fees: update fee scalar

Author: tynes

l2geth/core/types/transaction.go

@@ -27,6 +27,7 @@ import (
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/rlp"
+	"github.com/ethereum/go-ethereum/rollup/fees"
 )
 
 //go:generate gencodec -type txdata -field-override txdataMarshaling -out gen_tx_json.go
@@ -225,7 +226,7 @@ func (tx *Transaction) UnmarshalJSON(input []byte) error {
 
 func (tx *Transaction) Data() []byte       { return common.CopyBytes(tx.data.Payload) }
 func (tx *Transaction) Gas() uint64        { return tx.data.GasLimit }
-func (tx *Transaction) L2Gas() uint64      { return tx.data.GasLimit % 100_000_000 }
+func (tx *Transaction) L2Gas() uint64      { return fees.DecodeL2GasLimitU64(tx.data.GasLimit) }
 func (tx *Transaction) GasPrice() *big.Int { return new(big.Int).Set(tx.data.Price) }
 func (tx *Transaction) Value() *big.Int    { return new(big.Int).Set(tx.data.Amount) }
 func (tx *Transaction) Nonce() uint64      { return tx.data.AccountNonce }

l2geth/rollup/fees/rollup_fee.go

@@ -11,12 +11,9 @@ import (
 // transaction in gas.
 const overhead uint64 = 4200 + 200*params.TxDataNonZeroGasEIP2028
 
-// hundredMillion is a constant used in the gas encoding formula
-const hundredMillion uint64 = 100_000_000
-
 // feeScalar is used to scale the calculations in EncodeL2GasLimit
 // to prevent them from being too large
-const feeScalar uint64 = 1000
+const feeScalar uint64 = 10_000_000
 
 // TxGasPrice is a constant that determines the result of `eth_gasPrice`
 // It is scaled upwards by 50%
@@ -27,8 +24,10 @@ const TxGasPrice uint64 = feeScalar + (feeScalar / 2)
 // BigTxGasPrice is the L2GasPrice as type big.Int
 var BigTxGasPrice = new(big.Int).SetUint64(TxGasPrice)
 var bigFeeScalar = new(big.Int).SetUint64(feeScalar)
-var bigHundredMillion = new(big.Int).SetUint64(hundredMillion)
-var BigTenThousand = new(big.Int).SetUint64(10000)
+
+const tenThousand = 10000
+
+var BigTenThousand = new(big.Int).SetUint64(tenThousand)
 
 // EncodeTxGasLimit computes the `tx.gasLimit` based on the L1/L2 gas prices and
 // the L2 gas limit. The L2 gas limit is encoded inside of the lower order bits
@@ -42,12 +41,14 @@ var BigTenThousand = new(big.Int).SetUint64(10000)
 // the fee, so increasing the L2 Gas limit will increase the fee paid.
 // The calculation is:
 // l1GasLimit = zero_count(data) * 4 + non_zero_count(data) * 16 + overhead
+// roundedL2GasLimit = ceilmod(l2GasLimit, 10_000)
 // l1Fee = l1GasPrice * l1GasLimit
-// l2Fee = l2GasPrice * l2GasLimit
+// l2Fee = l2GasPrice * roundedL2GasLimit
 // sum = l1Fee + l2Fee
 // scaled = sum / scalar
-// rounded = ceilmod(scaled, hundredMillion)
-// result = rounded + l2GasLimit
+// rounded = ceilmod(scaled, tenThousand)
+// roundedScaledL2GasLimit = roundedL2GasLimit / tenThousand
+// result = rounded + roundedScaledL2GasLimit
 // Note that for simplicity purposes, only the calldata is passed into this
 // function when in reality the RLP encoded transaction should be. The
 // additional cost is added to the overhead constant to prevent the need to RLP
@@ -59,7 +60,7 @@ func EncodeTxGasLimit(data []byte, l1GasPrice, l2GasLimit, l2GasPrice *big.Int)
 	l2Fee := new(big.Int).Mul(l2GasPrice, roundedL2GasLimit)
 	sum := new(big.Int).Add(l1Fee, l2Fee)
 	scaled := new(big.Int).Div(sum, bigFeeScalar)
-	rounded := Ceilmod(scaled, bigHundredMillion)
+	rounded := Ceilmod(scaled, BigTenThousand)
 	roundedScaledL2GasLimit := new(big.Int).Div(roundedL2GasLimit, BigTenThousand)
 	result := new(big.Int).Add(rounded, roundedScaledL2GasLimit)
 	return result
@@ -81,6 +82,11 @@ func DecodeL2GasLimit(gasLimit *big.Int) *big.Int {
 	return new(big.Int).Mul(scaled, BigTenThousand)
 }
 
+func DecodeL2GasLimitU64(gasLimit uint64) uint64 {
+	scaled := gasLimit % tenThousand
+	return scaled * tenThousand
+}
+
 // calculateL1GasLimit computes the L1 gasLimit based on the calldata and
 // constant sized overhead. The overhead can be decreased as the cost of the
 // batch submission goes down via contract optimizations. This will not overflow

packages/core-utils/src/fees.ts

@@ -6,7 +6,7 @@ import { BigNumber } from 'ethers'
 import { remove0x } from './common'
 
 const hundredMillion = BigNumber.from(100_000_000)
-const feeScalar = 1000
+const feeScalar = 10_000_000
 export const TxGasPrice = BigNumber.from(feeScalar + feeScalar / 2)
 const txDataZeroGas = 4
 const txDataNonZeroGasEIP2028 = 16
@@ -38,7 +38,7 @@ function encode(input: EncodableL2GasLimit): BigNumber {
   const l2Fee = roundedL2GasLimit.mul(l2GasPrice)
   const sum = l1Fee.add(l2Fee)
   const scaled = sum.div(feeScalar)
-  const rounded = ceilmod(scaled, hundredMillion)
+  const rounded = ceilmod(scaled, tenThousand)
   const roundedScaledL2GasLimit = roundedL2GasLimit.div(tenThousand)
   return rounded.add(roundedScaledL2GasLimit)
 }