core: improve trie updates (part 2)

accounts/abi/bind/backends/simulated.go

@@ -125,10 +125,9 @@ func (b *SimulatedBackend) Rollback() {
 
 func (b *SimulatedBackend) rollback() {
 	blocks, _ := core.GenerateChain(b.config, b.blockchain.CurrentBlock(), ethash.NewFaker(), b.database, 1, func(int, *core.BlockGen) {})
-	stateDB, _ := b.blockchain.State()
 
 	b.pendingBlock = blocks[0]
-	b.pendingState, _ = state.New(b.pendingBlock.Root(), stateDB.Database(), nil)
+	b.pendingState, _ = state.New(b.pendingBlock.Root(), b.blockchain.StateCache(), nil)
 }
 
 // stateByBlockNumber retrieves a state by a given blocknumber.

core/blockchain.go

@@ -202,9 +202,9 @@ type BlockChain struct {
 	procInterrupt int32          // interrupt signaler for block processing
 
 	engine     consensus.Engine
-	validator  Validator  // Block and state validator interface
-	prefetcher Prefetcher // Block state prefetcher interface
-	processor  Processor  // Block transaction processor interface
+	validator  Validator // Block and state validator interface
+	prefetcher Prefetcher
+	processor  Processor // Block transaction processor interface
 	vmConfig   vm.Config
 
 	shouldPreserve     func(*types.Block) bool        // Function used to determine whether should preserve the given block.
@@ -1860,12 +1860,17 @@ func (bc *BlockChain) insertChain(chain types.Blocks, verifySeals bool) (int, er
 		if err != nil {
 			return it.index, err
 		}
+		// Enable prefetching to pull in trie node paths while processing transactions
+		statedb.StartPrefetcher("chain")
+		defer statedb.StopPrefetcher() // stopped on write anyway, defer meant to catch early error returns
+
 		// If we have a followup block, run that against the current state to pre-cache
 		// transactions and probabilistically some of the account/storage trie nodes.
 		var followupInterrupt uint32
 		if !bc.cacheConfig.TrieCleanNoPrefetch {
 			if followup, err := it.peek(); followup != nil && err == nil {
 				throwaway, _ := state.New(parent.Root, bc.stateCache, bc.snaps)
+
 				go func(start time.Time, followup *types.Block, throwaway *state.StateDB, interrupt *uint32) {
 					bc.prefetcher.Prefetch(followup, throwaway, bc.vmConfig, &followupInterrupt)
 
@@ -1891,8 +1896,7 @@ func (bc *BlockChain) insertChain(chain types.Blocks, verifySeals bool) (int, er
 		storageUpdateTimer.Update(statedb.StorageUpdates)             // Storage updates are complete, we can mark them
 		snapshotAccountReadTimer.Update(statedb.SnapshotAccountReads) // Account reads are complete, we can mark them
 		snapshotStorageReadTimer.Update(statedb.SnapshotStorageReads) // Storage reads are complete, we can mark them
-
-		triehash := statedb.AccountHashes + statedb.StorageHashes // Save to not double count in validation
+		triehash := statedb.AccountHashes + statedb.StorageHashes     // Save to not double count in validation
 		trieproc := statedb.SnapshotAccountReads + statedb.AccountReads + statedb.AccountUpdates
 		trieproc += statedb.SnapshotStorageReads + statedb.StorageReads + statedb.StorageUpdates
 
@@ -1920,7 +1924,6 @@ func (bc *BlockChain) insertChain(chain types.Blocks, verifySeals bool) (int, er
 		if err != nil {
 			return it.index, err
 		}
-
 		// Update the metrics touched during block commit
 		accountCommitTimer.Update(statedb.AccountCommits)   // Account commits are complete, we can mark them
 		storageCommitTimer.Update(statedb.StorageCommits)   // Storage commits are complete, we can mark them

core/state/database.go

@@ -129,12 +129,20 @@ type cachingDB struct {
 
 // OpenTrie opens the main account trie at a specific root hash.
 func (db *cachingDB) OpenTrie(root common.Hash) (Trie, error) {
-	return trie.NewSecure(root, db.db)
+	tr, err := trie.NewSecure(root, db.db)
+	if err != nil {
+		return nil, err
+	}
+	return tr, nil
 }
 
 // OpenStorageTrie opens the storage trie of an account.
 func (db *cachingDB) OpenStorageTrie(addrHash, root common.Hash) (Trie, error) {
-	return trie.NewSecure(root, db.db)
+	tr, err := trie.NewSecure(root, db.db)
+	if err != nil {
+		return nil, err
+	}
+	return tr, nil
 }
 
 // CopyTrie returns an independent copy of the given trie.

core/state/state_object.go

@@ -157,11 +157,20 @@ func (s *stateObject) touch() {
 
 func (s *stateObject) getTrie(db Database) Trie {
 	if s.trie == nil {
-		var err error
-		s.trie, err = db.OpenStorageTrie(s.addrHash, s.data.Root)
-		if err != nil {
-			s.trie, _ = db.OpenStorageTrie(s.addrHash, common.Hash{})
-			s.setError(fmt.Errorf("can't create storage trie: %v", err))
+		// Try fetching from prefetcher first
+		// We don't prefetch empty tries
+		if s.data.Root != emptyRoot && s.db.prefetcher != nil {
+			// When the miner is creating the pending state, there is no
+			// prefetcher
+			s.trie = s.db.prefetcher.trie(s.data.Root)
+		}
+		if s.trie == nil {
+			var err error
+			s.trie, err = db.OpenStorageTrie(s.addrHash, s.data.Root)
+			if err != nil {
+				s.trie, _ = db.OpenStorageTrie(s.addrHash, common.Hash{})
+				s.setError(fmt.Errorf("can't create storage trie: %v", err))
+			}
 		}
 	}
 	return s.trie
@@ -197,12 +206,24 @@ func (s *stateObject) GetCommittedState(db Database, key common.Hash) common.Has
 	}
 	// If no live objects are available, attempt to use snapshots
 	var (
-		enc []byte
-		err error
+		enc   []byte
+		err   error
+		meter *time.Duration
 	)
+	readStart := time.Now()
+	if metrics.EnabledExpensive {
+		// If the snap is 'under construction', the first lookup may fail. If that
+		// happens, we don't want to double-count the time elapsed. Thus this
+		// dance with the metering.
+		defer func() {
+			if meter != nil {
+				*meter += time.Since(readStart)
+			}
+		}()
+	}
 	if s.db.snap != nil {
 		if metrics.EnabledExpensive {
-			defer func(start time.Time) { s.db.SnapshotStorageReads += time.Since(start) }(time.Now())
+			meter = &s.db.SnapshotStorageReads
 		}
 		// If the object was destructed in *this* block (and potentially resurrected),
 		// the storage has been cleared out, and we should *not* consult the previous
@@ -217,8 +238,14 @@ func (s *stateObject) GetCommittedState(db Database, key common.Hash) common.Has
 	}
 	// If snapshot unavailable or reading from it failed, load from the database
 	if s.db.snap == nil || err != nil {
+		if meter != nil {
+			// If we already spent time checking the snapshot, account for it
+			// and reset the readStart
+			*meter += time.Since(readStart)
+			readStart = time.Now()
+		}
 		if metrics.EnabledExpensive {
-			defer func(start time.Time) { s.db.StorageReads += time.Since(start) }(time.Now())
+			meter = &s.db.StorageReads
 		}
 		if enc, err = s.getTrie(db).TryGet(key.Bytes()); err != nil {
 			s.setError(err)
@@ -282,9 +309,16 @@ func (s *stateObject) setState(key, value common.Hash) {
 
 // finalise moves all dirty storage slots into the pending area to be hashed or
 // committed later. It is invoked at the end of every transaction.
-func (s *stateObject) finalise() {
+func (s *stateObject) finalise(prefetch bool) {
+	slotsToPrefetch := make([][]byte, 0, len(s.dirtyStorage))
 	for key, value := range s.dirtyStorage {
 		s.pendingStorage[key] = value
+		if value != s.originStorage[key] {
+			slotsToPrefetch = append(slotsToPrefetch, common.CopyBytes(key[:])) // Copy needed for closure
+		}
+	}
+	if s.db.prefetcher != nil && prefetch && len(slotsToPrefetch) > 0 && s.data.Root != emptyRoot {
+		s.db.prefetcher.prefetch(s.data.Root, slotsToPrefetch)
 	}
 	if len(s.dirtyStorage) > 0 {
 		s.dirtyStorage = make(Storage)
@@ -295,26 +329,21 @@ func (s *stateObject) finalise() {
 // It will return nil if the trie has not been loaded and no changes have been made
 func (s *stateObject) updateTrie(db Database) Trie {
 	// Make sure all dirty slots are finalized into the pending storage area
-	s.finalise()
+	s.finalise(false) // Don't prefetch any more, pull directly if need be
 	if len(s.pendingStorage) == 0 {
 		return s.trie
 	}
 	// Track the amount of time wasted on updating the storage trie
 	if metrics.EnabledExpensive {
 		defer func(start time.Time) { s.db.StorageUpdates += time.Since(start) }(time.Now())
 	}
-	// Retrieve the snapshot storage map for the object
+	// The snapshot storage map for the object
 	var storage map[common.Hash][]byte
-	if s.db.snap != nil {
-		// Retrieve the old storage map, if available, create a new one otherwise
-		storage = s.db.snapStorage[s.addrHash]
-		if storage == nil {
-			storage = make(map[common.Hash][]byte)
-			s.db.snapStorage[s.addrHash] = storage
-		}
-	}
 	// Insert all the pending updates into the trie
 	tr := s.getTrie(db)
+	hasher := s.db.hasher
+
+	usedStorage := make([][]byte, 0, len(s.pendingStorage))
 	for key, value := range s.pendingStorage {
 		// Skip noop changes, persist actual changes
 		if value == s.originStorage[key] {
@@ -331,9 +360,20 @@ func (s *stateObject) updateTrie(db Database) Trie {
 			s.setError(tr.TryUpdate(key[:], v))
 		}
 		// If state snapshotting is active, cache the data til commit
-		if storage != nil {
-			storage[crypto.Keccak256Hash(key[:])] = v // v will be nil if value is 0x00
+		if s.db.snap != nil {
+			if storage == nil {
+				// Retrieve the old storage map, if available, create a new one otherwise
+				if storage = s.db.snapStorage[s.addrHash]; storage == nil {
+					storage = make(map[common.Hash][]byte)
+					s.db.snapStorage[s.addrHash] = storage
+				}
+			}
+			storage[crypto.HashData(hasher, key[:])] = v // v will be nil if value is 0x00
 		}
+		usedStorage = append(usedStorage, common.CopyBytes(key[:])) // Copy needed for closure
+	}
+	if s.db.prefetcher != nil {
+		s.db.prefetcher.used(s.data.Root, usedStorage)
 	}
 	if len(s.pendingStorage) > 0 {
 		s.pendingStorage = make(Storage)

core/state/state_test.go

@@ -170,7 +170,7 @@ func TestSnapshot2(t *testing.T) {
 	state.setStateObject(so0)
 
 	root, _ := state.Commit(false)
-	state.Reset(root)
+	state, _ = New(root, state.db, state.snaps)
 
 	// and one with deleted == true
 	so1 := state.getStateObject(stateobjaddr1)