GasLimit adjustment steps for the Testnet

GasLimit  ceiling target changes based on 4 steps
Each step is 150,000 blocks (i.e expected blocks for 3 weeks)

GasCeil is changed to 110M because it is enough to accomodate the 1700 testnet
target

These changes are for the testnet and probably is not a long term
controller

cmd/utils/flags.go

@@ -1240,43 +1240,57 @@ func setTxPool(ctx *cli.Context, cfg *core.TxPoolConfig) {
 	}
 }
 
-func setDurationLimit(ctx *cli.Context, cfg *ethconfig.Config) {
+func setConsensusEngineConfig(ctx *cli.Context, cfg *ethconfig.Config) {
 	if cfg.ConsensusEngine == "blake3" {
 		// Override any default configs for hard coded networks.
 		switch {
 		case ctx.GlobalBool(ColosseumFlag.Name):
 			cfg.Blake3Pow.DurationLimit = params.DurationLimit
+			cfg.Blake3Pow.GasCeil = params.ColosseumGasCeil
 		case ctx.GlobalBool(GardenFlag.Name):
 			cfg.Blake3Pow.DurationLimit = params.GardenDurationLimit
+			cfg.Blake3Pow.GasCeil = params.GardenGasCeil
 		case ctx.GlobalBool(OrchardFlag.Name):
 			cfg.Blake3Pow.DurationLimit = params.OrchardDurationLimit
+			cfg.Blake3Pow.GasCeil = params.OrchardGasCeil
 		case ctx.GlobalBool(LighthouseFlag.Name):
 			cfg.Blake3Pow.DurationLimit = params.LighthouseDurationLimit
+			cfg.Blake3Pow.GasCeil = params.LighthouseGasCeil
 		case ctx.GlobalBool(LocalFlag.Name):
 			cfg.Blake3Pow.DurationLimit = params.LocalDurationLimit
+			cfg.Blake3Pow.GasCeil = params.LocalGasCeil
 		case ctx.GlobalBool(DeveloperFlag.Name):
 			cfg.Blake3Pow.DurationLimit = params.DurationLimit
+			cfg.Blake3Pow.GasCeil = params.LocalGasCeil
 		default:
 			cfg.Blake3Pow.DurationLimit = params.DurationLimit
+			cfg.Blake3Pow.GasCeil = params.GasCeil
 
 		}
 	} else {
 		// Override any default configs for hard coded networks.
 		switch {
 		case ctx.GlobalBool(ColosseumFlag.Name):
 			cfg.Progpow.DurationLimit = params.DurationLimit
+			cfg.Progpow.GasCeil = params.ColosseumGasCeil
 		case ctx.GlobalBool(GardenFlag.Name):
 			cfg.Progpow.DurationLimit = params.GardenDurationLimit
+			cfg.Progpow.GasCeil = params.GardenGasCeil
 		case ctx.GlobalBool(OrchardFlag.Name):
 			cfg.Progpow.DurationLimit = params.OrchardDurationLimit
+			cfg.Progpow.GasCeil = params.OrchardGasCeil
 		case ctx.GlobalBool(LighthouseFlag.Name):
 			cfg.Progpow.DurationLimit = params.LighthouseDurationLimit
+			cfg.Progpow.GasCeil = params.LighthouseGasCeil
 		case ctx.GlobalBool(LocalFlag.Name):
 			cfg.Progpow.DurationLimit = params.LocalDurationLimit
+			cfg.Progpow.GasCeil = params.LocalGasCeil
 		case ctx.GlobalBool(DeveloperFlag.Name):
 			cfg.Progpow.DurationLimit = params.DurationLimit
+			cfg.Progpow.GasCeil = params.LocalGasCeil
 		default:
 			cfg.Progpow.DurationLimit = params.DurationLimit
+			cfg.Progpow.GasCeil = params.GasCeil
 
 		}
 	}
@@ -1425,7 +1439,7 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *ethconfig.Config) {
 	} else {
 		cfg.ConsensusEngine = "progpow"
 	}
-	setDurationLimit(ctx, cfg)
+	setConsensusEngineConfig(ctx, cfg)
 
 	setWhitelist(ctx, cfg)
 

consensus/blake3pow/blake3pow.go

@@ -43,6 +43,8 @@ type Config struct {
 
 	DurationLimit *big.Int
 
+	GasCeil uint64
+
 	// When set, notifications sent by the remote sealer will
 	// be block header JSON objects instead of work package arrays.
 	NotifyFull bool

consensus/blake3pow/consensus.go

@@ -301,8 +301,10 @@ func (blake3pow *Blake3pow) verifyHeader(chain consensus.ChainHeaderReader, head
 		}
 		// Verify the block's gas usage and verify the base fee.
 		// Verify that the gas limit remains within allowed bounds
-		if err := misc.VerifyGaslimit(parent.GasLimit(), header.GasLimit()); err != nil {
-			return err
+		expectedGasLimit := core.CalcGasLimit(parent, blake3pow.config.GasCeil)
+		if expectedGasLimit != header.GasLimit() {
+			return fmt.Errorf("invalid gasLimit: have %d, want %d",
+				expectedGasLimit, header.GasLimit())
 		}
 		// Verify the header is not malformed
 		if header.BaseFee() == nil {

consensus/progpow/consensus.go

@@ -300,8 +300,10 @@ func (progpow *Progpow) verifyHeader(chain consensus.ChainHeaderReader, header,
 		}
 		// Verify the block's gas usage and verify the base fee.
 		// Verify that the gas limit remains within allowed bounds
-		if err := misc.VerifyGaslimit(parent.GasLimit(), header.GasLimit()); err != nil {
-			return err
+		expectedGasLimit := core.CalcGasLimit(parent, progpow.config.GasCeil)
+		if expectedGasLimit != header.GasLimit() {
+			return fmt.Errorf("invalid gasLimit: have %d, want %d",
+				expectedGasLimit, header.GasLimit())
 		}
 		// Verify the header is not malformed
 		if header.BaseFee() == nil {

consensus/progpow/progpow.go

@@ -157,6 +157,7 @@ type Config struct {
 	CachesOnDisk   int
 	CachesLockMmap bool
 	DurationLimit  *big.Int
+	GasCeil        uint64
 
 	// When set, notifications sent by the remote sealer will
 	// be block header JSON objects instead of work package arrays.

core/block_validator.go

@@ -144,25 +144,42 @@ func (v *BlockValidator) ValidateState(block *types.Block, statedb *state.StateD
 // CalcGasLimit computes the gas limit of the next block after parent. It aims
 // to keep the baseline gas close to the provided target, and increase it towards
 // the target if the baseline gas is lower.
-func CalcGasLimit(parentGasLimit, desiredLimit uint64) uint64 {
+func CalcGasLimit(parent *types.Header, gasCeil uint64) uint64 {
+
+	parentGasLimit := parent.GasLimit()
+
 	delta := parentGasLimit/params.GasLimitBoundDivisor - 1
 	limit := parentGasLimit
-	if desiredLimit < params.MinGasLimit {
+
+	var desiredLimit uint64
+	percentGasUsed := parent.GasUsed() * 100 / parent.GasLimit()
+	if percentGasUsed > params.PercentGasUsedThreshold {
+		desiredLimit = CalcGasCeil(parent.NumberU64(), gasCeil)
+		if desiredLimit > gasCeil {
+			desiredLimit = gasCeil
+		}
+		if limit+delta > desiredLimit {
+			return desiredLimit
+		} else {
+			return limit + delta
+		}
+	} else {
 		desiredLimit = params.MinGasLimit
-	}
-	// If we're outside our allowed gas range, we try to hone towards them
-	if limit < desiredLimit {
-		limit = parentGasLimit + delta
-		if limit > desiredLimit {
-			limit = desiredLimit
+		if limit-delta/2 < desiredLimit {
+			return desiredLimit
+		} else {
+			return limit - delta/2
 		}
-		return limit
 	}
-	if limit > desiredLimit {
-		limit = parentGasLimit - delta
-		if limit < desiredLimit {
-			limit = desiredLimit
-		}
+}
+
+func CalcGasCeil(blockNumber uint64, gasCeil uint64) uint64 {
+	if blockNumber < params.GasLimitStepOneBlockThreshold {
+		return gasCeil / 4
+	} else if blockNumber < params.GasLimitStepTwoBlockThreshold {
+		return gasCeil / 2
+	} else if blockNumber < params.GasLimitStepThreeBlockThreshold {
+		return gasCeil * 3 / 4
 	}
-	return limit
+	return gasCeil
 }

core/slice.go

@@ -323,7 +323,7 @@ func (sl *Slice) Append(header *types.Header, domPendingHeader *types.Header, do
 	log.Info("times during sub append:", "t6_1:", time6_1, "t6_2:", time6_2, "t6_3:", time6_3)
 	log.Info("Appended new block", "number", block.Header().Number(), "hash", block.Hash(),
 		"difficulty", block.Header().Difficulty(),
-		"uncles", len(block.Uncles()), "txs", len(block.Transactions()), "etxs", len(block.ExtTransactions()), "gas", block.GasUsed(),
+		"uncles", len(block.Uncles()), "txs", len(block.Transactions()), "etxs", len(block.ExtTransactions()), "gas", block.GasUsed(), "gasLimit", block.GasLimit(),
 		"root", block.Root(),
 		"order", order,
 		"location", block.Header().Location(),

core/worker.go

@@ -881,12 +881,7 @@ func (w *worker) fillTransactions(interrupt *int32, env *environment, block *typ
 // into the given sealing block. The transaction selection and ordering strategy can
 // be customized with the plugin in the future.
 func (w *worker) adjustGasLimit(interrupt *int32, env *environment, parent *types.Block) {
-	percentGasUsed := parent.GasUsed() * 100 / parent.GasLimit()
-	if percentGasUsed > params.PercentGasUsedThreshold {
-		env.header.SetGasLimit(CalcGasLimit(parent.GasLimit(), w.config.GasCeil))
-	} else {
-		env.header.SetGasLimit(CalcGasLimit(parent.GasLimit(), w.config.GasFloor))
-	}
+	env.header.SetGasLimit(CalcGasLimit(parent.Header(), w.config.GasCeil))
 }
 
 // ComputeManifestHash given a header computes the manifest hash for the header

eth/ethconfig/config.go

@@ -181,6 +181,7 @@ func CreateProgpowConsensusEngine(stack *node.Node, chainConfig *params.ChainCon
 		PowMode:       config.PowMode,
 		NotifyFull:    config.NotifyFull,
 		DurationLimit: config.DurationLimit,
+		GasCeil:       config.GasCeil,
 	}, notify, noverify)
 	engine.SetThreads(-1) // Disable CPU mining
 	return engine
@@ -201,6 +202,7 @@ func CreateBlake3ConsensusEngine(stack *node.Node, chainConfig *params.ChainConf
 		PowMode:       config.PowMode,
 		NotifyFull:    config.NotifyFull,
 		DurationLimit: config.DurationLimit,
+		GasCeil:       config.GasCeil,
 	}, notify, noverify)
 	engine.SetThreads(-1) // Disable CPU mining
 	return engine

params/protocol_params.go

@@ -23,10 +23,13 @@ import (
 )
 
 const (
-	GasLimitBoundDivisor    uint64 = 1024    // The bound divisor of the gas limit, used in update calculations.
-	PercentGasUsedThreshold uint64 = 95      // Percent Gas used threshold at which the gas limit adjusts
-	MinGasLimit             uint64 = 5000000 // Minimum the gas limit may ever be.
-	GenesisGasLimit         uint64 = 5000000 // Gas limit of the Genesis block.
+	GasLimitBoundDivisor            uint64 = 1024 // The bound divisor of the gas limit, used in update calculations.
+	PercentGasUsedThreshold         uint64 = 50   // Percent Gas used threshold at which the gas limit adjusts
+	GasLimitStepOneBlockThreshold   uint64 = 150000
+	GasLimitStepTwoBlockThreshold   uint64 = 300000
+	GasLimitStepThreeBlockThreshold uint64 = 450000
+	MinGasLimit                     uint64 = 5000000 // Minimum the gas limit may ever be.
+	GenesisGasLimit                 uint64 = 5000000 // Gas limit of the Genesis block.
 
 	MaximumExtraDataSize  uint64 = 32                                                       // Maximum size extra data may be after Genesis.
 	ExpByteGas            uint64 = 10                                                       // Times ceil(log256(exponent)) for the EXP instruction.
@@ -138,7 +141,8 @@ const (
 )
 
 var (
-	ColosseumGasCeil           uint64 = 160000000
+	GasCeil                    uint64 = 20000000
+	ColosseumGasCeil           uint64 = 110000000
 	GardenGasCeil              uint64 = 160000000
 	OrchardGasCeil             uint64 = 50000000
 	LighthouseGasCeil          uint64 = 160000000