ChainSafe · ensi321 · Sep 26, 2025 · Jul 29, 2025 · Jul 29, 2025 · Jul 29, 2025
@@ -1224,7 +1224,7 @@
           "refId": "A"
         }
       ],
-      "title": "Publish attestation diff from slot 1/3",
+      "title": "Publish attestation diff from slot ATTESTATION_DUE_BPS",
       "tooltip": {
         "show": true,
         "showHistogram": false
@@ -1339,7 +1339,7 @@
           "refId": "A"
         }
       ],
-      "title": "Publish aggregate diff from slot 2/3",
+      "title": "Publish aggregate diff from slot AGGREGATE_DUE_BPS",
       "tooltip": {
         "show": true,
         "showHistogram": false
@@ -1452,7 +1452,7 @@
           "refId": "A"
         }
       ],
-      "title": "Publish sync committee message diff from slot 1/3",
+      "title": "Publish sync committee message diff from slot SYNC_MESSAGE_DUE_BPS",
       "tooltip": {
         "show": true,
         "showHistogram": false
@@ -1565,7 +1565,7 @@
           "refId": "A"
         }
       ],
-      "title": "Publish block diff from slot 0/3",
+      "title": "Publish block diff from start of slot",
       "tooltip": {
         "show": true,
         "showHistogram": false

@@ -66,7 +66,7 @@ import {
   SyncCommitteeErrorCode,
 } from "../../../chain/errors/index.js";
 import {ChainEvent, CheckpointHex, CommonBlockBody} from "../../../chain/index.js";
-import {SCHEDULER_LOOKAHEAD_FACTOR} from "../../../chain/prepareNextSlot.js";
+import {PREPARE_NEXT_SLOT_BPS} from "../../../chain/prepareNextSlot.js";
 import {BlockType, ProduceFullDeneb} from "../../../chain/produceBlock/index.js";
 import {RegenCaller} from "../../../chain/regen/index.js";
 import {validateApiAggregateAndProof} from "../../../chain/validation/index.js";
@@ -108,6 +108,8 @@ export const SYNC_TOLERANCE_EPOCHS = 1;
  * Empirically the builder block resolves in ~1 second, and execution block resolves in <500 ms.
  * A cutoff of 2 seconds gives enough time and if there are unexpected delays it ensures we publish
  * in time as proposals post 4 seconds into the slot will likely be orphaned due to proposer boost reorg.
+ *
+ * TODO GLOAS: re-evaluate cutoff timing
  */
 const BLOCK_PRODUCTION_RACE_CUTOFF_MS = 2_000;
 /** Overall timeout for execution and block production apis */
@@ -666,7 +668,7 @@ export function getValidatorApi(
       : Promise.reject(new Error("Engine disabled"));
 
     // Calculate cutoff time based on start of the slot
-    const cutoffMs = Math.max(0, BLOCK_PRODUCTION_RACE_CUTOFF_MS - Math.round(chain.clock.secFromSlot(slot) * 1000));
+    const cutoffMs = Math.max(0, BLOCK_PRODUCTION_RACE_CUTOFF_MS - chain.clock.msFromSlot(slot));
 
     logger.verbose("Block production race (builder vs execution) starting", {
       ...loggerContext,
@@ -1017,7 +1019,7 @@ export function getValidatorApi(
       let state: CachedBeaconStateAllForks | undefined = undefined;
       const startSlot = computeStartSlotAtEpoch(epoch);
       const slotMs = config.SECONDS_PER_SLOT * 1000;
-      const prepareNextSlotLookAheadMs = slotMs / SCHEDULER_LOOKAHEAD_FACTOR;
+      const prepareNextSlotLookAheadMs = slotMs - config.getSlotComponentDurationMs(PREPARE_NEXT_SLOT_BPS);
       const toNextEpochMs = msToNextEpoch();
       // validators may request next epoch's duties when it's close to next epoch
       // this is to avoid missed block proposal due to 0 epoch look ahead

@@ -7,14 +7,7 @@ import {
   ForkChoiceErrorCode,
   NotReorgedReason,
 } from "@lodestar/fork-choice";
-import {
-  ForkPostAltair,
-  ForkPostElectra,
-  ForkSeq,
-  INTERVALS_PER_SLOT,
-  MAX_SEED_LOOKAHEAD,
-  SLOTS_PER_EPOCH,
-} from "@lodestar/params";
+import {ForkPostAltair, ForkPostElectra, ForkSeq, MAX_SEED_LOOKAHEAD, SLOTS_PER_EPOCH} from "@lodestar/params";
 import {
   CachedBeaconStateAltair,
   EpochCache,
@@ -267,8 +260,9 @@ export async function importBlock(
       // We want to track recent blocks coming from gossip, unknown block sync, and API.
       if (delaySec < SLOTS_PER_EPOCH * this.config.SECONDS_PER_SLOT) {
         this.metrics.importBlock.elapsedTimeTillBecomeHead.observe(delaySec);
-        if (delaySec > this.config.SECONDS_PER_SLOT / INTERVALS_PER_SLOT) {
-          this.metrics.importBlock.setHeadAfterFirstInterval.inc();
+        const cutOffSec = this.config.getAttestationDueMs(this.config.getForkName(blockSlot)) / 1000;
+        if (delaySec > cutOffSec) {
+          this.metrics.importBlock.setHeadAfterCutoff.inc();
         }
       }
     }

@@ -254,20 +254,9 @@ export class BeaconChain implements IBeaconChain {
     if (!clock) clock = new Clock({config, genesisTime: this.genesisTime, signal});
 
     this.blacklistedBlocks = new Map((opts.blacklistedBlocks ?? []).map((hex) => [hex, null]));
-    const preAggregateCutOffTime = (2 / 3) * this.config.SECONDS_PER_SLOT;
-    this.attestationPool = new AttestationPool(
-      config,
-      clock,
-      preAggregateCutOffTime,
-      this.opts?.preaggregateSlotDistance,
-      metrics
-    );
+    this.attestationPool = new AttestationPool(config, clock, this.opts?.preaggregateSlotDistance, metrics);
     this.aggregatedAttestationPool = new AggregatedAttestationPool(this.config, metrics);
-    this.syncCommitteeMessagePool = new SyncCommitteeMessagePool(
-      clock,
-      preAggregateCutOffTime,
-      this.opts?.preaggregateSlotDistance
-    );
+    this.syncCommitteeMessagePool = new SyncCommitteeMessagePool(config, clock, this.opts?.preaggregateSlotDistance);
     this.syncContributionAndProofPool = new SyncContributionAndProofPool(clock, metrics, logger);
 
     this.seenAggregatedAttestations = new SeenAggregatedAttestations(metrics);

@@ -74,7 +74,6 @@ export class AttestationPool {
   constructor(
     private readonly config: ChainForkConfig,
     private readonly clock: IClock,
-    private readonly cutOffSecFromSlot: number,
     private readonly preaggregateSlotDistance = 0,
     private readonly metrics: Metrics | null = null
   ) {}
@@ -98,7 +97,7 @@ export class AttestationPool {
    * `SignedAggregateAndProof`.
    *
    * If the attestation is too old (low slot) to be included in the pool it is simply dropped
-   * and no error is returned. Also if it's at clock slot but come to the pool later than 2/3
+   * and no error is returned. Also if it's at clock slot but come to the pool later than AGGREGATE_DUE_BPS
    * of slot time, it's dropped too since it's not helpful for the validator anymore
    *
    * Expects the attestation to be fully validated:
@@ -126,7 +125,7 @@ export class AttestationPool {
 
     // Reject gossip attestations in the current slot but come to this pool very late
     // for api attestations, we allow them to be added to the pool
-    if (!priority && this.clock.secFromSlot(slot) > this.cutOffSecFromSlot) {
+    if (!priority && this.clock.msFromSlot(slot) > this.config.getAggregateDueMs(fork)) {
       return InsertOutcome.Late;
     }
 

@@ -1,5 +1,6 @@
 import {Signature, aggregateSignatures} from "@chainsafe/blst";
 import {BitArray} from "@chainsafe/ssz";
+import {ChainForkConfig} from "@lodestar/config";
 import {SYNC_COMMITTEE_SIZE, SYNC_COMMITTEE_SUBNET_COUNT} from "@lodestar/params";
 import {Root, Slot, SubcommitteeIndex, SubnetID, altair} from "@lodestar/types";
 import {MapDef, toRootHex} from "@lodestar/utils";
@@ -44,8 +45,8 @@ export class SyncCommitteeMessagePool {
   private lowestPermissibleSlot = 0;
 
   constructor(
+    private readonly config: ChainForkConfig,
     private readonly clock: IClock,
-    private readonly cutOffSecFromSlot: number,
     private readonly preaggregateSlotDistance = 0
   ) {}
 
@@ -68,6 +69,7 @@ export class SyncCommitteeMessagePool {
     priority?: boolean
   ): InsertOutcome {
     const {slot, beaconBlockRoot} = signature;
+    const fork = this.config.getForkName(slot);
     const rootHex = toRootHex(beaconBlockRoot);
     const lowestPermissibleSlot = this.lowestPermissibleSlot;
 
@@ -76,8 +78,8 @@ export class SyncCommitteeMessagePool {
       return InsertOutcome.Old;
     }
 
-    // validator gets SyncCommitteeContribution at 2/3 of slot, it's no use to preaggregate later than that time
-    if (!priority && this.clock.secFromSlot(slot) > this.cutOffSecFromSlot) {
+    // validator gets SyncCommitteeContribution at CONTRIBUTION_DUE_BPS of slot, it's no use to preaggregate later than that time
+    if (!priority && this.clock.msFromSlot(slot) > this.config.getSyncContributionDueMs(fork)) {
       return InsertOutcome.Late;
     }
 

@@ -13,7 +13,7 @@ export enum InsertOutcome {
   Old = "Old",
   /** The pool has reached its limit. No changes were made. */
   ReachLimit = "ReachLimit",
-  /** Messages don't bring any value, for example attestations come to the pool at > 2/3 of slot. No changes were made */
+  /** Messages don't bring any value, for example attestations come to the pool at > AGGREGATE_DUE_BPS of slot. No changes were made */
   Late = "Late",
   /** The data is know, and the new participants have been added to the aggregated signature */
   Aggregated = "Aggregated",

@@ -22,17 +22,18 @@ import {IBeaconChain} from "./interface.js";
 import {getPayloadAttributesForSSE, prepareExecutionPayload} from "./produceBlock/produceBlockBody.js";
 import {RegenCaller} from "./regen/index.js";
 
-/* With 12s slot times, this scheduler will run 4s before the start of each slot (`12 / 3 = 4`). */
-export const SCHEDULER_LOOKAHEAD_FACTOR = 3;
+// TODO GLOAS: re-evaluate this timing
+/* With 12s slot times, this scheduler will run 4s before the start of each slot (`12 - 0.6667 * 12 = 4`). */
+export const PREPARE_NEXT_SLOT_BPS = 6667;
 
 /* We don't want to do more epoch transition than this */
 const PREPARE_EPOCH_LIMIT = 1;
 
 /**
  * At Bellatrix, if we are responsible for proposing in next slot, we want to prepare payload
- * 4s (1/3 slot) before the start of next slot
+ * 4s before the start of next slot at PREPARE_NEXT_SLOT_BPS of the current slot.
  *
- * For all forks, when clock is 1/3 slot before an epoch, we want to prepare for the next epoch
+ * For all forks, when clock reaches PREPARE_NEXT_SLOT_BPS of slot before an epoch, we want to prepare for the next epoch
  * transition from our head so that:
  * + validators vote for block head on time through attestation
  * + validators propose blocks on time
@@ -74,10 +75,9 @@ export class PrepareNextSlotScheduler {
     }
 
     try {
-      // At 1/3 slot time before the next slot, we either prepare payload or precompute
-      // epoch transition
-      const slotMs = this.config.SECONDS_PER_SLOT * 1000;
-      await sleep(slotMs - slotMs / SCHEDULER_LOOKAHEAD_FACTOR, this.signal);
+      // At PREPARE_NEXT_SLOT_BPS (~67%) of the current slot we prepare payload for the next slot
+      // or precompute epoch transition
+      await sleep(this.config.getSlotComponentDurationMs(PREPARE_NEXT_SLOT_BPS), this.signal);
 
       // calling updateHead() here before we produce a block to reduce reorg possibility
       const {slot: headSlot, blockRoot: headRoot} = this.chain.recomputeForkChoiceHead(

@@ -1,5 +1,4 @@
 import {routes} from "@lodestar/api";
-import {INTERVALS_PER_SLOT} from "@lodestar/params";
 import {
   CachedBeaconStateAllForks,
   computeStartSlotAtEpoch,
@@ -59,6 +58,9 @@ type LoadedStateBytesData = {persistedKey: DatastoreKey; stateBytes: Uint8Array}
  */
 export const DEFAULT_MAX_CP_STATE_EPOCHS_IN_MEMORY = 3;
 
+// TODO GLOAS: re-evaluate this timing
+const PROCESS_CHECKPOINT_STATES_BPS = 6667;
+
 /**
  * An implementation of CheckpointStateCache that keep up to n epoch checkpoint states in memory and persist the rest to disk
  * - If it's more than `maxEpochsInMemory` epochs old, it will persist n last epochs to disk based on the view of the block
@@ -464,14 +466,14 @@ export class PersistentCheckpointStateCache implements CheckpointStateCache {
     }
 
     const blockSlot = state.slot;
-    const twoThirdsSlot = (2 * state.config.SECONDS_PER_SLOT) / INTERVALS_PER_SLOT;
+    const processCPStatesTimeMs = state.config.getSlotComponentDurationMs(PROCESS_CHECKPOINT_STATES_BPS);
     // we always have clock in production, fallback value is only for test
-    const secFromSlot = this.clock?.secFromSlot(blockSlot) ?? twoThirdsSlot;
-    const secToTwoThirdsSlot = twoThirdsSlot - secFromSlot;
-    if (secToTwoThirdsSlot > 0) {
-      // 2/3 of slot is the most free time of every slot, take that chance to persist checkpoint states
-      // normally it should only persist checkpoint states at 2/3 of slot 0 of epoch
-      await sleep(secToTwoThirdsSlot * 1000, this.signal);
+    const msFromSlot = this.clock?.msFromSlot(blockSlot) ?? processCPStatesTimeMs;
+    const msToProcessCPStates = processCPStatesTimeMs - msFromSlot;
+    if (msToProcessCPStates > 0) {
+      // At ~67% of slot is the most free time of every slot, take that chance to persist checkpoint states
+      // normally it should only persist checkpoint states at ~67% of slot 0 of epoch
+      await sleep(msToProcessCPStates, this.signal);
     }
     // at syncing time, it's critical to persist checkpoint states as soon as possible to avoid OOM during unfinality time
     // if node is synced this is not a hot time because block comes late, we'll likely miss attestation already, or the block is orphaned

@@ -25,9 +25,10 @@ export function validateLightClientFinalityUpdate(
   }
 
   // [IGNORE] The finality_update is received after the block at signature_slot was given enough time to propagate
-  // through the network -- i.e. validate that one-third of finality_update.signature_slot has transpired
-  // (SECONDS_PER_SLOT / INTERVALS_PER_SLOT seconds after the start of the slot, with a MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance)
-  if (updateReceivedTooEarly(config, chain.genesisTime, gossipedFinalityUpdate)) {
+  // through the network -- i.e. validate that `get_sync_message_due_ms(epoch)`
+  // milliseconds (with a `MAXIMUM_GOSSIP_CLOCK_DISPARITY` allowance) has
+  // transpired since the start of `signature_slot`.
+  if (updateReceivedTooEarly(config, chain.clock, gossipedFinalityUpdate)) {
     throw new LightClientError(GossipAction.IGNORE, {
       code: LightClientErrorCode.FINALITY_UPDATE_RECEIVED_TOO_EARLY,
     });

@@ -1,8 +1,8 @@
 import {ChainForkConfig} from "@lodestar/config";
-import {computeTimeAtSlot} from "@lodestar/state-transition";
 import {LightClientOptimisticUpdate} from "@lodestar/types";
 import {MAXIMUM_GOSSIP_CLOCK_DISPARITY} from "../../constants/index.js";
 import {assertLightClientServer} from "../../node/utils/lightclient.js";
+import {IClock} from "../../util/clock.js";
 import {GossipAction} from "../errors/index.js";
 import {LightClientError, LightClientErrorCode} from "../errors/lightClientError.js";
 import {IBeaconChain} from "../interface.js";
@@ -26,9 +26,10 @@ export function validateLightClientOptimisticUpdate(
   }
 
   // [IGNORE] The optimistic_update is received after the block at signature_slot was given enough time to propagate
-  // through the network -- i.e. validate that one-third of optimistic_update.signature_slot has transpired
-  // (SECONDS_PER_SLOT / INTERVALS_PER_SLOT seconds after the start of the slot, with a MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance)
-  if (updateReceivedTooEarly(config, chain.genesisTime, gossipedOptimisticUpdate)) {
+  // through the network -- i.e. validate that `get_sync_message_due_ms(epoch)`
+  // milliseconds (with a `MAXIMUM_GOSSIP_CLOCK_DISPARITY` allowance) has
+  // transpired since the start of `signature_slot`.
+  if (updateReceivedTooEarly(config, chain.clock, gossipedOptimisticUpdate)) {
     throw new LightClientError(GossipAction.IGNORE, {
       code: LightClientErrorCode.OPTIMISTIC_UPDATE_RECEIVED_TOO_EARLY,
     });
@@ -48,20 +49,20 @@ export function validateLightClientOptimisticUpdate(
 /**
  * Returns true, if the spec condition below triggers an IGNORE.
  *
- *      Sig +1/3 time
+ *      Sig + SYNC_MESSAGE_DUE_BPS time
  * -----|-----
  * xxx|-------  (x is not okay)
  *
  * [IGNORE] The *update is received after the block at signature_slot was given enough time to propagate
- * through the network -- i.e. validate that one-third of *update.signature_slot has transpired
- * (SECONDS_PER_SLOT / INTERVALS_PER_SLOT seconds after the start of the slot, with a MAXIMUM_GOSSIP_CLOCK_DISPARITY allowance)
+ * through the network -- i.e. validate that `get_sync_message_due_ms(epoch)`
+ * milliseconds (with a `MAXIMUM_GOSSIP_CLOCK_DISPARITY` allowance) has
+ * transpired since the start of `signature_slot`.
  */
 export function updateReceivedTooEarly(
   config: ChainForkConfig,
-  genesisTime: number,
+  clock: IClock,
   update: Pick<LightClientOptimisticUpdate, "signatureSlot">
 ): boolean {
-  const signatureSlot13TimestampMs = computeTimeAtSlot(config, update.signatureSlot + 1 / 3, genesisTime) * 1000;
-  const earliestAllowedTimestampMs = signatureSlot13TimestampMs - MAXIMUM_GOSSIP_CLOCK_DISPARITY;
-  return Date.now() < earliestAllowedTimestampMs;
+  const fork = config.getForkName(update.signatureSlot);
+  return clock.msFromSlot(update.signatureSlot) < config.getSyncMessageDueMs(fork) - MAXIMUM_GOSSIP_CLOCK_DISPARITY;
 }