perf!: Make slashing not write sign info every block (SDK: cosmos#19458

)

cosmos#19458

CHANGELOG.md

@@ -37,6 +37,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ## [Unreleased]
 
+* (slashing) [#19458](https://github.com/cosmos/cosmos-sdk/pull/19458) Avoid writing SignInfo's for validator's who did not miss a block. (Every BeginBlock)
 * (slashing) [#18959](https://github.com/cosmos/cosmos-sdk/pull/18959) Slight speedup to Slashing Beginblock logic
 
 ## [v0.47.5](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.47.5) - 2023-09-01

proto/cosmos/slashing/v1beta1/slashing.proto

@@ -19,10 +19,10 @@ message ValidatorSigningInfo {
   string address = 1 [(cosmos_proto.scalar) = "cosmos.AddressString"];
   // Height at which validator was first a candidate OR was unjailed
   int64 start_height = 2;
-  // Index which is incremented each time the validator was a bonded
-  // in a block and may have signed a precommit or not. This in conjunction with the
-  // `SignedBlocksWindow` param determines the index in the `MissedBlocksBitArray`.
-  int64 index_offset = 3;
+  // DEPRECATED: Index which is incremented every time a validator is bonded in a block and
+  // _may_ have signed a pre-commit or not. This in conjunction with the
+  // signed_blocks_window param determines the index in the missed block bitmap.
+  int64 index_offset = 3 [deprecated = true];
   // Timestamp until which the validator is jailed due to liveness downtime.
   google.protobuf.Timestamp jailed_until = 4
       [(gogoproto.stdtime) = true, (gogoproto.nullable) = false, (amino.dont_omitempty) = true];

x/slashing/README.md

@@ -212,8 +212,8 @@ provisions and rewards.
 At the beginning of each block, we update the `ValidatorSigningInfo` for each
 validator and check if they've crossed below the liveness threshold over a
 sliding window. This sliding window is defined by `SignedBlocksWindow` and the
-index in this window is determined by `IndexOffset` found in the validator's
-`ValidatorSigningInfo`. For each block processed, the `IndexOffset` is incremented
+index in this window is determined by (`IndexOffset = height - SignInfo.StartHeight`).
+Note that in each block processed, the `IndexOffset` is incremented
 regardless if the validator signed or not. Once the index is determined, the
 `MissedBlocksBitArray` and `MissedBlocksCounter` are updated accordingly.
 
@@ -235,10 +235,8 @@ for vote in block.LastCommitInfo.Votes {
   signInfo := GetValidatorSigningInfo(vote.Validator.Address)
 
   // This is a relative index, so we counts blocks the validator SHOULD have
-  // signed. We use the 0-value default signing info if not present, except for
-  // start height.
-  index := signInfo.IndexOffset % SignedBlocksWindow()
-  signInfo.IndexOffset++
+  // signed. We use the 0-value default signing info if not present.
+  index := (height - signInfo.StartHeight) % SignedBlocksWindow()
 
   // Update MissedBlocksBitArray and MissedBlocksCounter. The MissedBlocksCounter
   // just tracks the sum of MissedBlocksBitArray. That way we avoid needing to

x/slashing/keeper/infractions.go

@@ -36,24 +36,35 @@ func (k Keeper) HandleValidatorSignatureWithParams(ctx sdk.Context, params types
 	signedBlocksWindow := params.SignedBlocksWindow
 
 	// Compute the relative index, so we count the blocks the validator *should*
-	// have signed. We will use the 0-value default signing info if not present,
-	// except for start height. The index is in the range [0, SignedBlocksWindow)
+	// have signed. We will also use the 0-value default signing info if not present.
+	// The index is in the range [0, SignedBlocksWindow)
 	// and is used to see if a validator signed a block at the given height, which
 	// is represented by a bit in the bitmap.
-	index := signInfo.IndexOffset % signedBlocksWindow
-	signInfo.IndexOffset++
-
+	// The validator start height should get mapped to index 0, so we computed index as:
+	// (height - startHeight) % signedBlocksWindow
+	//
+	// NOTE: There is subtle different behavior between genesis validators and non-genesis validators.
+	// A genesis validator will start at index 0, whereas a non-genesis validator's startHeight will be the block
+	// they bonded on, but the first block they vote on will be one later. (And thus their first vote is at index 1)
+	index := (height - signInfo.StartHeight) % signedBlocksWindow
+	if signInfo.StartHeight > height {
+		panic(fmt.Errorf("invalid state, the validator %v has start height %d , which is greater than the current height %d (as parsed from the header)",
+			signInfo.Address, signInfo.StartHeight, height))
+	}
 	// Update signed block bit array & counter
 	// This counter just tracks the sum of the bit array
 	// That way we avoid needing to read/write the whole array each time
 	previous := k.GetValidatorMissedBlockBitArray(ctx, consAddr, index)
+	modifiedSignInfo := false
 	missed := !signed
 	switch {
 	case !previous && missed:
+		modifiedSignInfo = true
 		// Array value has changed from not missed to missed, increment counter
 		k.SetValidatorMissedBlockBitArray(ctx, consAddr, index, true)
 		signInfo.MissedBlocksCounter++
 	case previous && !missed:
+		modifiedSignInfo = true
 		// Array value has changed from missed to not missed, decrement counter
 		k.SetValidatorMissedBlockBitArray(ctx, consAddr, index, false)
 		signInfo.MissedBlocksCounter--
@@ -87,6 +98,7 @@ func (k Keeper) HandleValidatorSignatureWithParams(ctx sdk.Context, params types
 
 	// if we are past the minimum height and the validator has missed too many blocks, punish them
 	if height > minHeight && signInfo.MissedBlocksCounter > maxMissed {
+		modifiedSignInfo = true
 		validator := k.sk.ValidatorByConsAddr(ctx, consAddr)
 		if validator != nil && !validator.IsJailed() {
 			// Downtime confirmed: slash and jail the validator
@@ -113,8 +125,9 @@ func (k Keeper) HandleValidatorSignatureWithParams(ctx sdk.Context, params types
 			signInfo.JailedUntil = ctx.BlockHeader().Time.Add(k.DowntimeJailDuration(ctx))
 
 			// We need to reset the counter & array so that the validator won't be immediately slashed for downtime upon rebonding.
+			// We don't set the start height as this will get correctly set
+			// once they bond again in the AfterValidatorBonded hook!
 			signInfo.MissedBlocksCounter = 0
-			signInfo.IndexOffset = 0
 			k.clearValidatorMissedBlockBitArray(ctx, consAddr)
 
 			logger.Info(
@@ -136,5 +149,7 @@ func (k Keeper) HandleValidatorSignatureWithParams(ctx sdk.Context, params types
 	}
 
 	// Set the updated signing info
-	k.SetValidatorSigningInfo(ctx, consAddr, signInfo)
+	if modifiedSignInfo {
+		k.SetValidatorSigningInfo(ctx, consAddr, signInfo)
+	}
 }