Create Benchmarking Setup for Identity Pallet #4695 (#4818)

* Starting

* closer

* Compiles!

* comments

* Create seperate mock

* Remove changes to test env

* Fix step calculation

* Add host function

* Add runtime api

* compiles

* Update to use offchain timestamp

* Gives a result

* added some CLI wip

* make generic

* Update instance

* Remove CLI stuff

* Remove last cli stuff

* undo more changes

* Update benchmarks

* Update Cargo.lock

* remove test

* Move loop out of runtime

* Benchmarking externalities

* Benchmarking state

* Implemented commit

* Make CLI work, move loop back into runtime

* Wipe resets to genesis

* Speedup benchmarks

* Use enum to select extrinsic within pallet

* CLI controls which module and extrinsic to call

* Select a pallet with cli

* Add steps and repeats to cli

* Output as CSV format

* Introduce benchmark pallet

* Append bench

* Use Results

* fix merge

* Clear Identity benchmark

* Bench request judgment and cancel request

* Add final benchmarks

* Fix CSV output

* Start cleaning up for PR

* Bump numbers in `wasmtime` integration tests.

* More docs

* Add rockdb feature to bench

* Fix formatting issues

* Add test feature to bench

* Add test feature to bench

* Add rocksdb feature flag

* Update bench.rs

Co-authored-by: Arkadiy Paronyan <arkady.paronyan@gmail.com>
Co-authored-by: Gavin Wood <github@gavwood.com>

substrate/primitives/state-machine/src/overlayed_changes.rs

@@ -428,15 +428,18 @@ impl OverlayedChanges {
 	///
 	/// Panics:
 	/// Will panic if there are any uncommitted prospective changes.
-	pub fn into_committed(self) -> (
+	fn drain_committed(&mut self) -> (
 		impl Iterator<Item=(StorageKey, Option<StorageValue>)>,
 		impl Iterator<Item=(StorageKey, (impl Iterator<Item=(StorageKey, Option<StorageValue>)>, OwnedChildInfo))>,
-	){
+	) {
 		assert!(self.prospective.is_empty());
 		(
-			self.committed.top.into_iter().map(|(k, v)| (k, v.value)),
-			self.committed.children.into_iter()
-				.map(|(sk, (v, ci))| (sk, (v.into_iter().map(|(k, v)| (k, v.value)), ci)))
+			std::mem::replace(&mut self.committed.top, Default::default())
+				.into_iter()
+				.map(|(k, v)| (k, v.value)),
+			std::mem::replace(&mut self.committed.children, Default::default())
+				.into_iter()
+				.map(|(sk, (v, ci))| (sk, (v.into_iter().map(|(k, v)| (k, v.value)), ci))),
 		)
 	}
 
@@ -444,11 +447,22 @@ impl OverlayedChanges {
 	pub fn into_storage_changes<
 		B: Backend<H>, H: Hasher, N: BlockNumber
 	>(
-		self,
+		mut self,
 		backend: &B,
 		changes_trie_state: Option<&ChangesTrieState<H, N>>,
 		parent_hash: H::Out,
 		mut cache: StorageTransactionCache<B::Transaction, H, N>,
+	) -> Result<StorageChanges<B::Transaction, H, N>, String> where H::Out: Ord + Encode + 'static {
+		self.drain_storage_changes(backend, changes_trie_state, parent_hash, &mut cache)
+	}
+
+	/// Drain all changes into a [`StorageChanges`] instance. Leave empty overlay in place.
+	pub fn drain_storage_changes<B: Backend<H>, H: Hasher, N: BlockNumber>(
+		&mut self,
+		backend: &B,
+		changes_trie_state: Option<&ChangesTrieState<H, N>>,
+		parent_hash: H::Out,
+		mut cache: &mut StorageTransactionCache<B::Transaction, H, N>,
 	) -> Result<StorageChanges<B::Transaction, H, N>, String> where H::Out: Ord + Encode + 'static {
 		// If the transaction does not exist, we generate it.
 		if cache.transaction.is_none() {
@@ -474,7 +488,7 @@ impl OverlayedChanges {
 			.take()
 			.expect("Changes trie transaction was generated by `changes_trie_root`; qed");
 
-		let (main_storage_changes, child_storage_changes) = self.into_committed();
+		let (main_storage_changes, child_storage_changes) = self.drain_committed();
 
 		Ok(StorageChanges {
 			main_storage_changes: main_storage_changes.collect(),