Governable block gas limit (#522)

build/ci.go

@@ -282,6 +282,9 @@ func buildFlags(env build.Environment) (flags []string) {
 	}
 	if runtime.GOOS == "darwin" {
 		ld = append(ld, "-s")
+	} else {
+		ld = append(ld, "-extldflags")
+		ld = append(ld, "-pthread")
 	}
 
 	if len(ld) > 0 {

cmd/puppeth/genesis.go

@@ -44,10 +44,8 @@ type alethGenesisSpec struct {
 		EIP158ForkBlock         hexutil.Uint64         `json:"EIP158ForkBlock"`
 		ByzantiumForkBlock      hexutil.Uint64         `json:"byzantiumForkBlock"`
 		ConstantinopleForkBlock hexutil.Uint64         `json:"constantinopleForkBlock"`
-		MinGasLimit             hexutil.Uint64         `json:"minGasLimit"`
 		MaxGasLimit             hexutil.Uint64         `json:"maxGasLimit"`
 		TieBreakingGas          bool                   `json:"tieBreakingGas"`
-		GasLimitBoundDivisor    math2.HexOrDecimal64   `json:"gasLimitBoundDivisor"`
 		MinimumDifficulty       *hexutil.Big           `json:"minimumDifficulty"`
 		DifficultyBoundDivisor  *math2.HexOrDecimal256 `json:"difficultyBoundDivisor"`
 		DurationLimit           *math2.HexOrDecimal256 `json:"durationLimit"`
@@ -124,11 +122,9 @@ func newAlethGenesisSpec(network string, genesis *core.Genesis) (*alethGenesisSp
 	spec.Params.NetworkID = (hexutil.Uint64)(genesis.Config.ChainID.Uint64())
 	spec.Params.ChainID = (hexutil.Uint64)(genesis.Config.ChainID.Uint64())
 	spec.Params.MaximumExtraDataSize = (hexutil.Uint64)(params.MaximumExtraDataSize)
-	spec.Params.MinGasLimit = (hexutil.Uint64)(params.MinGasLimit)
 	spec.Params.MaxGasLimit = (hexutil.Uint64)(math.MaxInt64)
 	spec.Params.MinimumDifficulty = (*hexutil.Big)(params.MinimumDifficulty)
 	spec.Params.DifficultyBoundDivisor = (*math2.HexOrDecimal256)(params.DifficultyBoundDivisor)
-	spec.Params.GasLimitBoundDivisor = (math2.HexOrDecimal64)(params.GasLimitBoundDivisor)
 	spec.Params.DurationLimit = (*math2.HexOrDecimal256)(params.DurationLimit)
 	spec.Params.BlockReward = (*hexutil.Big)(ethash.FrontierBlockReward)
 
@@ -223,29 +219,27 @@ type parityChainSpec struct {
 	} `json:"engine"`
 
 	Params struct {
-		AccountStartNonce        hexutil.Uint64       `json:"accountStartNonce"`
-		MaximumExtraDataSize     hexutil.Uint64       `json:"maximumExtraDataSize"`
-		MinGasLimit              hexutil.Uint64       `json:"minGasLimit"`
-		GasLimitBoundDivisor     math2.HexOrDecimal64 `json:"gasLimitBoundDivisor"`
-		NetworkID                hexutil.Uint64       `json:"networkID"`
-		ChainID                  hexutil.Uint64       `json:"chainID"`
-		MaxCodeSize              hexutil.Uint64       `json:"maxCodeSize"`
-		MaxCodeSizeTransition    hexutil.Uint64       `json:"maxCodeSizeTransition"`
-		EIP98Transition          hexutil.Uint64       `json:"eip98Transition"`
-		EIP150Transition         hexutil.Uint64       `json:"eip150Transition"`
-		EIP160Transition         hexutil.Uint64       `json:"eip160Transition"`
-		EIP161abcTransition      hexutil.Uint64       `json:"eip161abcTransition"`
-		EIP161dTransition        hexutil.Uint64       `json:"eip161dTransition"`
-		EIP155Transition         hexutil.Uint64       `json:"eip155Transition"`
-		EIP140Transition         hexutil.Uint64       `json:"eip140Transition"`
-		EIP211Transition         hexutil.Uint64       `json:"eip211Transition"`
-		EIP214Transition         hexutil.Uint64       `json:"eip214Transition"`
-		EIP658Transition         hexutil.Uint64       `json:"eip658Transition"`
-		EIP145Transition         hexutil.Uint64       `json:"eip145Transition"`
-		EIP1014Transition        hexutil.Uint64       `json:"eip1014Transition"`
-		EIP1052Transition        hexutil.Uint64       `json:"eip1052Transition"`
-		EIP1283Transition        hexutil.Uint64       `json:"eip1283Transition"`
-		EIP1283DisableTransition hexutil.Uint64       `json:"eip1283DisableTransition"`
+		AccountStartNonce        hexutil.Uint64 `json:"accountStartNonce"`
+		MaximumExtraDataSize     hexutil.Uint64 `json:"maximumExtraDataSize"`
+		NetworkID                hexutil.Uint64 `json:"networkID"`
+		ChainID                  hexutil.Uint64 `json:"chainID"`
+		MaxCodeSize              hexutil.Uint64 `json:"maxCodeSize"`
+		MaxCodeSizeTransition    hexutil.Uint64 `json:"maxCodeSizeTransition"`
+		EIP98Transition          hexutil.Uint64 `json:"eip98Transition"`
+		EIP150Transition         hexutil.Uint64 `json:"eip150Transition"`
+		EIP160Transition         hexutil.Uint64 `json:"eip160Transition"`
+		EIP161abcTransition      hexutil.Uint64 `json:"eip161abcTransition"`
+		EIP161dTransition        hexutil.Uint64 `json:"eip161dTransition"`
+		EIP155Transition         hexutil.Uint64 `json:"eip155Transition"`
+		EIP140Transition         hexutil.Uint64 `json:"eip140Transition"`
+		EIP211Transition         hexutil.Uint64 `json:"eip211Transition"`
+		EIP214Transition         hexutil.Uint64 `json:"eip214Transition"`
+		EIP658Transition         hexutil.Uint64 `json:"eip658Transition"`
+		EIP145Transition         hexutil.Uint64 `json:"eip145Transition"`
+		EIP1014Transition        hexutil.Uint64 `json:"eip1014Transition"`
+		EIP1052Transition        hexutil.Uint64 `json:"eip1052Transition"`
+		EIP1283Transition        hexutil.Uint64 `json:"eip1283Transition"`
+		EIP1283DisableTransition hexutil.Uint64 `json:"eip1283DisableTransition"`
 	} `json:"params"`
 
 	Genesis struct {
@@ -354,8 +348,6 @@ func newParityChainSpec(network string, genesis *core.Genesis, bootnodes []strin
 	}
 
 	spec.Params.MaximumExtraDataSize = (hexutil.Uint64)(params.MaximumExtraDataSize)
-	spec.Params.MinGasLimit = (hexutil.Uint64)(params.MinGasLimit)
-	spec.Params.GasLimitBoundDivisor = (math2.HexOrDecimal64)(params.GasLimitBoundDivisor)
 	spec.Params.NetworkID = (hexutil.Uint64)(genesis.Config.ChainID.Uint64())
 	spec.Params.ChainID = (hexutil.Uint64)(genesis.Config.ChainID.Uint64())
 	spec.Params.MaxCodeSize = params.MaxCodeSize

consensus/ethash/consensus.go

@@ -284,11 +284,7 @@ func (ethash *Ethash) verifyHeader(chain consensus.ChainReader, header, parent *
 	if diff < 0 {
 		diff *= -1
 	}
-	limit := parent.GasLimit / params.GasLimitBoundDivisor
 
-	if uint64(diff) >= limit || header.GasLimit < params.MinGasLimit {
-		return fmt.Errorf("invalid gas limit: have %d, want %d += %d", header.GasLimit, parent.GasLimit, limit)
-	}
 	// Verify that the block number is parent's +1
 	if diff := new(big.Int).Sub(header.Number, parent.Number); diff.Cmp(big.NewInt(1)) != 0 {
 		return consensus.ErrInvalidNumber

consensus/istanbul/backend/engine_test.go

@@ -214,7 +214,7 @@ func newBlockChain(n int, isFullChain bool) (*core.BlockChain, *Backend) {
 func createRandomDataDir() string {
 	rand.Seed(time.Now().UnixNano())
 	for {
-		dirName := "geth_ibft_" + strconv.Itoa(rand.Int()%1000)
+		dirName := "geth_ibft_" + strconv.Itoa(rand.Int()%1000000)
 		dataDir := filepath.Join("/tmp", dirName)
 		err := os.Mkdir(dataDir, 0700)
 		if os.IsExist(err) {
@@ -270,7 +270,7 @@ func makeHeader(parent *types.Block, config *istanbul.Config) *types.Header {
 	header := &types.Header{
 		ParentHash: parent.Hash(),
 		Number:     parent.Number().Add(parent.Number(), common.Big1),
-		GasLimit:   core.CalcGasLimit(parent, parent.GasLimit(), parent.GasLimit()),
+		GasLimit:   core.CalcGasLimit(parent, nil),
 		GasUsed:    0,
 		Extra:      parent.Extra(),
 		Time:       new(big.Int).Add(parent.Time(), new(big.Int).SetUint64(config.BlockPeriod)),

consensus/istanbul/core/testbackend_test.go

@@ -442,7 +442,7 @@ func (t *testSystem) NewBackend(id uint64) *testSystemBackend {
 func createRandomDataDir() string {
 	rand.Seed(time.Now().UnixNano())
 	for {
-		dirName := "geth_ibft_" + strconv.Itoa(rand.Int()%1000)
+		dirName := "geth_ibft_" + strconv.Itoa(rand.Int()%1000000)
 		dataDir := filepath.Join("/tmp", dirName)
 		err := os.Mkdir(dataDir, 0700)
 		if os.IsExist(err) {

contract_comm/blockchain_parameters/blockchain_parameters.go

@@ -53,6 +53,20 @@ const (
 			"type": "function"
 	},
 	{
+		"constant": true,
+		"inputs": [],
+		"name": "blockGasLimit",
+		"outputs": [
+		  {
+			"name": "",
+			"type": "uint256"
+		  }
+		],
+		"payable": false,
+		"stateMutability": "view",
+		"type": "function"
+	  },
+	  {
 		"constant": true,
 		"inputs": [],
 		"name": "intrinsicGasForAlternativeGasCurrency",
@@ -146,3 +160,21 @@ func SpawnCheck() {
 		}
 	}()
 }
+
+func GetBlockGasLimit(header *types.Header, state vm.StateDB) (uint64, error) {
+	var gasLimit *big.Int
+	_, err := contract_comm.MakeStaticCall(
+		params.BlockchainParametersRegistryId,
+		blockchainParametersABI,
+		"blockGasLimit",
+		[]interface{}{},
+		&gasLimit,
+		params.MaxGasForReadBlockchainParameter,
+		header,
+		state,
+	)
+	if err != nil {
+		return params.DefaultGasLimit, err
+	}
+	return gasLimit.Uint64(), nil
+}

core/bench_test.go

@@ -112,7 +112,7 @@ func genTxRing(naccounts int) func(int, *BlockGen) {
 	from := 0
 	return func(i int, gen *BlockGen) {
 		block := gen.PrevBlock(i - 1)
-		gas := CalcGasLimit(block, block.GasLimit(), block.GasLimit())
+		gas := CalcGasLimit(block, nil)
 		for {
 			gas -= params.TxGas
 			if gas < params.TxGas {

core/block_validator.go

@@ -20,8 +20,10 @@ import (
 	"fmt"
 
 	"github.com/ethereum/go-ethereum/consensus"
+	"github.com/ethereum/go-ethereum/contract_comm/blockchain_parameters"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/params"
 )
 
@@ -105,35 +107,16 @@ func (v *BlockValidator) ValidateState(block, parent *types.Block, statedb *stat
 // to keep the baseline gas above the provided floor, and increase it towards the
 // ceil if the blocks are full. If the ceil is exceeded, it will always decrease
 // the gas allowance.
-func CalcGasLimit(parent *types.Block, gasFloor, gasCeil uint64) uint64 {
-	// contrib = (parentGasUsed * 3 / 2) / 1024
-	contrib := (parent.GasUsed() + parent.GasUsed()/2) / params.GasLimitBoundDivisor
+func CalcGasLimit(parent *types.Block, statedb *state.StateDB) uint64 {
+	header := parent.Header()
 
-	// decay = parentGasLimit / 1024 -1
-	decay := parent.GasLimit()/params.GasLimitBoundDivisor - 1
+	limit, err := blockchain_parameters.GetBlockGasLimit(header, statedb)
 
-	/*
-		strategy: gasLimit of block-to-mine is set based on parent's
-		gasUsed value.  if parentGasUsed > parentGasLimit * (2/3) then we
-		increase it, otherwise lower it (or leave it unchanged if it's right
-		at that usage) the amount increased/decreased depends on how far away
-		from parentGasLimit * (2/3) parentGasUsed is.
-	*/
-	limit := parent.GasLimit() - decay + contrib
-	if limit < params.MinGasLimit {
-		limit = params.MinGasLimit
+	if err == nil {
+		return limit
 	}
-	// If we're outside our allowed gas range, we try to hone towards them
-	if limit < gasFloor {
-		limit = parent.GasLimit() + decay
-		if limit > gasFloor {
-			limit = gasFloor
-		}
-	} else if limit > gasCeil {
-		limit = parent.GasLimit() - decay
-		if limit < gasCeil {
-			limit = gasCeil
-		}
-	}
-	return limit
+
+	log.Warn("Cannot read block gas limit", "err", err)
+
+	return params.DefaultGasLimit
 }

core/chain_makers.go

@@ -242,7 +242,7 @@ func makeHeader(chain consensus.ChainReader, parent *types.Block, state *state.S
 			Difficulty: parent.Difficulty(),
 			UncleHash:  parent.UncleHash(),
 		}),
-		GasLimit: CalcGasLimit(parent, parent.GasLimit(), parent.GasLimit()),
+		GasLimit: CalcGasLimit(parent, state),
 		Number:   new(big.Int).Add(parent.Number(), common.Big1),
 		Time:     time,
 	}

core/genesis.go

@@ -258,7 +258,7 @@ func (g *Genesis) ToBlock(db ethdb.Database) *types.Block {
 		Root:       root,
 	}
 	if g.GasLimit == 0 {
-		head.GasLimit = params.GenesisGasLimit
+		head.GasLimit = params.DefaultGasLimit
 	}
 	if g.Difficulty == nil {
 		head.Difficulty = params.GenesisDifficulty

core/genesis_test.go

@@ -43,7 +43,7 @@ func TestDefaultGenesisBlock(t *testing.T) {
 
 func TestSetupGenesis(t *testing.T) {
 	var (
-		customghash = common.HexToHash("0x89c99d90b79719238d2645c7642f2c9295246e80775b38cfd162b696817fbd50")
+		customghash = common.HexToHash("0x603e4119abc46d60fb1d5116bd810c207e6639053517f0632c9cebad854ee0c0")
 		customg     = Genesis{
 			Config: &params.ChainConfig{HomesteadBlock: big.NewInt(3)},
 			Alloc: GenesisAlloc{

eth/fetcher/fetcher_test.go

@@ -38,7 +38,7 @@ var (
 	testKey, _   = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
 	testAddress  = crypto.PubkeyToAddress(testKey.PublicKey)
 	genesis      = core.GenesisBlockForTesting(testdb, testAddress, big.NewInt(1000000000))
-	unknownBlock = types.NewBlock(&types.Header{GasLimit: params.GenesisGasLimit}, nil, nil, nil, nil)
+	unknownBlock = types.NewBlock(&types.Header{GasLimit: params.DefaultGasLimit}, nil, nil, nil, nil)
 )
 
 // makeChain creates a chain of n blocks starting at and including parent.

miner/worker.go

@@ -909,10 +909,16 @@ func (w *worker) commitNewWork(interrupt *int32, noempty bool, timestamp int64)
 	}
 
 	num := parent.Number()
+	limit := uint64(0)
+	if w.current != nil {
+		limit = core.CalcGasLimit(parent, w.current.state)
+	} else {
+		limit = core.CalcGasLimit(parent, nil)
+	}
 	header := &types.Header{
 		ParentHash: parent.Hash(),
 		Number:     num.Add(num, common.Big1),
-		GasLimit:   core.CalcGasLimit(parent, w.gasFloor, w.gasCeil),
+		GasLimit:   limit,
 		Extra:      w.extra,
 		Time:       big.NewInt(timestamp),
 	}

miner/worker_test.go

@@ -178,7 +178,7 @@ func newTestWorker(t *testing.T, chainConfig *params.ChainConfig, engine consens
 	if shouldAddPendingTxs {
 		backend.txPool.AddLocals(pendingTxs)
 	}
-	w := newWorker(chainConfig, engine, backend, new(event.TypeMux), time.Second, params.GenesisGasLimit, params.GenesisGasLimit, nil, testVerificationService, &backend.db)
+	w := newWorker(chainConfig, engine, backend, new(event.TypeMux), time.Second, params.DefaultGasLimit, params.DefaultGasLimit, nil, testVerificationService, &backend.db)
 	w.setEtherbase(testBankAddress)
 	return w, backend
 }

params/protocol_params.go

@@ -24,9 +24,7 @@ import (
 )
 
 const (
-	GasLimitBoundDivisor uint64 = 1024    // The bound divisor of the gas limit, used in update calculations.
-	MinGasLimit          uint64 = 5000    // Minimum the gas limit may ever be.
-	GenesisGasLimit      uint64 = 4712388 // Gas limit of the Genesis block.
+	DefaultGasLimit uint64 = 20000000 // Gas limit of the blocks before BlockchainParams contract is loaded.
 
 	MaximumExtraDataSize  uint64 = 32    // Maximum size extra data may be after Genesis.
 	ExpByteGas            uint64 = 10    // Times ceil(log256(exponent)) for the EXP instruction.