core: txpool stable underprice drop order, perf fixes

3 files changed, 101 insertions, 24 deletions

diff --git a/core/tx_list.go b/core/tx_list.go
index 55fc42617..ea6ee7019 100644
--- a/core/tx_list.go
+++ b/core/tx_list.go
@@ -367,9 +367,20 @@ func (l *txList) Flatten() types.Transactions {
 // price-sorted transactions to discard when the pool fills up.
 type priceHeap []*types.Transaction
 
-func (h priceHeap) Len() int           { return len(h) }
-func (h priceHeap) Less(i, j int) bool { return h[i].GasPrice().Cmp(h[j].GasPrice()) < 0 }
-func (h priceHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }
+func (h priceHeap) Len() int      { return len(h) }
+func (h priceHeap) Swap(i, j int) { h[i], h[j] = h[j], h[i] }
+
+func (h priceHeap) Less(i, j int) bool {
+	// Sort primarily by price, returning the cheaper one
+	switch h[i].GasPrice().Cmp(h[j].GasPrice()) {
+	case -1:
+		return true
+	case 1:
+		return false
+	}
+	// If the prices match, stabilize via nonces (high nonce is worse)
+	return h[i].Nonce() > h[j].Nonce()
+}
 
 func (h *priceHeap) Push(x interface{}) {
 	*h = append(*h, x.(*types.Transaction))
diff --git a/core/tx_pool.go b/core/tx_pool.go
index 089bd215a..a554f6611 100644
--- a/core/tx_pool.go
+++ b/core/tx_pool.go
@@ -320,7 +320,7 @@ func (pool *TxPool) loop() {
 				// Any non-locals old enough should be removed
 				if time.Since(pool.beats[addr]) > pool.config.Lifetime {
 					for _, tx := range pool.queue[addr].Flatten() {
-						pool.removeTx(tx.Hash())
+						pool.removeTx(tx.Hash(), true)
 					}
 				}
 			}
@@ -468,7 +468,7 @@ func (pool *TxPool) SetGasPrice(price *big.Int) {
 
 	pool.gasPrice = price
 	for _, tx := range pool.priced.Cap(price, pool.locals) {
-		pool.removeTx(tx.Hash())
+		pool.removeTx(tx.Hash(), false)
 	}
 	log.Info("Transaction pool price threshold updated", "price", price)
 }
@@ -630,7 +630,7 @@ func (pool *TxPool) add(tx *types.Transaction, local bool) (bool, error) {
 		for _, tx := range drop {
 			log.Trace("Discarding freshly underpriced transaction", "hash", tx.Hash(), "price", tx.GasPrice())
 			underpricedTxCounter.Inc(1)
-			pool.removeTx(tx.Hash())
+			pool.removeTx(tx.Hash(), false)
 		}
 	}
 	// If the transaction is replacing an already pending one, do directly
@@ -695,8 +695,10 @@ func (pool *TxPool) enqueueTx(hash common.Hash, tx *types.Transaction) (bool, er
 		pool.priced.Removed()
 		queuedReplaceCounter.Inc(1)
 	}
-	pool.all[hash] = tx
-	pool.priced.Put(tx)
+	if pool.all[hash] == nil {
+		pool.all[hash] = tx
+		pool.priced.Put(tx)
+	}
 	return old != nil, nil
 }
 
@@ -862,7 +864,7 @@ func (pool *TxPool) Get(hash common.Hash) *types.Transaction {
 
 // removeTx removes a single transaction from the queue, moving all subsequent
 // transactions back to the future queue.
-func (pool *TxPool) removeTx(hash common.Hash) {
+func (pool *TxPool) removeTx(hash common.Hash, outofbound bool) {
 	// Fetch the transaction we wish to delete
 	tx, ok := pool.all[hash]
 	if !ok {
@@ -872,8 +874,9 @@ func (pool *TxPool) removeTx(hash common.Hash) {
 
 	// Remove it from the list of known transactions
 	delete(pool.all, hash)
-	pool.priced.Removed()
-
+	if outofbound {
+		pool.priced.Removed()
+	}
 	// Remove the transaction from the pending lists and reset the account nonce
 	if pending := pool.pending[addr]; pending != nil {
 		if removed, invalids := pending.Remove(tx); removed {
@@ -1052,7 +1055,7 @@ func (pool *TxPool) promoteExecutables(accounts []common.Address) {
 			// Drop all transactions if they are less than the overflow
 			if size := uint64(list.Len()); size <= drop {
 				for _, tx := range list.Flatten() {
-					pool.removeTx(tx.Hash())
+					pool.removeTx(tx.Hash(), true)
 				}
 				drop -= size
 				queuedRateLimitCounter.Inc(int64(size))
@@ -1061,7 +1064,7 @@ func (pool *TxPool) promoteExecutables(accounts []common.Address) {
 			// Otherwise drop only last few transactions
 			txs := list.Flatten()
 			for i := len(txs) - 1; i >= 0 && drop > 0; i-- {
-				pool.removeTx(txs[i].Hash())
+				pool.removeTx(txs[i].Hash(), true)
 				drop--
 				queuedRateLimitCounter.Inc(1)
 			}
diff --git a/core/tx_pool_test.go b/core/tx_pool_test.go
index 1cf533aa6..0cb14cb6a 100644
--- a/core/tx_pool_test.go
+++ b/core/tx_pool_test.go
@@ -209,15 +209,10 @@ func TestStateChangeDuringTransactionPoolReset(t *testing.T) {
 
 	pool.lockedReset(nil, nil)
 
-	pendingTx, err := pool.Pending()
+	_, err := pool.Pending()
 	if err != nil {
 		t.Fatalf("Could not fetch pending transactions: %v", err)
 	}
-
-	for addr, txs := range pendingTx {
-		t.Logf("%0x: %d\n", addr, len(txs))
-	}
-
 	nonce = pool.State().GetNonce(address)
 	if nonce != 2 {
 		t.Fatalf("Invalid nonce, want 2, got %d", nonce)
@@ -350,7 +345,7 @@ func TestTransactionChainFork(t *testing.T) {
 	if _, err := pool.add(tx, false); err != nil {
 		t.Error("didn't expect error", err)
 	}
-	pool.removeTx(tx.Hash())
+	pool.removeTx(tx.Hash(), true)
 
 	// reset the pool's internal state
 	resetState()
@@ -1388,13 +1383,13 @@ func TestTransactionPoolUnderpricing(t *testing.T) {
 		t.Fatalf("adding underpriced pending transaction error mismatch: have %v, want %v", err, ErrUnderpriced)
 	}
 	// Ensure that adding high priced transactions drops cheap ones, but not own
-	if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(3), keys[1])); err != nil {
+	if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(3), keys[1])); err != nil { // +K1:0 => -K1:1 => Pend K0:0, K0:1, K1:0, K2:0; Que -
 		t.Fatalf("failed to add well priced transaction: %v", err)
 	}
-	if err := pool.AddRemote(pricedTransaction(2, 100000, big.NewInt(4), keys[1])); err != nil {
+	if err := pool.AddRemote(pricedTransaction(2, 100000, big.NewInt(4), keys[1])); err != nil { // +K1:2 => -K0:0 => Pend K1:0, K2:0; Que K0:1 K1:2
 		t.Fatalf("failed to add well priced transaction: %v", err)
 	}
-	if err := pool.AddRemote(pricedTransaction(3, 100000, big.NewInt(5), keys[1])); err != nil {
+	if err := pool.AddRemote(pricedTransaction(3, 100000, big.NewInt(5), keys[1])); err != nil { // +K1:3 => -K0:1 => Pend K1:0, K2:0; Que K1:2 K1:3
 		t.Fatalf("failed to add well priced transaction: %v", err)
 	}
 	pending, queued = pool.Stats()
@@ -1404,7 +1399,7 @@ func TestTransactionPoolUnderpricing(t *testing.T) {
 	if queued != 2 {
 		t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 2)
 	}
-	if err := validateEvents(events, 2); err != nil {
+	if err := validateEvents(events, 1); err != nil {
 		t.Fatalf("additional event firing failed: %v", err)
 	}
 	if err := validateTxPoolInternals(pool); err != nil {
@@ -1430,6 +1425,74 @@ func TestTransactionPoolUnderpricing(t *testing.T) {
 	}
 }
 
+// Tests that more expensive transactions push out cheap ones from the pool, but
+// without producing instability by creating gaps that start jumping transactions
+// back and forth between queued/pending.
+func TestTransactionPoolStableUnderpricing(t *testing.T) {
+	t.Parallel()
+
+	// Create the pool to test the pricing enforcement with
+	db, _ := ethdb.NewMemDatabase()
+	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db))
+	blockchain := &testBlockChain{statedb, 1000000, new(event.Feed)}
+
+	config := testTxPoolConfig
+	config.GlobalSlots = 128
+	config.GlobalQueue = 0
+
+	pool := NewTxPool(config, params.TestChainConfig, blockchain)
+	defer pool.Stop()
+
+	// Keep track of transaction events to ensure all executables get announced
+	events := make(chan TxPreEvent, 32)
+	sub := pool.txFeed.Subscribe(events)
+	defer sub.Unsubscribe()
+
+	// Create a number of test accounts and fund them
+	keys := make([]*ecdsa.PrivateKey, 2)
+	for i := 0; i < len(keys); i++ {
+		keys[i], _ = crypto.GenerateKey()
+		pool.currentState.AddBalance(crypto.PubkeyToAddress(keys[i].PublicKey), big.NewInt(1000000))
+	}
+	// Fill up the entire queue with the same transaction price points
+	txs := types.Transactions{}
+	for i := uint64(0); i < config.GlobalSlots; i++ {
+		txs = append(txs, pricedTransaction(i, 100000, big.NewInt(1), keys[0]))
+	}
+	pool.AddRemotes(txs)
+
+	pending, queued := pool.Stats()
+	if pending != int(config.GlobalSlots) {
+		t.Fatalf("pending transactions mismatched: have %d, want %d", pending, config.GlobalSlots)
+	}
+	if queued != 0 {
+		t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 0)
+	}
+	if err := validateEvents(events, int(config.GlobalSlots)); err != nil {
+		t.Fatalf("original event firing failed: %v", err)
+	}
+	if err := validateTxPoolInternals(pool); err != nil {
+		t.Fatalf("pool internal state corrupted: %v", err)
+	}
+	// Ensure that adding high priced transactions drops a cheap, but doesn't produce a gap
+	if err := pool.AddRemote(pricedTransaction(0, 100000, big.NewInt(3), keys[1])); err != nil {
+		t.Fatalf("failed to add well priced transaction: %v", err)
+	}
+	pending, queued = pool.Stats()
+	if pending != int(config.GlobalSlots) {
+		t.Fatalf("pending transactions mismatched: have %d, want %d", pending, config.GlobalSlots)
+	}
+	if queued != 0 {
+		t.Fatalf("queued transactions mismatched: have %d, want %d", queued, 0)
+	}
+	if err := validateEvents(events, 1); err != nil {
+		t.Fatalf("additional event firing failed: %v", err)
+	}
+	if err := validateTxPoolInternals(pool); err != nil {
+		t.Fatalf("pool internal state corrupted: %v", err)
+	}
+}
+
 // Tests that the pool rejects replacement transactions that don't meet the minimum
 // price bump required.
 func TestTransactionReplacement(t *testing.T) {