reduce exec time of fast-unstake benchmarks (#13120)

* reduce exec time of fast-unstake benchmarks

* fix test

* fmt

* fix patch the tests

* fix patch the tests

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_fast_unstake

* add batch size as well

* update some benches to be better

* fix one last test

* fix

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_fast_unstake

* reduce time even more

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_fast_unstake

* fix tests

* nit

* remove

* improve the weight calc further

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_fast_unstake

* fix benchmarks

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_fast_unstake

* update

* fix

* fix

* fmt

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_fast_unstake

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_fast_unstake

* lots of changes again...

* smaller input

* update

* fmt

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_fast_unstake

* cleanup

* small simplification

* fmt

* reduce exec time a bit

* fix

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_fast_unstake

* test

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_fast_unstake

* increase again

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_fast_unstake

* review comments

* fmt

* fix

* ".git/.scripts/commands/bench/bench.sh" pallet dev pallet_fast_unstake

Co-authored-by: command-bot <>

bin/node/runtime/src/lib.rs

@@ -591,10 +591,13 @@ impl pallet_staking::Config for Runtime {
 impl pallet_fast_unstake::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type ControlOrigin = frame_system::EnsureRoot<AccountId>;
-	type BatchSize = ConstU32<128>;
+	type BatchSize = ConstU32<64>;
 	type Deposit = ConstU128<{ DOLLARS }>;
 	type Currency = Balances;
 	type Staking = Staking;
+	type MaxErasToCheckPerBlock = ConstU32<1>;
+	#[cfg(feature = "runtime-benchmarks")]
+	type MaxBackersPerValidator = MaxNominatorRewardedPerValidator;
 	type WeightInfo = ();
 }
 

frame/fast-unstake/src/benchmarking.rs

@@ -31,13 +31,11 @@ use sp_staking::{EraIndex, StakingInterface};
 use sp_std::prelude::*;
 
 const USER_SEED: u32 = 0;
-const DEFAULT_BACKER_PER_VALIDATOR: u32 = 128;
-const MAX_VALIDATORS: u32 = 128;
 
 type CurrencyOf<T> = <T as Config>::Currency;
 
-fn create_unexposed_nominators<T: Config>() -> Vec<T::AccountId> {
-	(0..T::BatchSize::get())
+fn create_unexposed_batch<T: Config>(batch_size: u32) -> Vec<T::AccountId> {
+	(0..batch_size)
 		.map(|i| {
 			let account =
 				frame_benchmarking::account::<T::AccountId>("unexposed_nominator", i, USER_SEED);
@@ -76,7 +74,7 @@ fn setup_staking<T: Config>(v: u32, until: EraIndex) {
 		.collect::<Vec<_>>();
 
 	for era in 0..=until {
-		let others = (0..DEFAULT_BACKER_PER_VALIDATOR)
+		let others = (0..T::MaxBackersPerValidator::get())
 			.map(|s| {
 				let who = frame_benchmarking::account::<T::AccountId>("nominator", era, s);
 				let value = ed;
@@ -97,8 +95,10 @@ fn on_idle_full_block<T: Config>() {
 benchmarks! {
 	// on_idle, we don't check anyone, but fully unbond them.
 	on_idle_unstake {
+		let b in 1 .. T::BatchSize::get();
+
 		ErasToCheckPerBlock::<T>::put(1);
-		for who in create_unexposed_nominators::<T>() {
+		for who in create_unexposed_batch::<T>(b).into_iter() {
 			assert_ok!(FastUnstake::<T>::register_fast_unstake(
 				RawOrigin::Signed(who.clone()).into(),
 			));
@@ -114,7 +114,7 @@ benchmarks! {
 				checked,
 				stashes,
 				..
-			}) if checked.len() == 1 && stashes.len() as u32 == T::BatchSize::get()
+			}) if checked.len() == 1 && stashes.len() as u32 == b
 		));
 	}
 	: {
@@ -123,25 +123,23 @@ benchmarks! {
 	verify {
 		assert!(matches!(
 			fast_unstake_events::<T>().last(),
-			Some(Event::BatchFinished)
+			Some(Event::BatchFinished { size: b })
 		));
 	}
 
-	// on_idle, when we check some number of eras,
+	// on_idle, when we check some number of eras and the queue is already set.
 	on_idle_check {
-		// number of eras multiplied by validators in that era.
-		let x in (T::Staking::bonding_duration() * 1) .. (T::Staking::bonding_duration() * MAX_VALIDATORS);
-
-		let u = T::Staking::bonding_duration();
-		let v = x / u;
+		let v in 1 .. 256;
+		let b in 1 .. T::BatchSize::get();
+		let u = T::MaxErasToCheckPerBlock::get().min(T::Staking::bonding_duration());
 
 		ErasToCheckPerBlock::<T>::put(u);
 		T::Staking::set_current_era(u);
 
-		// setup staking with v validators and u eras of data (0..=u)
+		// setup staking with v validators and u eras of data (0..=u+1)
 		setup_staking::<T>(v, u);
 
-		let stashes = create_unexposed_nominators::<T>().into_iter().map(|s| {
+		let stashes = create_unexposed_batch::<T>(b).into_iter().map(|s| {
 			assert_ok!(FastUnstake::<T>::register_fast_unstake(
 				RawOrigin::Signed(s.clone()).into(),
 			));
@@ -150,6 +148,8 @@ benchmarks! {
 
 		// no one is queued thus far.
 		assert_eq!(Head::<T>::get(), None);
+
+		Head::<T>::put(UnstakeRequest { stashes: stashes.clone().try_into().unwrap(), checked: Default::default() });
 	}
 	: {
 		on_idle_full_block::<T>();
@@ -167,7 +167,7 @@ benchmarks! {
 
 	register_fast_unstake {
 		ErasToCheckPerBlock::<T>::put(1);
-		let who = create_unexposed_nominators::<T>().get(0).cloned().unwrap();
+		let who = create_unexposed_batch::<T>(1).get(0).cloned().unwrap();
 		whitelist_account!(who);
 		assert_eq!(Queue::<T>::count(), 0);
 
@@ -179,7 +179,7 @@ benchmarks! {
 
 	deregister {
 		ErasToCheckPerBlock::<T>::put(1);
-		let who = create_unexposed_nominators::<T>().get(0).cloned().unwrap();
+		let who = create_unexposed_batch::<T>(1).get(0).cloned().unwrap();
 		assert_ok!(FastUnstake::<T>::register_fast_unstake(
 			RawOrigin::Signed(who.clone()).into(),
 		));
@@ -194,7 +194,7 @@ benchmarks! {
 	control {
 		let origin = <T as Config>::ControlOrigin::successful_origin();
 	}
-	: _<T::RuntimeOrigin>(origin, 128)
+	: _<T::RuntimeOrigin>(origin, T::MaxErasToCheckPerBlock::get())
 	verify {}
 
 	impl_benchmark_test_suite!(Pallet, crate::mock::ExtBuilder::default().build(), crate::mock::Runtime)

frame/fast-unstake/src/lib.rs

@@ -86,12 +86,9 @@ pub mod pallet {
 		traits::{Defensive, ReservableCurrency, StorageVersion},
 	};
 	use frame_system::pallet_prelude::*;
-	use sp_runtime::{
-		traits::{Saturating, Zero},
-		DispatchResult,
-	};
+	use sp_runtime::{traits::Zero, DispatchResult};
 	use sp_staking::{EraIndex, StakingInterface};
-	use sp_std::{collections::btree_set::BTreeSet, prelude::*, vec::Vec};
+	use sp_std::{prelude::*, vec::Vec};
 	pub use weights::WeightInfo;
 
 	#[derive(scale_info::TypeInfo, codec::Encode, codec::Decode, codec::MaxEncodedLen)]
@@ -138,6 +135,14 @@ pub mod pallet {
 
 		/// The weight information of this pallet.
 		type WeightInfo: WeightInfo;
+
+		/// Maximum value for `ErasToCheckPerBlock`. This should be as close as possible, but more
+		/// than the actual value, in order to have accurate benchmarks.
+		type MaxErasToCheckPerBlock: Get<u32>;
+
+		/// Use only for benchmarking.
+		#[cfg(feature = "runtime-benchmarks")]
+		type MaxBackersPerValidator: Get<u32>;
 	}
 
 	/// The current "head of the queue" being unstaked.
@@ -173,11 +178,11 @@ pub mod pallet {
 		InternalError,
 		/// A batch was partially checked for the given eras, but the process did not finish.
 		BatchChecked { eras: Vec<EraIndex> },
-		/// A batch was terminated.
+		/// A batch of a given size was terminated.
 		///
 		/// This is always follows by a number of `Unstaked` or `Slashed` events, marking the end
 		/// of the batch. A new batch will be created upon next block.
-		BatchFinished,
+		BatchFinished { size: u32 },
 	}
 
 	#[pallet::error]
@@ -208,6 +213,31 @@ pub mod pallet {
 
 			Self::do_on_idle(remaining_weight)
 		}
+
+		fn integrity_test() {
+			sp_std::if_std! {
+				sp_io::TestExternalities::new_empty().execute_with(|| {
+					// ensure that the value of `ErasToCheckPerBlock` is less than
+					// `T::MaxErasToCheckPerBlock`.
+					assert!(
+						ErasToCheckPerBlock::<T>::get() <= T::MaxErasToCheckPerBlock::get(),
+						"the value of `ErasToCheckPerBlock` is greater than `T::MaxErasToCheckPerBlock`",
+					);
+				});
+			}
+		}
+
+		#[cfg(feature = "try-runtime")]
+		fn try_state(_n: T::BlockNumber) -> Result<(), &'static str> {
+			// ensure that the value of `ErasToCheckPerBlock` is less than
+			// `T::MaxErasToCheckPerBlock`.
+			assert!(
+				ErasToCheckPerBlock::<T>::get() <= T::MaxErasToCheckPerBlock::get(),
+				"the value of `ErasToCheckPerBlock` is greater than `T::MaxErasToCheckPerBlock`",
+			);
+
+			Ok(())
+		}
 	}
 
 	#[pallet::call]
@@ -288,9 +318,10 @@ pub mod pallet {
 		/// Dispatch origin must be signed by the [`Config::ControlOrigin`].
 		#[pallet::call_index(2)]
 		#[pallet::weight(<T as Config>::WeightInfo::control())]
-		pub fn control(origin: OriginFor<T>, unchecked_eras_to_check: EraIndex) -> DispatchResult {
+		pub fn control(origin: OriginFor<T>, eras_to_check: EraIndex) -> DispatchResult {
 			let _ = T::ControlOrigin::ensure_origin(origin)?;
-			ErasToCheckPerBlock::<T>::put(unchecked_eras_to_check);
+			ensure!(eras_to_check <= T::MaxErasToCheckPerBlock::get(), Error::<T>::CallNotAllowed);
+			ErasToCheckPerBlock::<T>::put(eras_to_check);
 			Ok(())
 		}
 	}
@@ -324,35 +355,46 @@ pub mod pallet {
 		/// found out to have no eras to check. At the end of a check cycle, even if they are fully
 		/// checked, we don't finish the process.
 		pub(crate) fn do_on_idle(remaining_weight: Weight) -> Weight {
-			let mut eras_to_check_per_block = ErasToCheckPerBlock::<T>::get();
+			// any weight that is unaccounted for
+			let mut unaccounted_weight = Weight::from_ref_time(0);
+
+			let eras_to_check_per_block = ErasToCheckPerBlock::<T>::get();
 			if eras_to_check_per_block.is_zero() {
-				return T::DbWeight::get().reads(1)
+				return T::DbWeight::get().reads(1).saturating_add(unaccounted_weight)
 			}
 
 			// NOTE: here we're assuming that the number of validators has only ever increased,
 			// meaning that the number of exposures to check is either this per era, or less.
 			let validator_count = T::Staking::desired_validator_count();
+			let (next_batch_size, reads_from_queue) = Head::<T>::get()
+				.map_or((Queue::<T>::count().min(T::BatchSize::get()), true), |head| {
+					(head.stashes.len() as u32, false)
+				});
 
 			// determine the number of eras to check. This is based on both `ErasToCheckPerBlock`
 			// and `remaining_weight` passed on to us from the runtime executive.
-			let max_weight = |v, u| {
-				<T as Config>::WeightInfo::on_idle_check(v * u)
-					.max(<T as Config>::WeightInfo::on_idle_unstake())
+			let max_weight = |v, b| {
+				// NOTE: this potentially under-counts by up to `BatchSize` reads from the queue.
+				<T as Config>::WeightInfo::on_idle_check(v, b)
+					.max(<T as Config>::WeightInfo::on_idle_unstake(b))
+					.saturating_add(if reads_from_queue {
+						T::DbWeight::get().reads(next_batch_size.into())
+					} else {
+						Zero::zero()
+					})
 			};
-			while max_weight(validator_count, eras_to_check_per_block).any_gt(remaining_weight) {
-				eras_to_check_per_block.saturating_dec();
-				if eras_to_check_per_block.is_zero() {
-					log!(debug, "early existing because eras_to_check_per_block is zero");
-					return T::DbWeight::get().reads(2)
-				}
+
+			if max_weight(validator_count, next_batch_size).any_gt(remaining_weight) {
+				log!(debug, "early exit because eras_to_check_per_block is zero");
+				return T::DbWeight::get().reads(3).saturating_add(unaccounted_weight)
 			}
 
 			if T::Staking::election_ongoing() {
 				// NOTE: we assume `ongoing` does not consume any weight.
 				// there is an ongoing election -- we better not do anything. Imagine someone is not
 				// exposed anywhere in the last era, and the snapshot for the election is already
 				// taken. In this time period, we don't want to accidentally unstake them.
-				return T::DbWeight::get().reads(2)
+				return T::DbWeight::get().reads(4).saturating_add(unaccounted_weight)
 			}
 
 			let UnstakeRequest { stashes, mut checked } = match Head::<T>::take().or_else(|| {
@@ -362,6 +404,9 @@ pub mod pallet {
 					.collect::<Vec<_>>()
 					.try_into()
 					.expect("take ensures bound is met; qed");
+				unaccounted_weight.saturating_accrue(
+					T::DbWeight::get().reads_writes(stashes.len() as u64, stashes.len() as u64),
+				);
 				if stashes.is_empty() {
 					None
 				} else {
@@ -377,10 +422,11 @@ pub mod pallet {
 
 			log!(
 				debug,
-				"checking {:?} stashes, eras_to_check_per_block = {:?}, remaining_weight = {:?}",
+				"checking {:?} stashes, eras_to_check_per_block = {:?}, checked {:?}, remaining_weight = {:?}",
 				stashes.len(),
 				eras_to_check_per_block,
-				remaining_weight
+				checked,
+				remaining_weight,
 			);
 
 			// the range that we're allowed to check in this round.
@@ -431,11 +477,10 @@ pub mod pallet {
 				}
 			};
 
-			let check_stash = |stash, deposit, eras_checked: &mut BTreeSet<EraIndex>| {
-				let is_exposed = unchecked_eras_to_check.iter().any(|e| {
-					eras_checked.insert(*e);
-					T::Staking::is_exposed_in_era(&stash, e)
-				});
+			let check_stash = |stash, deposit| {
+				let is_exposed = unchecked_eras_to_check
+					.iter()
+					.any(|e| T::Staking::is_exposed_in_era(&stash, e));
 
 				if is_exposed {
 					T::Currency::slash_reserved(&stash, deposit);
@@ -448,37 +493,33 @@ pub mod pallet {
 			};
 
 			if unchecked_eras_to_check.is_empty() {
-				// `stash` is not exposed in any era now -- we can let go of them now.
+				// `stashes` are not exposed in any era now -- we can let go of them now.
+				let size = stashes.len() as u32;
 				stashes.into_iter().for_each(|(stash, deposit)| unstake_stash(stash, deposit));
-				Self::deposit_event(Event::<T>::BatchFinished);
-				<T as Config>::WeightInfo::on_idle_unstake()
+				Self::deposit_event(Event::<T>::BatchFinished { size });
+				<T as Config>::WeightInfo::on_idle_unstake(size).saturating_add(unaccounted_weight)
 			} else {
-				// eras checked so far.
-				let mut eras_checked = BTreeSet::<EraIndex>::new();
-
 				let pre_length = stashes.len();
 				let stashes: BoundedVec<(T::AccountId, BalanceOf<T>), T::BatchSize> = stashes
 					.into_iter()
-					.filter(|(stash, deposit)| {
-						check_stash(stash.clone(), *deposit, &mut eras_checked)
-					})
+					.filter(|(stash, deposit)| check_stash(stash.clone(), *deposit))
 					.collect::<Vec<_>>()
 					.try_into()
 					.expect("filter can only lessen the length; still in bound; qed");
 				let post_length = stashes.len();
 
 				log!(
 					debug,
-					"checked {:?} eras, pre stashes: {:?}, post: {:?}",
-					eras_checked.len(),
+					"checked {:?}, pre stashes: {:?}, post: {:?}",
+					unchecked_eras_to_check,
 					pre_length,
 					post_length,
 				);
 
 				match checked.try_extend(unchecked_eras_to_check.clone().into_iter()) {
 					Ok(_) =>
 						if stashes.is_empty() {
-							Self::deposit_event(Event::<T>::BatchFinished);
+							Self::deposit_event(Event::<T>::BatchFinished { size: 0 });
 						} else {
 							Head::<T>::put(UnstakeRequest { stashes, checked });
 							Self::deposit_event(Event::<T>::BatchChecked {
@@ -491,9 +532,8 @@ pub mod pallet {
 					},
 				}
 
-				<T as Config>::WeightInfo::on_idle_check(
-					validator_count * eras_checked.len() as u32,
-				)
+				<T as Config>::WeightInfo::on_idle_check(validator_count, pre_length as u32)
+					.saturating_add(unaccounted_weight)
 			}
 		}
 	}

frame/fast-unstake/src/mock.rs

@@ -185,6 +185,9 @@ impl fast_unstake::Config for Runtime {
 	type ControlOrigin = frame_system::EnsureRoot<Self::AccountId>;
 	type BatchSize = BatchSize;
 	type WeightInfo = ();
+	type MaxErasToCheckPerBlock = ConstU32<16>;
+	#[cfg(feature = "runtime-benchmarks")]
+	type MaxBackersPerValidator = ConstU32<128>;
 }
 
 type Block = frame_system::mocking::MockBlock<Runtime>;