Benchmark Ethereum Pallet (#149)

* Add skeleton for worst case import_unsigned_header

* Fix a typo

* Add benchmark test for best case unsigned header import

* Add finality verification to worst case bench

* Move `insert_header()` from mock to test_utils

Allows the benchmarking code to use this without having to pull it in from the mock.

* Add a rough bench to test a finalizing a "long" chain

* Try to use complexity parameter for finality bench

* Improve long finality bench

* Remove stray dot file

* Remove old "worst" case bench

* Scribble some ideas down for pruning bench

* Prune headers during benchmarking

* Clean up some comments

* Make finality bench work for entire range of complexity parameter

* Place initialization code into a function

* Add bench for block finalization with caching

* First attempt at bench with receipts

* Try and trigger validator set change

* Perform a validator set change during benchmarking

* Move `validators_change_receipt()` to shared location

Allows unit tests and benchmarks to access the same helper function
and const

* Extract a test receipt root into a constant

* Clean up description of pruning bench

* Fix cache and pruning tests

* Remove unecessary `build_custom_header` usage

* Get rid of warnings

* Remove code duplication comment

I don't think its entirely worth it to split out so few lines of code.
The benches aren't particularly hard to read anyways.

* Increase the range of the complexity parameter

* Use dynamic number of receipts while benchmarking

As part of this change we have removed the hardcoded TEST_RECEIPT_ROOT
and instead chose to calculate the receipt root on the fly. This will
make tests and benches less fragile.

* Prune a dynamic number of headers

bin/node/runtime/src/lib.rs

@@ -215,6 +215,28 @@ impl pallet_aura::Trait for Runtime {
 	type AuthorityId = AuraId;
 }
 
+// We want to use a different validator configuration for benchmarking than what's used in Kovan,
+// but we can't configure a new validator set on the fly which means we need to wire the runtime
+// together like this
+#[cfg(feature = "runtime-benchmarks")]
+use pallet_bridge_eth_poa::{ValidatorsConfiguration, ValidatorsSource};
+
+#[cfg(feature = "runtime-benchmarks")]
+parameter_types! {
+	pub const FinalityVotesCachingInterval: Option<u64> = Some(16);
+	pub KovanAuraConfiguration: pallet_bridge_eth_poa::AuraConfiguration = kovan::kovan_aura_configuration();
+	pub KovanValidatorsConfiguration: pallet_bridge_eth_poa::ValidatorsConfiguration = bench_validator_config();
+}
+
+#[cfg(feature = "runtime-benchmarks")]
+fn bench_validator_config() -> ValidatorsConfiguration {
+	ValidatorsConfiguration::Multi(vec![
+		(0, ValidatorsSource::List(vec![[1; 20].into()])),
+		(1, ValidatorsSource::Contract([3; 20].into(), vec![[1; 20].into()])),
+	])
+}
+
+#[cfg(not(feature = "runtime-benchmarks"))]
 parameter_types! {
 	pub const FinalityVotesCachingInterval: Option<u64> = Some(16);
 	pub KovanAuraConfiguration: pallet_bridge_eth_poa::AuraConfiguration = kovan::kovan_aura_configuration();

modules/ethereum/src/benchmarking.rs

@@ -16,11 +16,14 @@
 
 use super::*;
 
-use crate::test_utils::{build_custom_header, build_genesis_header, validator_utils::*};
+use crate::test_utils::{
+	build_custom_header, build_genesis_header, insert_header, validator_utils::*, validators_change_receipt,
+	HeaderBuilder,
+};
 
 use frame_benchmarking::benchmarks;
 use frame_system::RawOrigin;
-use primitives::U256;
+use primitives::{compute_merkle_root, U256};
 
 benchmarks! {
 	_ { }
@@ -33,15 +36,8 @@ benchmarks! {
 	import_unsigned_header_best_case {
 		let n in 1..1000;
 
-		// initialize storage with some initial header
-		let initial_header = build_genesis_header(&validator(0));
-		let initial_header_hash = initial_header.compute_hash();
-		let initial_difficulty = initial_header.difficulty;
-		initialize_storage::<T>(
-			&initial_header,
-			initial_difficulty,
-			&validators_addresses(2),
-		);
+		let num_validators = 2;
+		let initial_header = initialize_bench::<T>(num_validators);
 
 		// prepare header to be inserted
 		let header = build_custom_header(
@@ -55,6 +51,223 @@ benchmarks! {
 
 	}: import_unsigned_header(RawOrigin::None, header, None)
 	verify {
-		assert_eq!(BridgeStorage::<T>::new().best_block().0.number, 1);
+		let storage = BridgeStorage::<T>::new();
+		assert_eq!(storage.best_block().0.number, 1);
+		assert_eq!(storage.finalized_block().number, 0);
+	}
+
+	// Our goal with this bench is to try and see the effect that finalizing difference ranges of
+	// blocks has on our import time. As such we need to make sure that we keep the number of
+	// validators fixed while changing the number blocks finalized (the complexity parameter) by
+	// importing the last header.
+	//
+	// One important thing to keep in mind is that the runtime provides a finality cache in order to
+	// reduce the overhead of header finalization. However, this is only triggered every 16 blocks.
+	import_unsigned_finality {
+		// Our complexity parameter, n, will represent the number of blocks imported before
+		// finalization.
+		let n in 1..7;
+
+		let mut storage = BridgeStorage::<T>::new();
+		let num_validators: u32 = 2;
+		let initial_header = initialize_bench::<T>(num_validators as usize);
+
+		// Since we only have two validators we need to make sure the number of blocks is even to
+		// make sure the right validator signs the final block
+		let num_blocks = 2 * n;
+		let mut headers = Vec::new();
+		let mut parent = initial_header.clone();
+
+		// Import a bunch of headers without any verification, will ensure that they're not
+		// finalized prematurely
+		for i in 1..=num_blocks {
+			let header = HeaderBuilder::with_parent(&parent).sign_by(&validator(0));
+			let id = header.compute_id();
+			insert_header(&mut storage, header.clone());
+			headers.push(header.clone());
+			parent = header;
+		}
+
+		let last_header = headers.last().unwrap().clone();
+		let last_authority = validator(1);
+
+		// Need to make sure that the header we're going to import hasn't been inserted
+		// into storage already
+		let header = HeaderBuilder::with_parent(&last_header).sign_by(&last_authority);
+	}: import_unsigned_header(RawOrigin::None, header, None)
+	verify {
+		let storage = BridgeStorage::<T>::new();
+		assert_eq!(storage.best_block().0.number, (num_blocks + 1) as u64);
+		assert_eq!(storage.finalized_block().number, num_blocks as u64);
+	}
+
+	// Basically the exact same as `import_unsigned_finality` but with a different range for the
+	// complexity parameter. In this bench we use a larger range of blocks to see how performance
+	// changes when the finality cache kicks in (>16 blocks).
+	import_unsigned_finality_with_cache {
+		// Our complexity parameter, n, will represent the number of blocks imported before
+		// finalization.
+		let n in 7..100;
+
+		let mut storage = BridgeStorage::<T>::new();
+		let num_validators: u32 = 2;
+		let initial_header = initialize_bench::<T>(num_validators as usize);
+
+		// Since we only have two validators we need to make sure the number of blocks is even to
+		// make sure the right validator signs the final block
+		let num_blocks = 2 * n;
+		let mut headers = Vec::new();
+		let mut parent = initial_header.clone();
+
+		// Import a bunch of headers without any verification, will ensure that they're not
+		// finalized prematurely
+		for i in 1..=num_blocks {
+			let header = HeaderBuilder::with_parent(&parent).sign_by(&validator(0));
+			let id = header.compute_id();
+			insert_header(&mut storage, header.clone());
+			headers.push(header.clone());
+			parent = header;
+		}
+
+		let last_header = headers.last().unwrap().clone();
+		let last_authority = validator(1);
+
+		// Need to make sure that the header we're going to import hasn't been inserted
+		// into storage already
+		let header = HeaderBuilder::with_parent(&last_header).sign_by(&last_authority);
+	}: import_unsigned_header(RawOrigin::None, header, None)
+	verify {
+		let storage = BridgeStorage::<T>::new();
+		assert_eq!(storage.best_block().0.number, (num_blocks + 1) as u64);
+		assert_eq!(storage.finalized_block().number, num_blocks as u64);
+	}
+
+	// A block import may trigger a pruning event, which adds extra work to the import progress.
+	// In this bench we trigger a pruning event in order to see how much extra time is spent by the
+	// runtime dealing with it. In the Ethereum Pallet, we're limited pruning to eight blocks in a
+	// single import, as dictated by MAX_BLOCKS_TO_PRUNE_IN_SINGLE_IMPORT.
+	import_unsigned_pruning {
+		let n in 1..MAX_BLOCKS_TO_PRUNE_IN_SINGLE_IMPORT as u32;
+
+		let mut storage = BridgeStorage::<T>::new();
+
+		let num_validators = 3;
+		let initial_header = initialize_bench::<T>(num_validators as usize);
+		let validators = validators(num_validators);
+
+		// Want to prune eligible blocks between [0, n)
+		BlocksToPrune::put(PruningRange {
+			oldest_unpruned_block: 0,
+			oldest_block_to_keep: n as u64,
+		});
+
+		let mut parent = initial_header;
+		for i in 1..=n {
+			let header = HeaderBuilder::with_parent(&parent).sign_by_set(&validators);
+			let id = header.compute_id();
+			insert_header(&mut storage, header.clone());
+			parent = header;
+		}
+
+		let header = HeaderBuilder::with_parent(&parent).sign_by_set(&validators);
+	}: import_unsigned_header(RawOrigin::None, header, None)
+	verify {
+		let storage = BridgeStorage::<T>::new();
+		let max_pruned: u64 = (n - 1) as _;
+		assert_eq!(storage.best_block().0.number, (n + 1) as u64);
+		assert!(HeadersByNumber::get(&0).is_none());
+		assert!(HeadersByNumber::get(&max_pruned).is_none());
+	}
+
+	// The goal of this bench is to import a block which contains a transaction receipt. The receipt
+	// will contain a validator set change. Verifying the receipt root is an expensive operation to
+	// do, which is why we're interested in benchmarking it.
+	import_unsigned_with_receipts {
+		let n in 1..100;
+
+		let mut storage = BridgeStorage::<T>::new();
+
+		let num_validators = 1;
+		let initial_header = initialize_bench::<T>(num_validators as usize);
+
+		let mut receipts = vec![];
+		for i in 1..=n {
+			let receipt = validators_change_receipt(Default::default());
+			receipts.push(receipt)
+		}
+		let encoded_receipts = receipts.iter().map(|r| r.rlp());
+
+		// We need this extra header since this is what signals a validator set transition. This
+		// will ensure that the next header is within the "Contract" window
+		let header1 = HeaderBuilder::with_parent(&initial_header).sign_by(&validator(0));
+		insert_header(&mut storage, header1.clone());
+
+		let header = build_custom_header(
+			&validator(0),
+			&header1,
+			|mut header| {
+				// Logs Bloom signals a change in validator set
+				header.log_bloom = (&[0xff; 256]).into();
+				header.receipts_root = compute_merkle_root(encoded_receipts);
+				header
+			},
+		);
+	}: import_unsigned_header(RawOrigin::None, header, Some(receipts))
+	verify {
+		let storage = BridgeStorage::<T>::new();
+		assert_eq!(storage.best_block().0.number, 2);
+	}
+}
+
+fn initialize_bench<T: Trait>(num_validators: usize) -> Header {
+	// Initialize storage with some initial header
+	let initial_header = build_genesis_header(&validator(0));
+	let initial_difficulty = initial_header.difficulty;
+	let initial_validators = validators_addresses(num_validators as usize);
+
+	initialize_storage::<T>(&initial_header, initial_difficulty, &initial_validators);
+
+	initial_header
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use crate::mock::{run_test, TestRuntime};
+	use frame_support::assert_ok;
+
+	#[test]
+	fn insert_unsigned_header_best_case() {
+		run_test(1, |_| {
+			assert_ok!(test_benchmark_import_unsigned_header_best_case::<TestRuntime>());
+		});
+	}
+
+	#[test]
+	fn insert_unsigned_header_finality() {
+		run_test(1, |_| {
+			assert_ok!(test_benchmark_import_unsigned_finality::<TestRuntime>());
+		});
+	}
+
+	#[test]
+	fn insert_unsigned_header_finality_with_cache() {
+		run_test(1, |_| {
+			assert_ok!(test_benchmark_import_unsigned_finality_with_cache::<TestRuntime>());
+		});
+	}
+
+	#[test]
+	fn insert_unsigned_header_pruning() {
+		run_test(1, |_| {
+			assert_ok!(test_benchmark_import_unsigned_pruning::<TestRuntime>());
+		});
+	}
+
+	#[test]
+	fn insert_unsigned_header_receipts() {
+		run_test(1, |_| {
+			assert_ok!(test_benchmark_import_unsigned_with_receipts::<TestRuntime>());
+		});
 	}
 }

modules/ethereum/src/import.rs

@@ -163,7 +163,7 @@ mod tests {
 	use super::*;
 	use crate::mock::{
 		run_test, secret_to_address, test_aura_config, test_validators_config, validator, validators_addresses,
-		HeaderBuilder, KeepSomeHeadersBehindBest, TestRuntime, GAS_LIMIT,
+		validators_change_receipt, HeaderBuilder, KeepSomeHeadersBehindBest, TestRuntime, GAS_LIMIT,
 	};
 	use crate::validators::ValidatorsSource;
 	use crate::{BlocksToPrune, BridgeStorage, Headers, PruningRange};
@@ -316,9 +316,7 @@ mod tests {
 				&validators_config,
 				Some(101),
 				header11.clone(),
-				Some(vec![crate::validators::tests::validators_change_recept(
-					latest_block_id.hash,
-				)]),
+				Some(vec![validators_change_receipt(latest_block_id.hash)]),
 			)
 			.unwrap();
 			assert_eq!(finalized_blocks, vec![(parent_id, Some(100))],);

modules/ethereum/src/lib.rs

@@ -463,7 +463,7 @@ decl_storage! {
 			// the initial blocks should be selected so that:
 			// 1) it doesn't signal validators changes;
 			// 2) there are no scheduled validators changes from previous blocks;
-			// 3) (implied) all direct children of initial block are authred by the same validators set.
+			// 3) (implied) all direct children of initial block are authored by the same validators set.
 
 			assert!(
 				!config.initial_validators.is_empty(),
@@ -563,6 +563,7 @@ impl<T: Trait> BridgeStorage<T> {
 		// start pruning blocks
 		let begin = new_pruning_range.oldest_unpruned_block;
 		let end = new_pruning_range.oldest_block_to_keep;
+		frame_support::debug::trace!(target: "runtime", "Pruning blocks in range [{}..{})", begin, end);
 		for number in begin..end {
 			// if we can't prune anything => break
 			if max_blocks_to_prune == 0 {
@@ -588,6 +589,11 @@ impl<T: Trait> BridgeStorage<T> {
 
 			// we have pruned all headers at number
 			new_pruning_range.oldest_unpruned_block = number + 1;
+			frame_support::debug::trace!(
+				target: "runtime",
+				"Oldest unpruned PoA header is now: {}",
+				new_pruning_range.oldest_unpruned_block,
+			);
 		}
 
 		// update pruning range in storage

modules/ethereum/src/mock.rs

@@ -14,12 +14,11 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
 
-pub use crate::test_utils::{validator_utils::*, HeaderBuilder, GAS_LIMIT};
+pub use crate::test_utils::{insert_header, validator_utils::*, validators_change_receipt, HeaderBuilder, GAS_LIMIT};
 pub use primitives::signatures::secret_to_address;
 
-use crate::finality::FinalityVotes;
 use crate::validators::{ValidatorsConfiguration, ValidatorsSource};
-use crate::{AuraConfiguration, GenesisConfig, HeaderToImport, PruningStrategy, Storage, Trait};
+use crate::{AuraConfiguration, GenesisConfig, PruningStrategy, Trait};
 use frame_support::{impl_outer_origin, parameter_types, weights::Weight};
 use primitives::{Address, Header, H256, U256};
 use secp256k1::SecretKey;
@@ -149,20 +148,6 @@ pub fn run_test_with_genesis<T>(genesis: Header, total_validators: usize, test:
 	})
 }
 
-/// Insert unverified header into storage.
-pub fn insert_header<S: Storage>(storage: &mut S, header: Header) {
-	storage.insert_header(HeaderToImport {
-		context: storage.import_context(None, &header.parent_hash).unwrap(),
-		is_best: true,
-		id: header.compute_id(),
-		header,
-		total_difficulty: 0.into(),
-		enacted_change: None,
-		scheduled_change: None,
-		finality_votes: FinalityVotes::default(),
-	});
-}
-
 /// Pruning strategy that keeps 10 headers behind best block.
 pub struct KeepSomeHeadersBehindBest(pub u64);