perf(consensus): add simplistic block validation cache (cometbft#3070)

sergio-mena · andynog · ValarDragon · commit 2dd4e034f04e · 2024-05-25T11:05:04.000+09:00
Closes cometbft#2854 Follow up from cometbft#2960 This PR adds a simplistic 1-element block validation cache in `BlockExecutor`. This addresses a performance bottleneck raised as part of cometbft#2854 --- - [ ] Tests written/updated - [ ] Changelog entry added in `.changelog` (we use [unclog](https://github.com/informalsystems/unclog) to manage our changelog) - [ ] Updated relevant documentation (`docs/` or `spec/`) and code comments - [ ] Title follows the [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/) spec --------- Co-authored-by: Andy Nogueira <me@andynogueira.dev>
diff --git a/state/execution.go b/state/execution.go
@@ -36,6 +36,9 @@ type BlockExecutor struct {
 	mempool mempool.Mempool
 	evpool  EvidencePool
 
+	// 1-element cache of validated blocks
+	lastValidatedBlock *types.Block
+
 	logger log.Logger
 
 	metrics *Metrics
@@ -172,9 +175,11 @@ func (blockExec *BlockExecutor) ProcessProposal(
 // Validation does not mutate state, but does require historical information from the stateDB,
 // ie. to verify evidence from a validator at an old height.
 func (blockExec *BlockExecutor) ValidateBlock(state State, block *types.Block) error {
-	err := validateBlock(state, block)
-	if err != nil {
-		return err
+	if !blockExec.lastValidatedBlock.HashesTo(block.Hash()) {
+		if err := validateBlock(state, block); err != nil {
+			return err
+		}
+		blockExec.lastValidatedBlock = block
 	}
 	return blockExec.evpool.CheckEvidence(block.Evidence.Evidence)
 }
@@ -195,11 +200,12 @@ func (blockExec *BlockExecutor) ApplyVerifiedBlock(
 func (blockExec *BlockExecutor) ApplyBlock(
 	state State, blockID types.BlockID, block *types.Block,
 ) (State, int64, error) {
-
-	if err := validateBlock(state, block); err != nil {
-		return state, 0, ErrInvalidBlock(err)
+	if !blockExec.lastValidatedBlock.HashesTo(block.Hash()) {
+		if err := validateBlock(state, block); err != nil {
+			return state, 0, ErrInvalidBlock(err)
+		}
+		blockExec.lastValidatedBlock = block
 	}
-
 	return blockExec.applyBlock(state, blockID, block)
 }
 
