Improve staking payout performance

pallet/account-migration/src/mock.rs

@@ -160,12 +160,13 @@ impl darwinia_deposit::Config for Runtime {
 }
 
 impl darwinia_staking::Config for Runtime {
+	type Currency = Balances;
 	type Deposit = Deposit;
+	type InflationManager = ();
 	type Kton = Dummy;
 	type MaxDeposits = ();
 	type MaxUnstakings = ();
 	type MinStakingDuration = ();
-	type OnSessionEnd = ();
 	type Ring = Dummy;
 	type RuntimeEvent = RuntimeEvent;
 	type WeightInfo = ();

pallet/staking/Cargo.toml

@@ -37,7 +37,7 @@ darwinia-deposit = { workspace = true, features = ["std"] }
 
 # substrate
 dc-inflation         = { workspace = true, features = ["std"] }
-pallet-assets        = { workspace = true, features = ["std"] }
+pallet-assets        = { workspace = true, features = ["runtime-benchmarks", "std"] }
 pallet-balances      = { workspace = true, features = ["std"] }
 pallet-session       = { workspace = true, features = ["std"] }
 pallet-timestamp     = { workspace = true, features = ["std"] }

pallet/staking/src/benchmarking.rs

@@ -198,6 +198,30 @@ mod benchmarks {
 		_(RawOrigin::Signed(a));
 	}
 
+	#[benchmark]
+	fn payout() {
+		let a = frame_benchmarking::whitelisted_caller::<T::AccountId>();
+		let sender = a.clone();
+
+		<PreviousExposures<T>>::insert(
+			&a,
+			Exposure {
+				commission: Perbill::zero(),
+				vote: 32,
+				nominators: (0..32)
+					.map(|i| IndividualExposure {
+						who: frame_benchmarking::account("", i, i),
+						vote: 1,
+					})
+					.collect(),
+			},
+		);
+		<Unpaid<T>>::insert(&a, 500);
+
+		#[extrinsic_call]
+		_(RawOrigin::Signed(sender), a);
+	}
+
 	#[benchmark]
 	fn set_collator_count() {
 		// Worst-case scenario: