fix(sequencer): fix checkpoint budget redistribution for multi-block slots

yarn-project/sequencer-client/src/client/sequencer-client.ts

@@ -19,15 +19,10 @@ import type { L1ToL2MessageSource } from '@aztec/stdlib/messaging';
 import { L1Metrics, type TelemetryClient } from '@aztec/telemetry-client';
 import { FullNodeCheckpointsBuilder, NodeKeystoreAdapter, type ValidatorClient } from '@aztec/validator-client';
 
-import {
-  DefaultSequencerConfig,
-  type SequencerClientConfig,
-  getPublisherConfigFromSequencerConfig,
-} from '../config.js';
+import { type SequencerClientConfig, getPublisherConfigFromSequencerConfig } from '../config.js';
 import { GlobalVariableBuilder } from '../global_variable_builder/index.js';
 import { SequencerPublisherFactory } from '../publisher/sequencer-publisher-factory.js';
 import { Sequencer, type SequencerConfig } from '../sequencer/index.js';
-import { SequencerTimetable } from '../sequencer/timetable.js';
 
 /**
  * Encapsulates the full sequencer and publisher.
@@ -160,12 +155,7 @@ export class SequencerClient {
     const l1PublishingTimeBasedOnChain = isAnvilTestChain(config.l1ChainId) ? 1 : ethereumSlotDuration;
     const l1PublishingTime = config.l1PublishingTime ?? l1PublishingTimeBasedOnChain;
 
-    const { maxL2BlockGas, maxDABlockGas, maxTxsPerBlock, maxBlocksPerCheckpoint } = computeBlockLimits(
-      config,
-      rollupManaLimit,
-      l1PublishingTime,
-      log,
-    );
+    const { maxL2BlockGas, maxDABlockGas, maxTxsPerBlock } = capPerBlockLimits(config, rollupManaLimit, log);
 
     const l1Constants = { l1GenesisTime, slotDuration: Number(slotDuration), ethereumSlotDuration, rollupManaLimit };
 
@@ -183,7 +173,7 @@ export class SequencerClient {
       deps.dateProvider,
       epochCache,
       rollupContract,
-      { ...config, l1PublishingTime, maxL2BlockGas, maxDABlockGas, maxTxsPerBlock, maxBlocksPerCheckpoint },
+      { ...config, l1PublishingTime, maxL2BlockGas, maxDABlockGas, maxTxsPerBlock },
       telemetryClient,
       log,
     );
@@ -248,88 +238,39 @@ export class SequencerClient {
 }
 
 /**
- * Computes per-block L2 gas, DA gas, and TX count budgets based on the L1 rollup limits and the timetable.
- * If the user explicitly set a limit, it is capped at the corresponding checkpoint limit.
- * Otherwise, derives it as (checkpointLimit / maxBlocks) * multiplier, capped at the checkpoint limit.
+ * Caps operator-provided per-block limits at checkpoint-level limits.
+ * Returns undefined for any limit the operator didn't set — the checkpoint builder handles redistribution.
  */
-export function computeBlockLimits(
+function capPerBlockLimits(
   config: SequencerClientConfig,
   rollupManaLimit: number,
-  l1PublishingTime: number,
   log: ReturnType<typeof createLogger>,
-): { maxL2BlockGas: number; maxDABlockGas: number; maxTxsPerBlock: number; maxBlocksPerCheckpoint: number } {
-  const maxNumberOfBlocks = new SequencerTimetable({
-    ethereumSlotDuration: config.ethereumSlotDuration,
-    aztecSlotDuration: config.aztecSlotDuration,
-    l1PublishingTime,
-    p2pPropagationTime: config.attestationPropagationTime,
-    blockDurationMs: config.blockDurationMs,
-    enforce: config.enforceTimeTable ?? DefaultSequencerConfig.enforceTimeTable,
-  }).maxNumberOfBlocks;
-
-  const multiplier = config.perBlockAllocationMultiplier ?? DefaultSequencerConfig.perBlockAllocationMultiplier;
-
-  // Compute maxL2BlockGas
-  let maxL2BlockGas: number;
-  if (config.maxL2BlockGas !== undefined) {
-    if (config.maxL2BlockGas > rollupManaLimit) {
-      log.warn(
-        `Provided MAX_L2_BLOCK_GAS ${config.maxL2BlockGas} exceeds L1 rollup mana limit ${rollupManaLimit} (capping)`,
-      );
-      maxL2BlockGas = rollupManaLimit;
-    } else {
-      maxL2BlockGas = config.maxL2BlockGas;
-    }
-  } else {
-    maxL2BlockGas = Math.min(rollupManaLimit, Math.ceil((rollupManaLimit / maxNumberOfBlocks) * multiplier));
+): { maxL2BlockGas: number | undefined; maxDABlockGas: number | undefined; maxTxsPerBlock: number | undefined } {
+  let maxL2BlockGas = config.maxL2BlockGas;
+  if (maxL2BlockGas !== undefined && maxL2BlockGas > rollupManaLimit) {
+    log.warn(`Provided MAX_L2_BLOCK_GAS ${maxL2BlockGas} exceeds rollup mana limit ${rollupManaLimit} (capping)`);
+    maxL2BlockGas = rollupManaLimit;
   }
 
-  // Compute maxDABlockGas
-  const daCheckpointLimit = MAX_PROCESSABLE_DA_GAS_PER_CHECKPOINT;
-  let maxDABlockGas: number;
-  if (config.maxDABlockGas !== undefined) {
-    if (config.maxDABlockGas > daCheckpointLimit) {
-      log.warn(
-        `Provided MAX_DA_BLOCK_GAS ${config.maxDABlockGas} exceeds DA checkpoint limit ${daCheckpointLimit} (capping)`,
-      );
-      maxDABlockGas = daCheckpointLimit;
-    } else {
-      maxDABlockGas = config.maxDABlockGas;
-    }
-  } else {
-    maxDABlockGas = Math.min(daCheckpointLimit, Math.ceil((daCheckpointLimit / maxNumberOfBlocks) * multiplier));
+  let maxDABlockGas = config.maxDABlockGas;
+  if (maxDABlockGas !== undefined && maxDABlockGas > MAX_PROCESSABLE_DA_GAS_PER_CHECKPOINT) {
+    log.warn(
+      `Provided MAX_DA_BLOCK_GAS ${maxDABlockGas} exceeds DA checkpoint limit ${MAX_PROCESSABLE_DA_GAS_PER_CHECKPOINT} (capping)`,
+    );
+    maxDABlockGas = MAX_PROCESSABLE_DA_GAS_PER_CHECKPOINT;
   }
 
-  // Compute maxTxsPerBlock
-  const defaultMaxTxsPerBlock = 32;
-  let maxTxsPerBlock: number;
-  if (config.maxTxsPerBlock !== undefined) {
-    if (config.maxTxsPerCheckpoint !== undefined && config.maxTxsPerBlock > config.maxTxsPerCheckpoint) {
-      log.warn(
-        `Provided MAX_TX_PER_BLOCK ${config.maxTxsPerBlock} exceeds MAX_TX_PER_CHECKPOINT ${config.maxTxsPerCheckpoint} (capping)`,
-      );
-      maxTxsPerBlock = config.maxTxsPerCheckpoint;
-    } else {
-      maxTxsPerBlock = config.maxTxsPerBlock;
-    }
-  } else if (config.maxTxsPerCheckpoint !== undefined) {
-    maxTxsPerBlock = Math.min(
-      config.maxTxsPerCheckpoint,
-      Math.ceil((config.maxTxsPerCheckpoint / maxNumberOfBlocks) * multiplier),
+  let maxTxsPerBlock = config.maxTxsPerBlock;
+  if (
+    maxTxsPerBlock !== undefined &&
+    config.maxTxsPerCheckpoint !== undefined &&
+    maxTxsPerBlock > config.maxTxsPerCheckpoint
+  ) {
+    log.warn(
+      `Provided MAX_TX_PER_BLOCK ${maxTxsPerBlock} exceeds MAX_TX_PER_CHECKPOINT ${config.maxTxsPerCheckpoint} (capping)`,
     );
-  } else {
-    maxTxsPerBlock = defaultMaxTxsPerBlock;
+    maxTxsPerBlock = config.maxTxsPerCheckpoint;
   }
 
-  log.info(`Computed block limits L2=${maxL2BlockGas} DA=${maxDABlockGas} maxTxs=${maxTxsPerBlock}`, {
-    maxL2BlockGas,
-    maxDABlockGas,
-    maxTxsPerBlock,
-    rollupManaLimit,
-    daCheckpointLimit,
-    maxNumberOfBlocks,
-    multiplier,
-  });
-
-  return { maxL2BlockGas, maxDABlockGas, maxTxsPerBlock, maxBlocksPerCheckpoint: maxNumberOfBlocks };
+  return { maxL2BlockGas, maxDABlockGas, maxTxsPerBlock };
 }

yarn-project/sequencer-client/src/config.ts

@@ -119,9 +119,6 @@ export const sequencerConfigMappings: ConfigMappingsType<SequencerConfig> = {
       'Redistribute remaining checkpoint budget evenly across remaining blocks instead of allowing a single block to consume the entire remaining budget.',
     ...booleanConfigHelper(DefaultSequencerConfig.redistributeCheckpointBudget),
   },
-  maxBlocksPerCheckpoint: {
-    description: 'Computed max number of blocks per checkpoint from timetable.',
-  },
   coinbase: {
     env: 'COINBASE',
     parseEnv: (val: string) => (val ? EthAddress.fromString(val) : undefined),

yarn-project/sequencer-client/src/sequencer/checkpoint_proposal_job.timing.test.ts

@@ -14,8 +14,8 @@ import type { L2Block, L2BlockSink, L2BlockSource } from '@aztec/stdlib/block';
 import type { L1RollupConstants } from '@aztec/stdlib/epoch-helpers';
 import { GasFees } from '@aztec/stdlib/gas';
 import type {
+  BlockBuilderOptions,
   MerkleTreeWriteOperations,
-  PublicProcessorLimits,
   ResolvedSequencerConfig,
   WorldStateSynchronizer,
 } from '@aztec/stdlib/interfaces/server';
@@ -80,7 +80,7 @@ class TimingAwareMockCheckpointBuilder extends MockCheckpointBuilder {
     pendingTxs: Iterable<Tx> | AsyncIterable<Tx>,
     blockNumber: BlockNumber,
     timestamp: bigint,
-    opts: PublicProcessorLimits,
+    opts: BlockBuilderOptions,
   ): Promise<BuildBlockInCheckpointResult> {
     const startTime = this.getSecondsIntoSlot();
 

yarn-project/sequencer-client/src/sequencer/checkpoint_proposal_job.ts

@@ -34,8 +34,8 @@ import { type Checkpoint, validateCheckpoint } from '@aztec/stdlib/checkpoint';
 import { getSlotStartBuildTimestamp } from '@aztec/stdlib/epoch-helpers';
 import { Gas } from '@aztec/stdlib/gas';
 import {
+  type BlockBuilderOptions,
   InsufficientValidTxsError,
-  type PublicProcessorLimits,
   type ResolvedSequencerConfig,
   type WorldStateSynchronizer,
 } from '@aztec/stdlib/interfaces/server';
@@ -270,7 +270,8 @@ export class CheckpointProposalJob implements Traceable {
       this.setStateFn(SequencerState.ASSEMBLING_CHECKPOINT, this.slot);
       const checkpoint = await checkpointBuilder.completeCheckpoint();
 
-      // Final validation round for the checkpoint before we propose it, just for safety
+      // Final validation: per-block limits are only checked if the operator set them explicitly.
+      // Otherwise, checkpoint-level budgets were already enforced by the redistribution logic.
       try {
         validateCheckpoint(checkpoint, {
           rollupManaLimit: this.l1Constants.rollupManaLimit,
@@ -574,11 +575,11 @@ export class CheckpointProposalJob implements Traceable {
       );
       this.setStateFn(SequencerState.CREATING_BLOCK, this.slot);
 
-      // Per-block limits derived at startup by computeBlockLimits(), further capped
+      // Per-block limits are operator overrides (from SEQ_MAX_L2_BLOCK_GAS etc.) further capped
       // by remaining checkpoint-level budgets inside CheckpointBuilder before each block is built.
       // minValidTxs is passed into the builder so it can reject the block *before* updating state.
       const minValidTxs = forceCreate ? 0 : (this.config.minValidTxsPerBlock ?? minTxs);
-      const blockBuilderOptions: PublicProcessorLimits & { minValidTxs?: number } = {
+      const blockBuilderOptions: BlockBuilderOptions = {
         maxTransactions: this.config.maxTxsPerBlock,
         maxBlockGas:
           this.config.maxL2BlockGas !== undefined || this.config.maxDABlockGas !== undefined
@@ -587,6 +588,8 @@ export class CheckpointProposalJob implements Traceable {
         deadline: buildDeadline,
         isBuildingProposal: true,
         minValidTxs,
+        maxBlocksPerCheckpoint: this.timetable.maxNumberOfBlocks,
+        perBlockAllocationMultiplier: this.config.perBlockAllocationMultiplier,
       };
 
       // Actually build the block by executing txs. The builder throws InsufficientValidTxsError
@@ -657,7 +660,7 @@ export class CheckpointProposalJob implements Traceable {
     pendingTxs: AsyncIterable<Tx>,
     blockNumber: BlockNumber,
     blockTimestamp: bigint,
-    blockBuilderOptions: PublicProcessorLimits & { minValidTxs?: number },
+    blockBuilderOptions: BlockBuilderOptions,
   ) {
     try {
       const workTimer = new Timer();

yarn-project/sequencer-client/src/test/mock_checkpoint_builder.ts

@@ -4,11 +4,11 @@ import { unfreeze } from '@aztec/foundation/types';
 import { L2Block } from '@aztec/stdlib/block';
 import { Checkpoint } from '@aztec/stdlib/checkpoint';
 import type {
+  BlockBuilderOptions,
   FullNodeBlockBuilderConfig,
   ICheckpointBlockBuilder,
   ICheckpointsBuilder,
   MerkleTreeWriteOperations,
-  PublicProcessorLimits,
 } from '@aztec/stdlib/interfaces/server';
 import { CheckpointHeader } from '@aztec/stdlib/rollup';
 import { makeAppendOnlyTreeSnapshot } from '@aztec/stdlib/testing';
@@ -32,7 +32,7 @@ export class MockCheckpointBuilder implements ICheckpointBlockBuilder {
   public buildBlockCalls: Array<{
     blockNumber: BlockNumber;
     timestamp: bigint;
-    opts: PublicProcessorLimits & { minValidTxs?: number };
+    opts: BlockBuilderOptions;
   }> = [];
   /** Track all consumed transaction hashes across buildBlock calls */
   public consumedTxHashes: Set<string> = new Set();
@@ -74,7 +74,7 @@ export class MockCheckpointBuilder implements ICheckpointBlockBuilder {
     pendingTxs: Iterable<Tx> | AsyncIterable<Tx>,
     blockNumber: BlockNumber,
     timestamp: bigint,
-    opts: PublicProcessorLimits & { minValidTxs?: number },
+    opts: BlockBuilderOptions,
   ): Promise<BuildBlockInCheckpointResult> {
     this.buildBlockCalls.push({ blockNumber, timestamp, opts });
 

yarn-project/slasher/src/watchers/epoch_prune_watcher.test.ts

@@ -186,7 +186,7 @@ describe('EpochPruneWatcher', () => {
       [tx],
       block.header.globalVariables.blockNumber,
       block.header.globalVariables.timestamp,
-      {},
+      { isBuildingProposal: false, minValidTxs: 0 },
     );
   });
 
@@ -246,7 +246,7 @@ describe('EpochPruneWatcher', () => {
       [tx],
       blockFromL1.header.globalVariables.blockNumber,
       blockFromL1.header.globalVariables.timestamp,
-      {},
+      { isBuildingProposal: false, minValidTxs: 0 },
     );
   });
 });