forks/go-ethereum
1
0
Fork 1
mirror of https://github.com/ethereum/go-ethereum.git synced 2026-08-17 01:13:45 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

consensus/ethash: add maxEpoch constant

Browse source
This commit is contained in:
Felix Lange 2018-01-11 15:33:35 +01:00
parent b06e20bc7c
commit 6abad68f82
5 changed files with 23 additions and 23 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
consensus/ethash/algorithm.go
View file

@ -355,9 +355,11 @@ func hashimotoFull(dataset []uint32, hash []byte, nonce uint64) ([]byte, []byte)
return hashimoto(hash, nonce, uint64(len(dataset))*4, lookup)
}
const maxEpoch = 2048
// datasetSizes is a lookup table for the ethash dataset size for the first 2048
// epochs (i.e. 61440000 blocks).
var datasetSizes = []uint64{
var datasetSizes = [maxEpoch]uint64{
1073739904, 1082130304, 1090514816, 1098906752, 1107293056,
1115684224, 1124070016, 1132461952, 1140849536, 1149232768,
1157627776, 1166013824, 1174404736, 1182786944, 1191180416,
@ -771,7 +773,7 @@ var datasetSizes = []uint64{
// cacheSizes is a lookup table for the ethash verification cache size for the
// first 2048 epochs (i.e. 61440000 blocks).
var cacheSizes = []uint64{
var cacheSizes = [maxEpoch]uint64{
16776896, 16907456, 17039296, 17170112, 17301056, 17432512, 17563072,
17693888, 17824192, 17955904, 18087488, 18218176, 18349504, 18481088,
18611392, 18742336, 18874304, 19004224, 19135936, 19267264, 19398208,

4
consensus/ethash/algorithm_go1.7.go
View file

@ -25,7 +25,7 @@ package ethash
func cacheSize(block uint64) uint64 {
// If we have a pre-generated value, use that
epoch := int(block / epochLength)
if epoch < len(cacheSizes) {
if epoch < maxEpoch {
return cacheSizes[epoch]
}
// We don't have a way to verify primes fast before Go 1.8
@ -39,7 +39,7 @@ func cacheSize(block uint64) uint64 {
func datasetSize(block uint64) uint64 {
// If we have a pre-generated value, use that
epoch := int(block / epochLength)
if epoch < len(datasetSizes) {
if epoch < maxEpoch {
return datasetSizes[epoch]
}
// We don't have a way to verify primes fast before Go 1.8

11
consensus/ethash/algorithm_go1.8.go
View file

@ -27,10 +27,14 @@ import "math/big"
func cacheSize(block uint64) uint64 {
// If we have a pre-generated value, use that
epoch := int(block / epochLength)
if epoch < len(cacheSizes) {
if epoch < maxEpoch {
return cacheSizes[epoch]
}
// No known cache size, calculate manually (sanity branch only)
return calcCacheSize(epoch)
}
func calcCacheSize(epoch int) uint64 {
size := cacheInitBytes + cacheGrowthBytes*uint64(epoch) - hashBytes
for !new(big.Int).SetUint64(size / hashBytes).ProbablyPrime(1) { // Always accurate for n < 2^64
size -= 2 * hashBytes
@ -48,7 +52,10 @@ func datasetSize(block uint64) uint64 {
if epoch < len(datasetSizes) {
return datasetSizes[epoch]
}
// No known dataset size, calculate manually (sanity branch only)
return calcDatasetSize(epoch)
}
func calcDatasetSize(epoch int) uint64 {
size := datasetInitBytes + datasetGrowthBytes*uint64(epoch) - mixBytes
for !new(big.Int).SetUint64(size / mixBytes).ProbablyPrime(1) { // Always accurate for n < 2^64
size -= 2 * mixBytes

23
consensus/ethash/algorithm_go1.8_test.go
View file

@ -23,24 +23,15 @@ import "testing"
// Tests whether the dataset size calculator works correctly by cross checking the
// hard coded lookup table with the value generated by it.
func TestSizeCalculations(t *testing.T) {
var tests []uint64
// Verify all the cache sizes from the lookup table
defer func(sizes []uint64) { cacheSizes = sizes }(cacheSizes)
tests, cacheSizes = cacheSizes, []uint64{}
for i, test := range tests {
if size := cacheSize(uint64(i*epochLength) + 1); size != test {
t.Errorf("cache %d: cache size mismatch: have %d, want %d", i, size, test)
// Verify all the cache and dataset sizes from the lookup table.
for epoch, want := range cacheSizes {
if size := calcCacheSize(epoch); size != want {
t.Errorf("cache %d: cache size mismatch: have %d, want %d", epoch, size, want)
}
}
// Verify all the dataset sizes from the lookup table
defer func(sizes []uint64) { datasetSizes = sizes }(datasetSizes)
tests, datasetSizes = datasetSizes, []uint64{}
for i, test := range tests {
if size := datasetSize(uint64(i*epochLength) + 1); size != test {
t.Errorf("dataset %d: dataset size mismatch: have %d, want %d", i, size, test)
for epoch, want := range datasetSizes {
if size := calcDatasetSize(epoch); size != want {
t.Errorf("dataset %d: dataset size mismatch: have %d, want %d", epoch, size, want)
}
}
}

2
consensus/ethash/consensus.go
View file

@ -476,7 +476,7 @@ func (ethash *Ethash) VerifySeal(chain consensus.ChainReader, header *types.Head
}
// Sanity check that the block number is below the lookup table size (60M blocks)
number := header.Number.Uint64()
if number/epochLength >= uint64(len(cacheSizes)) {
if number/epochLength >= maxEpoch {
// Go < 1.7 cannot calculate new cache/dataset sizes (no fast prime check)
return errNonceOutOfRange
}