Use transaction-payment's congestion modifier for Ethereum base-fee

node/service/Cargo.toml

@@ -50,6 +50,7 @@ moonriver-runtime = { path = "../../runtime/moonriver", optional = true }
 
 # Substrate
 frame-system-rpc-runtime-api = { git = "https://github.com/purestake/substrate", branch = "moonbeam-polkadot-v0.9.32" }
+pallet-transaction-payment = { git = "https://github.com/purestake/substrate", branch = "moonbeam-polkadot-v0.9.32" }
 pallet-transaction-payment-rpc = { git = "https://github.com/purestake/substrate", branch = "moonbeam-polkadot-v0.9.32" }
 pallet-transaction-payment-rpc-runtime-api = { git = "https://github.com/purestake/substrate", branch = "moonbeam-polkadot-v0.9.32" }
 parity-scale-codec = "3.0.0"

node/service/src/chain_spec/moonbase.rs

@@ -30,9 +30,10 @@ use moonbase_runtime::{
 	EthereumChainIdConfig, EthereumConfig, GenesisAccount, GenesisConfig, InflationInfo,
 	MaintenanceModeConfig, ParachainInfoConfig, ParachainStakingConfig, PolkadotXcmConfig,
 	Precompiles, Range, SudoConfig, SystemConfig, TechCommitteeCollectiveConfig,
-	TreasuryCouncilCollectiveConfig, HOURS, WASM_BINARY,
+	TransactionPaymentConfig, TreasuryCouncilCollectiveConfig, HOURS, WASM_BINARY,
 };
 use nimbus_primitives::NimbusId;
+use pallet_transaction_payment::Multiplier;
 use sc_service::ChainType;
 #[cfg(test)]
 use sp_core::ecdsa;
@@ -321,6 +322,9 @@ pub fn testnet_genesis(
 		},
 		// This should initialize it to whatever we have set in the pallet
 		polkadot_xcm: PolkadotXcmConfig::default(),
+		transaction_payment: TransactionPaymentConfig {
+			multiplier: Multiplier::from(8u128),
+		},
 	}
 }
 

node/service/src/chain_spec/moonbeam.rs

@@ -30,10 +30,11 @@ use moonbeam_runtime::{
 	Balance, BalancesConfig, CouncilCollectiveConfig, CrowdloanRewardsConfig, DemocracyConfig,
 	EVMConfig, EthereumChainIdConfig, EthereumConfig, GenesisAccount, GenesisConfig, InflationInfo,
 	MaintenanceModeConfig, ParachainInfoConfig, ParachainStakingConfig, PolkadotXcmConfig,
-	Precompiles, Range, SystemConfig, TechCommitteeCollectiveConfig,
+	Precompiles, Range, SystemConfig, TechCommitteeCollectiveConfig, TransactionPaymentConfig,
 	TreasuryCouncilCollectiveConfig, HOURS, WASM_BINARY,
 };
 use nimbus_primitives::NimbusId;
+use pallet_transaction_payment::Multiplier;
 use sc_service::ChainType;
 #[cfg(test)]
 use sp_core::ecdsa;
@@ -313,6 +314,9 @@ pub fn testnet_genesis(
 		},
 		// This should initialize it to whatever we have set in the pallet
 		polkadot_xcm: PolkadotXcmConfig::default(),
+		transaction_payment: TransactionPaymentConfig {
+			multiplier: Multiplier::from(8u128),
+		},
 	}
 }
 

node/service/src/chain_spec/moonriver.rs

@@ -30,10 +30,11 @@ use moonriver_runtime::{
 	CouncilCollectiveConfig, CrowdloanRewardsConfig, DemocracyConfig, EVMConfig,
 	EthereumChainIdConfig, EthereumConfig, GenesisAccount, GenesisConfig, InflationInfo,
 	MaintenanceModeConfig, ParachainInfoConfig, ParachainStakingConfig, PolkadotXcmConfig,
-	Precompiles, Range, SystemConfig, TechCommitteeCollectiveConfig,
+	Precompiles, Range, SystemConfig, TechCommitteeCollectiveConfig, TransactionPaymentConfig,
 	TreasuryCouncilCollectiveConfig, HOURS, WASM_BINARY,
 };
 use nimbus_primitives::NimbusId;
+use pallet_transaction_payment::Multiplier;
 use sc_service::ChainType;
 #[cfg(test)]
 use sp_core::ecdsa;
@@ -313,6 +314,9 @@ pub fn testnet_genesis(
 		},
 		// This should initialize it to whatever we have set in the pallet
 		polkadot_xcm: PolkadotXcmConfig::default(),
+		transaction_payment: TransactionPaymentConfig {
+			multiplier: Multiplier::from(8u128),
+		},
 	}
 }
 

runtime/moonbase/src/lib.rs

@@ -196,7 +196,7 @@ pub fn native_version() -> NativeVersion {
 }
 
 const NORMAL_DISPATCH_RATIO: Perbill = Perbill::from_percent(75);
-const NORMAL_WEIGHT: Weight = MAXIMUM_BLOCK_WEIGHT.saturating_mul(3).saturating_div(4);
+pub const NORMAL_WEIGHT: Weight = MAXIMUM_BLOCK_WEIGHT.saturating_mul(3).saturating_div(4);
 // Here we assume Ethereum's base fee of 21000 gas and convert to weight, but we
 // subtract roughly the cost of a balance transfer from it (about 1/3 the cost)
 // and some cost to account for per-byte-fee.
@@ -388,27 +388,37 @@ parameter_types! {
 	pub const TargetBlockFullness: Perquintill = Perquintill::from_percent(25);
 	/// The adjustment variable of the runtime. Higher values will cause `TargetBlockFullness` to
 	/// change the fees more rapidly. This low value causes changes to occur slowly over time.
-	pub AdjustmentVariable: Multiplier = Multiplier::saturating_from_rational(3, 100_000);
+	pub AdjustmentVariable: Multiplier = Multiplier::saturating_from_rational(4, 1_000);
 	/// Minimum amount of the multiplier. This value cannot be too low. A test case should ensure
 	/// that combined with `AdjustmentVariable`, we can recover from the minimum.
 	/// See `multiplier_can_grow_from_zero` in integration_tests.rs.
-	/// This value is currently only used by pallet-transaction-payment as an assertion that the
-	/// next multiplier is always > min value.
-	pub MinimumMultiplier: Multiplier = Multiplier::saturating_from_rational(1, 1_000_000u128);
+	pub MinimumMultiplier: Multiplier = Multiplier::saturating_from_rational(1, 1_000);
 	/// Maximum multiplier. We pick a value that is expensive but not impossibly so; it should act
 	/// as a safety net.
 	pub MaximumMultiplier: Multiplier = Multiplier::from(100_000u128);
 	pub PrecompilesValue: MoonbasePrecompiles<Runtime> = MoonbasePrecompiles::<_>::new();
 	pub WeightPerGas: Weight = Weight::from_ref_time(WEIGHT_PER_GAS);
 }
 
-pub struct FixedGasPrice;
-impl FeeCalculator for FixedGasPrice {
+pub struct TransactionPaymentAsGasPrice;
+impl FeeCalculator for TransactionPaymentAsGasPrice {
 	fn min_gas_price() -> (U256, Weight) {
-		(
-			(1 * currency::GIGAWEI * currency::SUPPLY_FACTOR).into(),
-			Weight::zero(),
-		)
+		// TODO: transaction-payment differs from EIP-1559 in that its tip and length fees are not
+		//       scaled by the multiplier, which means its multiplier will be overstated when
+		//       applied to an ethereum transaction
+		// note: transaction-payment uses both a congestion modifier (next_fee_multiplier, which is
+		//       updated once per block in on_finalize) and a 'WeightToFee' implementation. Our
+		//       runtime implements this as a 'ConstantModifier', so we can get away with a simple
+		//       multiplication here.
+		// It is imperative that `saturating_mul_int` be performed as late as possible in the
+		// expression since it involves fixed point multiplication with a division by a fixed
+		// divisor. This leads to truncation and subsequent precision loss if performed too early.
+		// This can lead to min_gas_price being same across blocks even if the multiplier changes.
+		// There's still some precision loss when the final `gas_price` (used_gas * min_gas_price)
+		// is computed in frontier, but that's currently unavoidable.
+		let min_gas_price = TransactionPayment::next_fee_multiplier()
+			.saturating_mul_int(currency::WEIGHT_FEE.saturating_mul(WEIGHT_PER_GAS as u128));
+		(min_gas_price.into(), Weight::zero())
 	}
 }
 
@@ -451,7 +461,7 @@ where
 moonbeam_runtime_common::impl_on_charge_evm_transaction!();
 
 impl pallet_evm::Config for Runtime {
-	type FeeCalculator = FixedGasPrice;
+	type FeeCalculator = TransactionPaymentAsGasPrice;
 	type GasWeightMapping = pallet_evm::FixedGasWeightMapping<Self>;
 	type WeightPerGas = WeightPerGas;
 	type BlockHashMapping = pallet_ethereum::EthereumBlockHashMapping<Self>;
@@ -1131,7 +1141,7 @@ construct_runtime! {
 		Sudo: pallet_sudo::{Pallet, Call, Config<T>, Storage, Event<T>} = 4,
 		RandomnessCollectiveFlip: pallet_randomness_collective_flip::{Pallet, Storage} = 5,
 		ParachainSystem: cumulus_pallet_parachain_system::{Pallet, Call, Storage, Inherent, Event<T>} = 6,
-		TransactionPayment: pallet_transaction_payment::{Pallet, Storage, Event<T>} = 7,
+		TransactionPayment: pallet_transaction_payment::{Pallet, Storage, Config, Event<T>} = 7,
 		ParachainInfo: parachain_info::{Pallet, Storage, Config} = 8,
 		EthereumChainId: pallet_ethereum_chain_id::{Pallet, Storage, Config} = 9,
 		EVM: pallet_evm::{Pallet, Config, Call, Storage, Event<T>} = 10,
@@ -1389,7 +1399,6 @@ mod tests {
 			5_u8
 		);
 		assert_eq!(STORAGE_BYTE_FEE, Balance::from(100 * MICROUNIT));
-		assert_eq!(FixedGasPrice::min_gas_price().0, (1 * GIGAWEI).into());
 
 		// democracy minimums
 		assert_eq!(

runtime/moonbase/tests/common/mod.rs

@@ -27,9 +27,9 @@ use moonbase_runtime::{asset_config::AssetRegistrarMetadata, xcm_config::AssetTy
 pub use moonbase_runtime::{
 	currency::{GIGAWEI, SUPPLY_FACTOR, UNIT, WEI},
 	AccountId, AssetId, AssetManager, Assets, AuthorInherent, Balance, Balances, CrowdloanRewards,
-	Ethereum, Executive, FixedGasPrice, InflationInfo, LocalAssets, ParachainStaking, Range,
-	Runtime, RuntimeCall, RuntimeEvent, System, TransactionConverter, UncheckedExtrinsic, HOURS,
-	WEEKS,
+	Ethereum, Executive, InflationInfo, LocalAssets, ParachainStaking, Range, Runtime, RuntimeCall,
+	RuntimeEvent, System, TransactionConverter, TransactionPaymentAsGasPrice, UncheckedExtrinsic,
+	HOURS, WEEKS,
 };
 use nimbus_primitives::{NimbusId, NIMBUS_ENGINE_ID};
 use sp_core::{Encode, H160};
@@ -38,12 +38,13 @@ use sp_runtime::{Digest, DigestItem, Perbill, Percent};
 use std::collections::BTreeMap;
 
 use fp_rpc::ConvertTransaction;
+use pallet_transaction_payment::Multiplier;
 
 // A valid signed Alice transfer.
 pub const VALID_ETH_TX: &str =
-	"f86880843b9aca0083b71b0094111111111111111111111111111111111111111182020080820a26a\
-	08c69faf613b9f72dbb029bb5d5acf42742d214c79743507e75fdc8adecdee928a001be4f58ff278ac\
-	61125a81a582a717d9c5d6554326c01b878297c6522b12282";
+	"02f86d8205018085174876e80085e8d4a5100082520894f24ff3a9cf04c71dbc94d0b566f7a27b9456\
+	6cac8080c001a0e1094e1a52520a75c0255db96132076dd0f1263089f838bea548cbdbfc64a4d19f031c\
+	92a8cb04e2d68d20a6158d542a07ac440cc8d07b6e36af02db046d92df";
 
 // An invalid signed Alice transfer with a gas limit artifically set to 0.
 pub const INVALID_ETH_TX: &str =
@@ -291,6 +292,14 @@ impl ExtBuilder {
 		)
 		.unwrap();
 
+		<pallet_transaction_payment::GenesisConfig as GenesisBuild<Runtime>>::assimilate_storage(
+			&pallet_transaction_payment::GenesisConfig {
+				multiplier: Multiplier::from(8u128),
+			},
+			&mut t,
+		)
+		.unwrap();
+
 		let mut ext = sp_io::TestExternalities::new(t);
 
 		let local_assets = self.local_assets.clone();