Add Dynamic Fee support for Moonriver

node/service/src/chain_spec/moonriver.rs

@@ -328,7 +328,7 @@ 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),
+			multiplier: Multiplier::from(10u128),
 		},
 	}
 }

runtime/moonriver/src/lib.rs

@@ -191,7 +191,7 @@ 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.
@@ -374,25 +374,40 @@ 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::from(1u128);
 	/// 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: MoonriverPrecompiles<Runtime> = MoonriverPrecompiles::<_>::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) {
+		// note: 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));
 		(
-			(1 * currency::GIGAWEI * currency::SUPPLY_FACTOR).into(),
+			min_gas_price.into(),
 			<Runtime as frame_system::Config>::DbWeight::get().reads(1),
 		)
 	}
@@ -440,7 +455,7 @@ 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>;

runtime/moonriver/tests/common/mod.rs

@@ -28,9 +28,9 @@ pub use moonriver_runtime::{
 	currency::{GIGAWEI, MOVR, SUPPLY_FACTOR, WEI},
 	xcm_config::AssetType,
 	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};
@@ -39,12 +39,13 @@ 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 =
@@ -303,6 +304,14 @@ impl ExtBuilder {
 		)
 		.unwrap();
 
+		<pallet_transaction_payment::GenesisConfig as GenesisBuild<Runtime>>::assimilate_storage(
+			&pallet_transaction_payment::GenesisConfig {
+				multiplier: Multiplier::from(10u128),
+			},
+			&mut t,
+		)
+		.unwrap();
+
 		let mut ext = sp_io::TestExternalities::new(t);
 		let local_assets = self.local_assets.clone();
 		let xcm_assets = self.xcm_assets.clone();

runtime/moonriver/tests/integration_test.rs

@@ -21,7 +21,7 @@
 mod common;
 use common::*;
 
-use fp_evm::{Context, FeeCalculator};
+use fp_evm::Context;
 use frame_support::{
 	assert_noop, assert_ok,
 	dispatch::{DispatchClass, Dispatchable},
@@ -35,14 +35,16 @@ use frame_support::{
 use moonriver_runtime::{
 	asset_config::LocalAssetInstance,
 	xcm_config::{CurrencyId, SelfReserve, UnitWeightCost},
-	AssetId, LocalAssets, PolkadotXcm, Precompiles, RuntimeBlockWeights, XTokens, XcmTransactor,
-	FOREIGN_ASSET_PRECOMPILE_ADDRESS_PREFIX, LOCAL_ASSET_PRECOMPILE_ADDRESS_PREFIX,
+	AssetId, LocalAssets, PolkadotXcm, Precompiles, RuntimeBlockWeights, TransactionPayment,
+	XTokens, XcmTransactor, FOREIGN_ASSET_PRECOMPILE_ADDRESS_PREFIX,
+	LOCAL_ASSET_PRECOMPILE_ADDRESS_PREFIX,
 };
 use nimbus_primitives::NimbusId;
 use pallet_evm::PrecompileSet;
 use pallet_evm_precompileset_assets_erc20::{
 	AccountIdAssetIdConversion, IsLocal, SELECTOR_LOG_APPROVAL, SELECTOR_LOG_TRANSFER,
 };
+use pallet_transaction_payment::Multiplier;
 use pallet_xcm_transactor::{Currency, CurrencyPayment, TransactWeights};
 use parity_scale_codec::Encode;
 use polkadot_parachain::primitives::Sibling;
@@ -72,6 +74,8 @@ type LocalAssetsPCall = pallet_evm_precompileset_assets_erc20::Erc20AssetsPrecom
 type XcmTransactorV1PCall =
 	pallet_evm_precompile_xcm_transactor::v1::XcmTransactorPrecompileV1Call<Runtime>;
 
+const BASE_FEE_GENESIS: u128 = 100 * GIGAWEI;
+
 #[test]
 fn xcmp_queue_controller_origin_is_root() {
 	// important for the XcmExecutionManager impl of PauseExecution which uses root origin
@@ -439,7 +443,7 @@ fn transfer_through_evm_to_stake() {
 			assert_eq!(Balances::free_balance(AccountId::from(BOB)), 2_000 * MOVR);
 
 			let gas_limit = 100000u64;
-			let gas_price: U256 = 1_000_000_000u64.into();
+			let gas_price: U256 = BASE_FEE_GENESIS.into();
 			// Bob transfers 1000 MOVR to Charlie via EVM
 			assert_ok!(RuntimeCall::EVM(pallet_evm::Call::<Runtime>::call {
 				source: H160::from(BOB),
@@ -845,7 +849,7 @@ fn claim_via_precompile() {
 
 			// Alice uses the crowdloan precompile to claim through the EVM
 			let gas_limit = 100000u64;
-			let gas_price: U256 = 1_000_000_000u64.into();
+			let gas_price: U256 = BASE_FEE_GENESIS.into();
 
 			// Construct the call data (selector, amount)
 			let mut call_data = Vec::<u8>::from([0u8; 4]);
@@ -1091,7 +1095,7 @@ fn update_reward_address_via_precompile() {
 
 			// Charlie uses the crowdloan precompile to update address through the EVM
 			let gas_limit = 100000u64;
-			let gas_price: U256 = 1_000_000_000u64.into();
+			let gas_price: U256 = BASE_FEE_GENESIS.into();
 
 			// Construct the input data to check if Bob is a contributor
 			let mut call_data = Vec::<u8>::from([0u8; 36]);
@@ -1211,6 +1215,46 @@ fn ethereum_invalid_transaction() {
 	});
 }
 
+#[test]
+fn initial_gas_fee_is_correct() {
+	use fp_evm::FeeCalculator;
+
+	ExtBuilder::default().build().execute_with(|| {
+		let multiplier = TransactionPayment::next_fee_multiplier();
+		assert_eq!(multiplier, Multiplier::from(10u128));
+
+		assert_eq!(
+			TransactionPaymentAsGasPrice::min_gas_price(),
+			(
+				12_500_000_000u128.into(),
+				Weight::from_ref_time(25_000_000u64)
+			)
+		);
+	});
+}
+
+#[test]
+fn min_gas_fee_is_correct() {
+	use fp_evm::FeeCalculator;
+	use frame_support::traits::Hooks;
+
+	ExtBuilder::default().build().execute_with(|| {
+		pallet_transaction_payment::NextFeeMultiplier::<Runtime>::put(Multiplier::from(0));
+		TransactionPayment::on_finalize(System::block_number()); // should trigger min to kick in
+
+		let multiplier = TransactionPayment::next_fee_multiplier();
+		assert_eq!(multiplier, Multiplier::from(1u128));
+
+		assert_eq!(
+			TransactionPaymentAsGasPrice::min_gas_price(),
+			(
+				1_250_000_000u128.into(),
+				Weight::from_ref_time(25_000_000u64)
+			)
+		);
+	});
+}
+
 #[test]
 fn transfer_ed_0_substrate() {
 	ExtBuilder::default()
@@ -1237,7 +1281,7 @@ fn transfer_ed_0_evm() {
 		.with_balances(vec![
 			(
 				AccountId::from(ALICE),
-				((1 * MOVR) + (21_000 * 1_000_000_000)) + (1 * WEI),
+				((1 * MOVR) + (21_000 * BASE_FEE_GENESIS)) + (1 * WEI),
 			),
 			(AccountId::from(BOB), 0),
 		])
@@ -1250,8 +1294,8 @@ fn transfer_ed_0_evm() {
 				input: Vec::new(),
 				value: (1 * MOVR).into(),
 				gas_limit: 21_000u64,
-				max_fee_per_gas: U256::from(1_000_000_000),
-				max_priority_fee_per_gas: None,
+				max_fee_per_gas: U256::from(BASE_FEE_GENESIS),
+				max_priority_fee_per_gas: Some(U256::from(BASE_FEE_GENESIS)),
 				nonce: Some(U256::from(0)),
 				access_list: Vec::new(),
 			})
@@ -1267,7 +1311,7 @@ fn refund_ed_0_evm() {
 		.with_balances(vec![
 			(
 				AccountId::from(ALICE),
-				((1 * MOVR) + (21_777 * 1_000_000_000)),
+				((1 * MOVR) + (21_777 * BASE_FEE_GENESIS)),
 			),
 			(AccountId::from(BOB), 0),
 		])
@@ -1280,16 +1324,16 @@ fn refund_ed_0_evm() {
 				input: Vec::new(),
 				value: (1 * MOVR).into(),
 				gas_limit: 21_777u64,
-				max_fee_per_gas: U256::from(1_000_000_000),
-				max_priority_fee_per_gas: None,
+				max_fee_per_gas: U256::from(BASE_FEE_GENESIS),
+				max_priority_fee_per_gas: Some(U256::from(BASE_FEE_GENESIS)),
 				nonce: Some(U256::from(0)),
 				access_list: Vec::new(),
 			})
 			.dispatch(<Runtime as frame_system::Config>::RuntimeOrigin::root()));
 			// ALICE is refunded
 			assert_eq!(
 				Balances::free_balance(AccountId::from(ALICE)),
-				777 * 1_000_000_000,
+				777 * BASE_FEE_GENESIS,
 			);
 		});
 }
@@ -1333,7 +1377,7 @@ fn total_issuance_after_evm_transaction_with_priority_fee() {
 	ExtBuilder::default()
 		.with_balances(vec![(
 			AccountId::from(BOB),
-			(1 * MOVR) + (21_000 * (2 * GIGAWEI)),
+			(1 * MOVR) + (21_000 * (2 * BASE_FEE_GENESIS)),
 		)])
 		.build()
 		.execute_with(|| {
@@ -1345,16 +1389,15 @@ fn total_issuance_after_evm_transaction_with_priority_fee() {
 				input: Vec::new(),
 				value: (1 * MOVR).into(),
 				gas_limit: 21_000u64,
-				max_fee_per_gas: U256::from(2 * GIGAWEI),
-				max_priority_fee_per_gas: Some(U256::from(1 * GIGAWEI)),
+				max_fee_per_gas: U256::from(2u128 * BASE_FEE_GENESIS),
+				max_priority_fee_per_gas: Some(U256::from(2u128 * BASE_FEE_GENESIS)),
 				nonce: Some(U256::from(0)),
 				access_list: Vec::new(),
 			})
 			.dispatch(<Runtime as frame_system::Config>::RuntimeOrigin::root()));
 
 			let issuance_after = <Runtime as pallet_evm::Config>::Currency::total_issuance();
-			// Fee is 1 GWEI base fee + 1 GWEI tip.
-			let fee = ((2 * GIGAWEI) * 21_000) as f64;
+			let fee = ((2 * BASE_FEE_GENESIS) * 21_000) as f64;
 			// 80% was burned.
 			let expected_burn = (fee * 0.8) as u128;
 			assert_eq!(issuance_after, issuance_before - expected_burn,);
@@ -1369,7 +1412,7 @@ fn total_issuance_after_evm_transaction_without_priority_fee() {
 	ExtBuilder::default()
 		.with_balances(vec![(
 			AccountId::from(BOB),
-			(1 * MOVR) + (21_000 * (2 * GIGAWEI)),
+			(1 * MOVR) + (21_000 * (2 * BASE_FEE_GENESIS)),
 		)])
 		.build()
 		.execute_with(|| {
@@ -1381,16 +1424,15 @@ fn total_issuance_after_evm_transaction_without_priority_fee() {
 				input: Vec::new(),
 				value: (1 * MOVR).into(),
 				gas_limit: 21_000u64,
-				max_fee_per_gas: U256::from(1 * GIGAWEI),
-				max_priority_fee_per_gas: None,
+				max_fee_per_gas: U256::from(BASE_FEE_GENESIS),
+				max_priority_fee_per_gas: Some(U256::from(BASE_FEE_GENESIS)),
 				nonce: Some(U256::from(0)),
 				access_list: Vec::new(),
 			})
 			.dispatch(<Runtime as frame_system::Config>::RuntimeOrigin::root()));
 
 			let issuance_after = <Runtime as pallet_evm::Config>::Currency::total_issuance();
-			// Fee is 1 GWEI base fee.
-			let fee = ((1 * GIGAWEI) * 21_000) as f64;
+			let fee = ((1 * BASE_FEE_GENESIS) * 21_000) as f64;
 			// 80% was burned.
 			let expected_burn = (fee * 0.8) as u128;
 			assert_eq!(issuance_after, issuance_before - expected_burn,);
@@ -2804,15 +2846,6 @@ fn precompile_existence() {
 	});
 }
 
-#[test]
-fn base_fee_should_default_to_associate_type_value() {
-	ExtBuilder::default().build().execute_with(|| {
-		let (base_fee, _) =
-			<moonriver_runtime::Runtime as pallet_evm::Config>::FeeCalculator::min_gas_price();
-		assert_eq!(base_fee, (1 * GIGAWEI * SUPPLY_FACTOR).into());
-	});
-}
-
 #[test]
 fn evm_revert_substrate_events() {
 	ExtBuilder::default()
@@ -2835,7 +2868,7 @@ fn evm_revert_substrate_events() {
 				.into(),
 				value: U256::zero(), // No value sent in EVM
 				gas_limit: 500_000,
-				max_fee_per_gas: U256::from(1 * GIGAWEI),
+				max_fee_per_gas: U256::from(BASE_FEE_GENESIS),
 				max_priority_fee_per_gas: None,
 				nonce: Some(U256::from(0)),
 				access_list: Vec::new(),
@@ -2874,7 +2907,7 @@ fn evm_success_keeps_substrate_events() {
 				.into(),
 				value: U256::zero(), // No value sent in EVM
 				gas_limit: 500_000,
-				max_fee_per_gas: U256::from(1 * GIGAWEI),
+				max_fee_per_gas: U256::from(BASE_FEE_GENESIS),
 				max_priority_fee_per_gas: None,
 				nonce: Some(U256::from(0)),
 				access_list: Vec::new(),

runtime/moonriver/tests/runtime_apis.rs

@@ -54,7 +54,10 @@ fn ethereum_runtime_rpc_api_account_basic() {
 #[test]
 fn ethereum_runtime_rpc_api_gas_price() {
 	ExtBuilder::default().build().execute_with(|| {
-		assert_eq!(Runtime::gas_price(), FixedGasPrice::min_gas_price().0);
+		assert_eq!(
+			Runtime::gas_price(),
+			TransactionPaymentAsGasPrice::min_gas_price().0
+		);
 	});
 }
 
@@ -186,7 +189,7 @@ fn ethereum_runtime_rpc_api_create() {
 #[test]
 fn ethereum_runtime_rpc_api_current_transaction_statuses() {
 	let alith = <Runtime as pallet_evm::Config>::AddressMapping::into_account_id(
-		H160::from_str("6be02d1d3665660d22ff9624b7be0551ee1ac91b")
+		H160::from_str("f24ff3a9cf04c71dbc94d0b566f7a27b94566cac")
 			.expect("internal H160 is valid; qed"),
 	);
 	ExtBuilder::default()
@@ -249,7 +252,7 @@ fn ethereum_runtime_rpc_api_current_block() {
 #[test]
 fn ethereum_runtime_rpc_api_current_receipts() {
 	let alith = <Runtime as pallet_evm::Config>::AddressMapping::into_account_id(
-		H160::from_str("6be02d1d3665660d22ff9624b7be0551ee1ac91b")
+		H160::from_str("f24ff3a9cf04c71dbc94d0b566f7a27b94566cac")
 			.expect("internal H160 is valid; qed"),
 	);
 	ExtBuilder::default()