consensus/clique: cache block signatures for fast checks

Author: karalabe

consensus/clique/clique.go

@@ -44,7 +44,7 @@ import (
 const (
 	checkpointInterval = 1024 // Number of blocks after which to save the vote snapshot to the database
 	inmemorySnapshots  = 128  // Number of recent vote snapshots to keep in memory
-	inmemorySignatures = 1024 // Number of recent blocks to keep in memory
+	inmemorySignatures = 4096 // Number of recent block signatures to keep in memory
 
 	wiggleTime = 500 * time.Millisecond // Random delay (per signer) to allow concurrent signers
 )
@@ -162,7 +162,12 @@ func sigHash(header *types.Header) (hash common.Hash) {
 }
 
 // ecrecover extracts the Ethereum account address from a signed header.
-func ecrecover(header *types.Header) (common.Address, error) {
+func ecrecover(header *types.Header, sigcache *lru.ARCCache) (common.Address, error) {
+	// If the signature's already cached, return that
+	hash := header.Hash()
+	if address, known := sigcache.Get(hash); known {
+		return address.(common.Address), nil
+	}
 	// Retrieve the signature from the header extra-data
 	if len(header.Extra) < extraSeal {
 		return common.Address{}, errMissingSignature
@@ -177,6 +182,7 @@ func ecrecover(header *types.Header) (common.Address, error) {
 	var signer common.Address
 	copy(signer[:], crypto.Keccak256(pubkey[1:])[12:])
 
+	sigcache.Add(hash, signer)
 	return signer, nil
 }
 
@@ -223,7 +229,7 @@ func New(config *params.CliqueConfig, db ethdb.Database) *Clique {
 // Author implements consensus.Engine, returning the Ethereum address recovered
 // from the signature in the header's extra-data section.
 func (c *Clique) Author(header *types.Header) (common.Address, error) {
-	return ecrecover(header)
+	return ecrecover(header, c.signatures)
 }
 
 // VerifyHeader checks whether a header conforms to the consensus rules.
@@ -369,7 +375,7 @@ func (c *Clique) snapshot(chain consensus.ChainReader, number uint64, hash commo
 		}
 		// If an on-disk checkpoint snapshot can be found, use that
 		if number%checkpointInterval == 0 {
-			if s, err := loadSnapshot(c.config, c.db, hash); err == nil {
+			if s, err := loadSnapshot(c.config, c.signatures, c.db, hash); err == nil {
 				log.Trace("Loaded voting snapshot form disk", "number", number, "hash", hash)
 				snap = s
 				break
@@ -385,7 +391,7 @@ func (c *Clique) snapshot(chain consensus.ChainReader, number uint64, hash commo
 			for i := 0; i < len(signers); i++ {
 				copy(signers[i][:], genesis.Extra[extraVanity+i*common.AddressLength:])
 			}
-			snap = newSnapshot(c.config, 0, genesis.Hash(), signers)
+			snap = newSnapshot(c.config, c.signatures, 0, genesis.Hash(), signers)
 			if err := snap.store(c.db); err != nil {
 				return nil, err
 			}
@@ -464,7 +470,7 @@ func (c *Clique) verifySeal(chain consensus.ChainReader, header *types.Header, p
 	c.recents.Add(snap.Hash, snap)
 
 	// Resolve the authorization key and check against signers
-	signer, err := ecrecover(header)
+	signer, err := ecrecover(header, c.signatures)
 	if err != nil {
 		return err
 	}

consensus/clique/snapshot.go

@@ -24,6 +24,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/params"
+	lru "github.com/hashicorp/golang-lru"
 )
 
 // Vote represents a single vote that an authorized signer made to modify the
@@ -44,7 +45,8 @@ type Tally struct {
 
 // Snapshot is the state of the authorization voting at a given point in time.
 type Snapshot struct {
-	config *params.CliqueConfig // Consensus engine parameters to fine tune behavior
+	config   *params.CliqueConfig // Consensus engine parameters to fine tune behavior
+	sigcache *lru.ARCCache        // Cache of recent block signatures to speed up ecrecover
 
 	Number  uint64                      `json:"number"`  // Block number where the snapshot was created
 	Hash    common.Hash                 `json:"hash"`    // Block hash where the snapshot was created
@@ -57,14 +59,15 @@ type Snapshot struct {
 // newSnapshot create a new snapshot with the specified startup parameters. This
 // method does not initialize the set of recent signers, so only ever use if for
 // the genesis block.
-func newSnapshot(config *params.CliqueConfig, number uint64, hash common.Hash, signers []common.Address) *Snapshot {
+func newSnapshot(config *params.CliqueConfig, sigcache *lru.ARCCache, number uint64, hash common.Hash, signers []common.Address) *Snapshot {
 	snap := &Snapshot{
-		config:  config,
-		Number:  number,
-		Hash:    hash,
-		Signers: make(map[common.Address]struct{}),
-		Recents: make(map[uint64]common.Address),
-		Tally:   make(map[common.Address]Tally),
+		config:   config,
+		sigcache: sigcache,
+		Number:   number,
+		Hash:     hash,
+		Signers:  make(map[common.Address]struct{}),
+		Recents:  make(map[uint64]common.Address),
+		Tally:    make(map[common.Address]Tally),
 	}
 	for _, signer := range signers {
 		snap.Signers[signer] = struct{}{}
@@ -73,7 +76,7 @@ func newSnapshot(config *params.CliqueConfig, number uint64, hash common.Hash, s
 }
 
 // loadSnapshot loads an existing snapshot from the database.
-func loadSnapshot(config *params.CliqueConfig, db ethdb.Database, hash common.Hash) (*Snapshot, error) {
+func loadSnapshot(config *params.CliqueConfig, sigcache *lru.ARCCache, db ethdb.Database, hash common.Hash) (*Snapshot, error) {
 	blob, err := db.Get(append([]byte("clique-"), hash[:]...))
 	if err != nil {
 		return nil, err
@@ -83,6 +86,7 @@ func loadSnapshot(config *params.CliqueConfig, db ethdb.Database, hash common.Ha
 		return nil, err
 	}
 	snap.config = config
+	snap.sigcache = sigcache
 
 	return snap, nil
 }
@@ -99,13 +103,14 @@ func (s *Snapshot) store(db ethdb.Database) error {
 // copy creates a deep copy of the snapshot, though not the individual votes.
 func (s *Snapshot) copy() *Snapshot {
 	cpy := &Snapshot{
-		config:  s.config,
-		Number:  s.Number,
-		Hash:    s.Hash,
-		Signers: make(map[common.Address]struct{}),
-		Recents: make(map[uint64]common.Address),
-		Votes:   make([]*Vote, len(s.Votes)),
-		Tally:   make(map[common.Address]Tally),
+		config:   s.config,
+		sigcache: s.sigcache,
+		Number:   s.Number,
+		Hash:     s.Hash,
+		Signers:  make(map[common.Address]struct{}),
+		Recents:  make(map[uint64]common.Address),
+		Votes:    make([]*Vote, len(s.Votes)),
+		Tally:    make(map[common.Address]Tally),
 	}
 	for signer := range s.Signers {
 		cpy.Signers[signer] = struct{}{}
@@ -190,7 +195,7 @@ func (s *Snapshot) apply(headers []*types.Header) (*Snapshot, error) {
 			delete(snap.Recents, number-limit)
 		}
 		// Resolve the authorization key and check against signers
-		signer, err := ecrecover(header)
+		signer, err := ecrecover(header, s.sigcache)
 		if err != nil {
 			return nil, err
 		}