EIP-1559 tx pool support

core/tx_list.go

@@ -21,6 +21,7 @@ import (
 	"math"
 	"math/big"
 	"sort"
+	"time"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -279,15 +280,23 @@ func (l *txList) Add(tx *types.Transaction, priceBump uint64) (bool, *types.Tran
 	// If there's an older better transaction, abort
 	old := l.txs.Get(tx.Nonce())
 	if old != nil {
-		// threshold = oldGP * (100 + priceBump) / 100
+		if old.FeeCapCmp(tx) >= 0 || old.TipCmp(tx) >= 0 {
+			return false, nil
+		}
+		// thresholdFeeCap = oldFC  * (100 + priceBump) / 100
 		a := big.NewInt(100 + int64(priceBump))
-		a = a.Mul(a, old.GasPrice())
+		aFeeCap := new(big.Int).Mul(a, old.FeeCap())
+		aTip := a.Mul(a, old.Tip())
+
+		// thresholdTip    = oldTip * (100 + priceBump) / 100
 		b := big.NewInt(100)
-		threshold := a.Div(a, b)
-		// Have to ensure that the new gas price is higher than the old gas
-		// price as well as checking the percentage threshold to ensure that
+		thresholdFeeCap := aFeeCap.Div(aFeeCap, b)
+		thresholdTip := aTip.Div(aTip, b)
+
+		// Have to ensure that either the new fee cap or tip is higher than the
+		// old ones as well as checking the percentage threshold to ensure that
 		// this is accurate for low (Wei-level) gas price replacements
-		if old.GasPriceCmp(tx) >= 0 || tx.GasPriceIntCmp(threshold) < 0 {
+		if tx.FeeCapIntCmp(thresholdFeeCap) < 0 || tx.TipIntCmp(thresholdTip) < 0 {
 			return false, nil
 		}
 	}
@@ -406,52 +415,84 @@ func (l *txList) LastElement() *types.Transaction {
 }
 
 // priceHeap is a heap.Interface implementation over transactions for retrieving
-// price-sorted transactions to discard when the pool fills up.
-type priceHeap []*types.Transaction
+// price-sorted transactions to discard when the pool fills up. If baseFee is set
+// then the heap is sorted based on the effective tip based on the given base fee.
+// If baseFee is nil then the sorting is based on feeCap.
+type priceHeap struct {
+	baseFee *big.Int // heap should always be re-sorted after baseFee is changed
+	list    []*types.Transaction
+}
 
-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) Len() int      { return len(h.list) }
+func (h *priceHeap) Swap(i, j int) { h.list[i], h.list[j] = h.list[j], h.list[i] }
 
-func (h priceHeap) Less(i, j int) bool {
-	// Sort primarily by price, returning the cheaper one
-	switch h[i].GasPriceCmp(h[j]) {
+func (h *priceHeap) Less(i, j int) bool {
+	switch h.cmp(h.list[i], h.list[j]) {
 	case -1:
 		return true
 	case 1:
 		return false
+	default:
+		return h.list[i].Nonce() > h.list[j].Nonce()
 	}
-	// If the prices match, stabilize via nonces (high nonce is worse)
-	return h[i].Nonce() > h[j].Nonce()
+}
+
+func (h *priceHeap) cmp(a, b *types.Transaction) int {
+	if h.baseFee != nil {
+		// Compare effective tips if baseFee is specified
+		if c := a.EffectiveTipCmp(b, h.baseFee); c != 0 {
+			return c
+		}
+	}
+	// Compare fee caps if baseFee is not specified or effective tips are equal
+	if c := a.FeeCapCmp(b); c != 0 {
+		return c
+	}
+	// Compare tips if effective tips and fee caps are equal
+	return a.TipCmp(b)
 }
 
 func (h *priceHeap) Push(x interface{}) {
-	*h = append(*h, x.(*types.Transaction))
+	tx := x.(*types.Transaction)
+	h.list = append(h.list, tx)
 }
 
 func (h *priceHeap) Pop() interface{} {
-	old := *h
+	old := h.list
 	n := len(old)
 	x := old[n-1]
 	old[n-1] = nil
-	*h = old[0 : n-1]
+	h.list = old[0 : n-1]
 	return x
 }
 
 // txPricedList is a price-sorted heap to allow operating on transactions pool
 // contents in a price-incrementing way. It's built opon the all transactions
 // in txpool but only interested in the remote part. It means only remote transactions
 // will be considered for tracking, sorting, eviction, etc.
+//
+// Two heaps are used for sorting: the urgent heap (based on effective tip in the next
+// block) and the floating heap (based on feeCap). Always the bigger heap is chosen for
+// eviction. Transactions evicted from the urgent heap are first demoted into the floating heap.
+// In some cases (during a congestion, when blocks are full) the urgent heap can provide
+// better candidates for inclusion while in other cases (at the top of the baseFee peak)
+// the floating heap is better. When baseFee is decreasing they behave similarly.
 type txPricedList struct {
-	all     *txLookup  // Pointer to the map of all transactions
-	remotes *priceHeap // Heap of prices of all the stored **remote** transactions
-	stales  int        // Number of stale price points to (re-heap trigger)
+	all              *txLookup // Pointer to the map of all transactions
+	urgent, floating priceHeap // Heaps of prices of all the stored **remote** transactions
+	stales           int       // Number of stale price points to (re-heap trigger)
 }
 
+const (
+	// urgentRatio : floatingRatio is the capacity ratio of the two queues
+	urgentRatio   = 4
+	floatingRatio = 1
+)
+
 // newTxPricedList creates a new price-sorted transaction heap.
 func newTxPricedList(all *txLookup) *txPricedList {
 	return &txPricedList{
-		all:     all,
-		remotes: new(priceHeap),
+		all: all,
 	}
 }
 
@@ -460,7 +501,8 @@ func (l *txPricedList) Put(tx *types.Transaction, local bool) {
 	if local {
 		return
 	}
-	heap.Push(l.remotes, tx)
+	// Insert every new transaction to the urgent heap first; Discard will balance the heaps
+	heap.Push(&l.urgent, tx)
 }
 
 // Removed notifies the prices transaction list that an old transaction dropped
@@ -469,58 +511,42 @@ func (l *txPricedList) Put(tx *types.Transaction, local bool) {
 func (l *txPricedList) Removed(count int) {
 	// Bump the stale counter, but exit if still too low (< 25%)
 	l.stales += count
-	if l.stales <= len(*l.remotes)/4 {
+	if l.stales <= (len(l.urgent.list)+len(l.floating.list))/4 {
 		return
 	}
 	// Seems we've reached a critical number of stale transactions, reheap
 	l.Reheap()
 }
 
-// Cap finds all the transactions below the given price threshold, drops them
-// from the priced list and returns them for further removal from the entire pool.
-//
-// Note: only remote transactions will be considered for eviction.
-func (l *txPricedList) Cap(threshold *big.Int) types.Transactions {
-	drop := make(types.Transactions, 0, 128) // Remote underpriced transactions to drop
-	for len(*l.remotes) > 0 {
-		// Discard stale transactions if found during cleanup
-		cheapest := (*l.remotes)[0]
-		if l.all.GetRemote(cheapest.Hash()) == nil { // Removed or migrated
-			heap.Pop(l.remotes)
-			l.stales--
-			continue
-		}
-		// Stop the discards if we've reached the threshold
-		if cheapest.GasPriceIntCmp(threshold) >= 0 {
-			break
-		}
-		heap.Pop(l.remotes)
-		drop = append(drop, cheapest)
-	}
-	return drop
-}
-
 // Underpriced checks whether a transaction is cheaper than (or as cheap as) the
 // lowest priced (remote) transaction currently being tracked.
 func (l *txPricedList) Underpriced(tx *types.Transaction) bool {
+	return l.underpricedFor(&l.urgent, tx) && l.underpricedFor(&l.floating, tx)
+}
+
+// underpricedFor checks whether a transaction is cheaper than (or as cheap as) the
+// lowest priced (remote) transaction in the given heap.
+func (l *txPricedList) underpricedFor(h *priceHeap, tx *types.Transaction) bool {
 	// Discard stale price points if found at the heap start
-	for len(*l.remotes) > 0 {
-		head := []*types.Transaction(*l.remotes)[0]
+	for len(h.list) > 0 {
+		head := h.list[0]
 		if l.all.GetRemote(head.Hash()) == nil { // Removed or migrated
 			l.stales--
-			heap.Pop(l.remotes)
+			heap.Pop(h)
 			continue
 		}
 		break
 	}
 	// Check if the transaction is underpriced or not
-	if len(*l.remotes) == 0 {
-		return false // There is no remote transaction at all.
+	if len(h.list) == 0 {
+		// Note: since Underpriced is only called when the pool is full, this case is only
+		// possible if one of the queues has a zero capacity. In this case we should report
+		// that the transaction in question will not fit in this queue.
+		return true // There is no remote transaction at all.
 	}
 	// If the remote transaction is even cheaper than the
 	// cheapest one tracked locally, reject it.
-	cheapest := []*types.Transaction(*l.remotes)[0]
-	return cheapest.GasPriceCmp(tx) >= 0
+	return h.cmp(h.list[0], tx) >= 0
 }
 
 // Discard finds a number of most underpriced transactions, removes them from the
@@ -529,21 +555,36 @@ func (l *txPricedList) Underpriced(tx *types.Transaction) bool {
 // Note local transaction won't be considered for eviction.
 func (l *txPricedList) Discard(slots int, force bool) (types.Transactions, bool) {
 	drop := make(types.Transactions, 0, slots) // Remote underpriced transactions to drop
-	for len(*l.remotes) > 0 && slots > 0 {
-		// Discard stale transactions if found during cleanup
-		tx := heap.Pop(l.remotes).(*types.Transaction)
-		if l.all.GetRemote(tx.Hash()) == nil { // Removed or migrated
-			l.stales--
-			continue
+	for slots > 0 {
+		if len(l.urgent.list)*floatingRatio > len(l.floating.list)*urgentRatio || floatingRatio == 0 {
+			// Discard stale transactions if found during cleanup
+			tx := heap.Pop(&l.urgent).(*types.Transaction)
+			if l.all.GetRemote(tx.Hash()) == nil { // Removed or migrated
+				l.stales--
+				continue
+			}
+			// Non stale transaction found, move to floating heap
+			heap.Push(&l.floating, tx)
+		} else {
+			if len(l.floating.list) == 0 {
+				// Stop if both heaps are empty
+				break
+			}
+			// Discard stale transactions if found during cleanup
+			tx := heap.Pop(&l.floating).(*types.Transaction)
+			if l.all.GetRemote(tx.Hash()) == nil { // Removed or migrated
+				l.stales--
+				continue
+			}
+			// Non stale transaction found, discard it
+			drop = append(drop, tx)
+			slots -= numSlots(tx)
 		}
-		// Non stale transaction found, discard it
-		drop = append(drop, tx)
-		slots -= numSlots(tx)
 	}
 	// If we still can't make enough room for the new transaction
 	if slots > 0 && !force {
 		for _, tx := range drop {
-			heap.Push(l.remotes, tx)
+			heap.Push(&l.urgent, tx)
 		}
 		return nil, false
 	}
@@ -552,12 +593,32 @@ func (l *txPricedList) Discard(slots int, force bool) (types.Transactions, bool)
 
 // Reheap forcibly rebuilds the heap based on the current remote transaction set.
 func (l *txPricedList) Reheap() {
-	reheap := make(priceHeap, 0, l.all.RemoteCount())
-
-	l.stales, l.remotes = 0, &reheap
+	start := time.Now()
+	l.stales = 0
+	l.urgent.list = make([]*types.Transaction, 0, l.all.RemoteCount())
 	l.all.Range(func(hash common.Hash, tx *types.Transaction, local bool) bool {
-		*l.remotes = append(*l.remotes, tx)
+		l.urgent.list = append(l.urgent.list, tx)
 		return true
 	}, false, true) // Only iterate remotes
-	heap.Init(l.remotes)
+	heap.Init(&l.urgent)
+
+	// balance out the two heaps by moving the worse half of transactions into the
+	// floating heap
+	// Note: Discard would also do this before the first eviction but Reheap can do
+	// is more efficiently. Also, Underpriced would work suboptimally the first time
+	// if the floating queue was empty.
+	floatingCount := len(l.urgent.list) * floatingRatio / (urgentRatio + floatingRatio)
+	l.floating.list = make([]*types.Transaction, floatingCount)
+	for i := 0; i < floatingCount; i++ {
+		l.floating.list[i] = heap.Pop(&l.urgent).(*types.Transaction)
+	}
+	heap.Init(&l.floating)
+	reheapTimer.Update(time.Since(start))
+}
+
+// SetBaseFee updates the base fee and triggers a re-heap. Note that Removed is not
+// necessary to call right before SetBaseFee when processing a new block.
+func (l *txPricedList) SetBaseFee(baseFee *big.Int) {
+	l.urgent.baseFee = baseFee
+	l.Reheap()
 }