Unlock()
+
+	for id, partner := range tl.frozen {
+		partner.freezeVal -= (partner.freezeVal + 1) / 2
+		if partner.freezeVal <= 0 {
+			delete(tl.frozen, id)
+		}
+		tl.pQueue.Update(partner.index)
+	}
+}
+
 type peerRequestTask struct {
 	Entry  wantlist.Entry
 	Target peer.ID
@@ -196,6 +236,8 @@ type activePartner struct {
 	// for the PQ interface
 	index int
 
+	freezeVal int
+
 	// priority queue of tasks belonging to this peer
 	taskQueue pq.PQ
 }
@@ -208,6 +250,7 @@ func newActivePartner() *activePartner {
 }
 
 // partnerCompare implements pq.ElemComparator
+// returns true if peer 'a' has higher priority than peer 'b'
 func partnerCompare(a, b pq.Elem) bool {
 	pa := a.(*activePartner)
 	pb := b.(*activePartner)
@@ -220,6 +263,14 @@ func partnerCompare(a, b pq.Elem) bool {
 	if pb.requests == 0 {
 		return true
 	}
+
+	if pa.freezeVal > pb.freezeVal {
+		return false
+	}
+	if pa.freezeVal < pb.freezeVal {
+		return true
+	}
+
 	if pa.active == pb.active {
 		// sorting by taskQueue.Len() aids in cleaning out trash entries faster
 		// if we sorted instead by requests, one peer could potentially build up

exchange/bitswap/decision/peer_request_queue_test.go

@@ -47,6 +47,8 @@ func TestPushPop(t *testing.T) {
 		prq.Remove(key.Key(consonant), partner)
 	}
 
+	prq.fullThaw()
+
 	var out []string
 	for {
 		received := prq.Pop()

exchange/bitswap/network/interface.go

@@ -25,9 +25,16 @@ type BitSwapNetwork interface {
 
 	ConnectTo(context.Context, peer.ID) error
 
+	NewMessageSender(context.Context, peer.ID) (MessageSender, error)
+
 	Routing
 }
 
+type MessageSender interface {
+	SendMsg(bsmsg.BitSwapMessage) error
+	Close() error
+}
+
 // Implement Receiver to receive messages from the BitSwapNetwork
 type Receiver interface {
 	ReceiveMessage(

exchange/bitswap/network/ipfs_impl.go

@@ -42,6 +42,27 @@ type impl struct {
 	receiver Receiver
 }
 
+type streamMessageSender struct {
+	s inet.Stream
+}
+
+func (s *streamMessageSender) Close() error {
+	return s.s.Close()
+}
+
+func (s *streamMessageSender) SendMsg(msg bsmsg.BitSwapMessage) error {
+	return msg.ToNet(s.s)
+}
+
+func (bsnet *impl) NewMessageSender(ctx context.Context, p peer.ID) (MessageSender, error) {
+	s, err := bsnet.newStreamToPeer(ctx, p)
+	if err != nil {
+		return nil, err
+	}
+
+	return &streamMessageSender{s: s}, nil
+}
+
 func (bsnet *impl) newStreamToPeer(ctx context.Context, p peer.ID) (inet.Stream, error) {
 
 	// first, make sure we're connected.

exchange/bitswap/testnet/virtual.go

@@ -112,6 +112,30 @@ func (nc *networkClient) FindProvidersAsync(ctx context.Context, k key.Key, max
 	return out
 }
 
+type messagePasser struct {
+	net    *network
+	target peer.ID
+	local  peer.ID
+	ctx    context.Context
+}
+
+func (mp *messagePasser) SendMsg(m bsmsg.BitSwapMessage) error {
+	return mp.net.SendMessage(mp.ctx, mp.local, mp.target, m)
+}
+
+func (mp *messagePasser) Close() error {
+	return nil
+}
+
+func (n *networkClient) NewMessageSender(ctx context.Context, p peer.ID) (bsnet.MessageSender, error) {
+	return &messagePasser{
+		net:    n.network,
+		target: p,
+		local:  n.local,
+		ctx:    ctx,
+	}, nil
+}
+
 // Provide provides the key to the network
 func (nc *networkClient) Provide(ctx context.Context, k key.Key) error {
 	return nc.routing.Provide(ctx, k)