plugeth/trie/hasher.go
Qian Bin 65ed1a6871
rlp, trie: faster trie node encoding (#24126)
This change speeds up trie hashing and all other activities that require
RLP encoding of trie nodes by approximately 20%. The speedup is achieved by
avoiding reflection overhead during node encoding.

The interface type trie.node now contains a method 'encode' that works with
rlp.EncoderBuffer. Management of EncoderBuffers is left to calling code.
trie.hasher, which is pooled to avoid allocations, now maintains an
EncoderBuffer. This means memory resources related to trie node encoding
are tied to the hasher pool.

Co-authored-by: Felix Lange <fjl@twurst.com>
2022-03-09 14:45:17 +01:00

210 lines
6.4 KiB
Go

// Copyright 2019 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package trie
import (
"sync"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/rlp"
"golang.org/x/crypto/sha3"
)
// hasher is a type used for the trie Hash operation. A hasher has some
// internal preallocated temp space
type hasher struct {
sha crypto.KeccakState
tmp []byte
encbuf rlp.EncoderBuffer
parallel bool // Whether to use paralallel threads when hashing
}
// hasherPool holds pureHashers
var hasherPool = sync.Pool{
New: func() interface{} {
return &hasher{
tmp: make([]byte, 0, 550), // cap is as large as a full fullNode.
sha: sha3.NewLegacyKeccak256().(crypto.KeccakState),
encbuf: rlp.NewEncoderBuffer(nil),
}
},
}
func newHasher(parallel bool) *hasher {
h := hasherPool.Get().(*hasher)
h.parallel = parallel
return h
}
func returnHasherToPool(h *hasher) {
hasherPool.Put(h)
}
// hash collapses a node down into a hash node, also returning a copy of the
// original node initialized with the computed hash to replace the original one.
func (h *hasher) hash(n node, force bool) (hashed node, cached node) {
// Return the cached hash if it's available
if hash, _ := n.cache(); hash != nil {
return hash, n
}
// Trie not processed yet, walk the children
switch n := n.(type) {
case *shortNode:
collapsed, cached := h.hashShortNodeChildren(n)
hashed := h.shortnodeToHash(collapsed, force)
// We need to retain the possibly _not_ hashed node, in case it was too
// small to be hashed
if hn, ok := hashed.(hashNode); ok {
cached.flags.hash = hn
} else {
cached.flags.hash = nil
}
return hashed, cached
case *fullNode:
collapsed, cached := h.hashFullNodeChildren(n)
hashed = h.fullnodeToHash(collapsed, force)
if hn, ok := hashed.(hashNode); ok {
cached.flags.hash = hn
} else {
cached.flags.hash = nil
}
return hashed, cached
default:
// Value and hash nodes don't have children so they're left as were
return n, n
}
}
// hashShortNodeChildren collapses the short node. The returned collapsed node
// holds a live reference to the Key, and must not be modified.
// The cached
func (h *hasher) hashShortNodeChildren(n *shortNode) (collapsed, cached *shortNode) {
// Hash the short node's child, caching the newly hashed subtree
collapsed, cached = n.copy(), n.copy()
// Previously, we did copy this one. We don't seem to need to actually
// do that, since we don't overwrite/reuse keys
//cached.Key = common.CopyBytes(n.Key)
collapsed.Key = hexToCompact(n.Key)
// Unless the child is a valuenode or hashnode, hash it
switch n.Val.(type) {
case *fullNode, *shortNode:
collapsed.Val, cached.Val = h.hash(n.Val, false)
}
return collapsed, cached
}
func (h *hasher) hashFullNodeChildren(n *fullNode) (collapsed *fullNode, cached *fullNode) {
// Hash the full node's children, caching the newly hashed subtrees
cached = n.copy()
collapsed = n.copy()
if h.parallel {
var wg sync.WaitGroup
wg.Add(16)
for i := 0; i < 16; i++ {
go func(i int) {
hasher := newHasher(false)
if child := n.Children[i]; child != nil {
collapsed.Children[i], cached.Children[i] = hasher.hash(child, false)
} else {
collapsed.Children[i] = nilValueNode
}
returnHasherToPool(hasher)
wg.Done()
}(i)
}
wg.Wait()
} else {
for i := 0; i < 16; i++ {
if child := n.Children[i]; child != nil {
collapsed.Children[i], cached.Children[i] = h.hash(child, false)
} else {
collapsed.Children[i] = nilValueNode
}
}
}
return collapsed, cached
}
// shortnodeToHash creates a hashNode from a shortNode. The supplied shortnode
// should have hex-type Key, which will be converted (without modification)
// into compact form for RLP encoding.
// If the rlp data is smaller than 32 bytes, `nil` is returned.
func (h *hasher) shortnodeToHash(n *shortNode, force bool) node {
n.encode(h.encbuf)
enc := h.encodedBytes()
if len(enc) < 32 && !force {
return n // Nodes smaller than 32 bytes are stored inside their parent
}
return h.hashData(enc)
}
// shortnodeToHash is used to creates a hashNode from a set of hashNodes, (which
// may contain nil values)
func (h *hasher) fullnodeToHash(n *fullNode, force bool) node {
n.encode(h.encbuf)
enc := h.encodedBytes()
if len(enc) < 32 && !force {
return n // Nodes smaller than 32 bytes are stored inside their parent
}
return h.hashData(enc)
}
// encodedBytes returns the result of the last encoding operation on h.encbuf.
// This also resets the encoder buffer.
//
// All node encoding must be done like this:
//
// node.encode(h.encbuf)
// enc := h.encodedBytes()
//
// This convention exists because node.encode can only be inlined/escape-analyzed when
// called on a concrete receiver type.
func (h *hasher) encodedBytes() []byte {
h.tmp = h.encbuf.AppendToBytes(h.tmp[:0])
h.encbuf.Reset(nil)
return h.tmp
}
// hashData hashes the provided data
func (h *hasher) hashData(data []byte) hashNode {
n := make(hashNode, 32)
h.sha.Reset()
h.sha.Write(data)
h.sha.Read(n)
return n
}
// proofHash is used to construct trie proofs, and returns the 'collapsed'
// node (for later RLP encoding) aswell as the hashed node -- unless the
// node is smaller than 32 bytes, in which case it will be returned as is.
// This method does not do anything on value- or hash-nodes.
func (h *hasher) proofHash(original node) (collapsed, hashed node) {
switch n := original.(type) {
case *shortNode:
sn, _ := h.hashShortNodeChildren(n)
return sn, h.shortnodeToHash(sn, false)
case *fullNode:
fn, _ := h.hashFullNodeChildren(n)
return fn, h.fullnodeToHash(fn, false)
default:
// Value and hash nodes don't have children so they're left as were
return n, n
}
}