feat: reuse arrays for getAll() api consumers

packages/state-transition/src/block/processEth1Data.ts

@@ -23,6 +23,10 @@ export function processEth1Data(state: CachedBeaconStateAllForks, eth1Data: phas
   state.eth1DataVotes.push(eth1DataView);
 }
 
+/**
+ * This data is reused and never gc.
+ */
+const eth1DataVotes = new Array<CompositeViewDU<typeof ssz.phase0.Eth1Data>>();
 /**
  * Returns true if adding the given `eth1Data` to `state.eth1DataVotes` would
  * result in a change to `state.eth1Data`.
@@ -48,7 +52,9 @@ export function becomesNewEth1Data(
   // Then isEqualEth1DataView compares cached roots (HashObject as of Jan 2022) which is much cheaper
   // than doing structural equality, which requires tree -> value conversions
   let sameVotesCount = 0;
-  const eth1DataVotes = state.eth1DataVotes.getAllReadonly();
+  // const eth1DataVotes = state.eth1DataVotes.getAllReadonly();
+  eth1DataVotes.length = state.eth1DataVotes.length;
+  state.eth1DataVotes.getAllReadonly(eth1DataVotes);
   for (let i = 0; i < eth1DataVotes.length; i++) {
     if (isEqualEth1DataView(eth1DataVotes[i], newEth1Data)) {
       sameVotesCount++;

packages/state-transition/src/cache/epochTransitionCache.ts

@@ -1,4 +1,4 @@
-import {Epoch, ValidatorIndex} from "@lodestar/types";
+import {Epoch, ValidatorIndex, phase0} from "@lodestar/types";
 import {intDiv} from "@lodestar/utils";
 import {EPOCHS_PER_SLASHINGS_VECTOR, FAR_FUTURE_EPOCH, ForkSeq, MAX_EFFECTIVE_BALANCE} from "@lodestar/params";
 
@@ -197,6 +197,12 @@ const proposerIndices = new Array<number>();
 const inclusionDelays = new Array<number>();
 /** WARNING: reused, never gc'd */
 const flags = new Array<number>();
+/**
+ * This data is reused and never gc.
+ */
+const validators = new Array<phase0.Validator>();
+const previousEpochParticipation = new Array<number>();
+const currentEpochParticipation = new Array<number>();
 
 export function beforeProcessEpoch(
   state: CachedBeaconStateAllForks,
@@ -224,7 +230,9 @@ export function beforeProcessEpoch(
   // To optimize memory each validator node in `state.validators` is represented with a special node type
   // `BranchNodeStruct` that represents the data as struct internally. This utility grabs the struct data directly
   // from the nodes without any extra transformation. The returned `validators` array contains native JS objects.
-  const validators = state.validators.getAllReadonlyValues();
+  validators.length = state.validators.length;
+  state.validators.getAllReadonlyValues(validators);
+
   const validatorCount = validators.length;
 
   // pre-fill with true (most validators are active)
@@ -391,8 +399,10 @@ export function beforeProcessEpoch(
       FLAG_CURR_HEAD_ATTESTER
     );
   } else {
-    const previousEpochParticipation = (state as CachedBeaconStateAltair).previousEpochParticipation.getAll();
-    const currentEpochParticipation = (state as CachedBeaconStateAltair).currentEpochParticipation.getAll();
+    previousEpochParticipation.length = (state as CachedBeaconStateAltair).previousEpochParticipation.length;
+    (state as CachedBeaconStateAltair).previousEpochParticipation.getAll(previousEpochParticipation);
+    currentEpochParticipation.length = (state as CachedBeaconStateAltair).currentEpochParticipation.length;
+    (state as CachedBeaconStateAltair).currentEpochParticipation.getAll(currentEpochParticipation);
     for (let i = 0; i < validatorCount; i++) {
       flags[i] |=
         // checking active status first is required to pass random spec tests in altair

packages/state-transition/src/epoch/getRewardsAndPenalties.ts

@@ -17,7 +17,7 @@ import {
   FLAG_PREV_TARGET_ATTESTER_UNSLASHED,
   hasMarkers,
 } from "../util/attesterStatus.js";
-import {isInInactivityLeak, newZeroedArray} from "../util/index.js";
+import {isInInactivityLeak} from "../util/index.js";
 
 type RewardPenaltyItem = {
   baseReward: number;
@@ -28,6 +28,11 @@ type RewardPenaltyItem = {
   timelyHeadReward: number;
 };
 
+/**
+ * This data is reused and never gc.
+ */
+const rewards = new Array<number>();
+const penalties = new Array<number>();
 /**
  * An aggregate of getFlagIndexDeltas and getInactivityPenaltyDeltas that loop through process.flags 1 time instead of 4.
  *
@@ -48,8 +53,12 @@ export function getRewardsAndPenaltiesAltair(
   // TODO: Is there a cheaper way to measure length that going to `state.validators`?
   const validatorCount = state.validators.length;
   const activeIncrements = cache.totalActiveStakeByIncrement;
-  const rewards = newZeroedArray(validatorCount);
-  const penalties = newZeroedArray(validatorCount);
+  // const rewards = newZeroedArray(validatorCount);
+  // const penalties = newZeroedArray(validatorCount);
+  rewards.length = validatorCount;
+  rewards.fill(0);
+  penalties.length = validatorCount;
+  penalties.fill(0);
 
   const isInInactivityLeakBn = isInInactivityLeak(state);
   // effectiveBalance is multiple of EFFECTIVE_BALANCE_INCREMENT and less than MAX_EFFECTIVE_BALANCE

packages/state-transition/src/epoch/processInactivityUpdates.ts

@@ -3,6 +3,11 @@ import {CachedBeaconStateAltair, EpochTransitionCache} from "../types.js";
 import * as attesterStatusUtil from "../util/attesterStatus.js";
 import {isInInactivityLeak} from "../util/index.js";
 
+/**
+ * This data is reused and never gc.
+ */
+const inactivityScoresArr = new Array<number>();
+
 /**
  * Mutates `inactivityScores` from pre-calculated validator flags.
  *
@@ -30,7 +35,8 @@ export function processInactivityUpdates(state: CachedBeaconStateAltair, cache:
   // this avoids importing FLAG_ELIGIBLE_ATTESTER inside the for loop, check the compiled code
   const {FLAG_PREV_TARGET_ATTESTER_UNSLASHED, hasMarkers} = attesterStatusUtil;
 
-  const inactivityScoresArr = inactivityScores.getAll();
+  inactivityScoresArr.length = state.validators.length;
+  inactivityScores.getAll(inactivityScoresArr);
 
   for (let j = 0; j < eligibleValidatorIndices.length; j++) {
     const i = eligibleValidatorIndices[j];

packages/state-transition/src/epoch/processRewardsAndPenalties.ts

@@ -9,6 +9,10 @@ import {
 import {getAttestationDeltas} from "./getAttestationDeltas.js";
 import {getRewardsAndPenaltiesAltair} from "./getRewardsAndPenalties.js";
 
+/**
+ * This data is reused and never gc.
+ */
+const balances = new Array<number>();
 /**
  * Iterate over all validator and compute rewards and penalties to apply to balances.
  *
@@ -25,7 +29,8 @@ export function processRewardsAndPenalties(
   }
 
   const [rewards, penalties] = getRewardsAndPenalties(state, cache);
-  const balances = state.balances.getAll();
+  balances.length = state.balances.length;
+  state.balances.getAll(balances);
 
   for (let i = 0, len = rewards.length; i < len; i++) {
     balances[i] += rewards[i] - penalties[i] - (slashingPenalties[i] ?? 0);

packages/state-transition/src/util/balance.ts

@@ -1,5 +1,5 @@
 import {EFFECTIVE_BALANCE_INCREMENT} from "@lodestar/params";
-import {Gwei, ValidatorIndex} from "@lodestar/types";
+import {Gwei, ValidatorIndex, phase0} from "@lodestar/types";
 import {bigIntMax} from "@lodestar/utils";
 import {EffectiveBalanceIncrements} from "../cache/effectiveBalanceIncrements.js";
 import {BeaconStateAllForks} from "..";
@@ -43,6 +43,11 @@ export function decreaseBalance(state: BeaconStateAllForks, index: ValidatorInde
   state.balances.set(index, Math.max(0, newBalance));
 }
 
+/**
+ * This data is reused and never gc.
+ */
+const validators = new Array<phase0.Validator>();
+
 /**
  * This method is used to get justified balances from a justified state.
  * This is consumed by forkchoice which based on delta so we return "by increment" (in ether) value,
@@ -63,7 +68,8 @@ export function getEffectiveBalanceIncrementsZeroInactive(
     validatorCount
   );
 
-  const validators = justifiedState.validators.getAllReadonly();
+  validators.length = validatorCount;
+  justifiedState.validators.getAllReadonlyValues(validators);
   let j = 0;
   for (let i = 0; i < validatorCount; i++) {
     if (i === activeIndices[j]) {

packages/state-transition/test/unit/cachedBeaconState.test.ts

@@ -84,6 +84,7 @@ describe("CachedBeaconState", () => {
             state.validators.get(i).effectiveBalance += 1;
           }
         }
+        state.commit();
 
         if (validatorCountDelta < 0) {
           state.validators = state.validators.sliceTo(state.validators.length - 1 + validatorCountDelta);