fix: improve compute new state root when producing block (#6195)

* feat: track and call state.hashTreeRoot() in prepareNextSlot * fix: correct stateHashTreeRootTime bucket * docs: add more comment for the fix
ChainSafe · Dec 15, 2023 · c044d4c · c044d4c
1 parent 4658348
commit c044d4c
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Showing 4 changed files with 15 additions and 4 deletions.
diff --git a/packages/beacon-node/src/chain/blocks/verifyBlocksStateTransitionOnly.ts b/packages/beacon-node/src/chain/blocks/verifyBlocksStateTransitionOnly.ts
@@ -57,7 +57,7 @@ export async function verifyBlocksStateTransitionOnly(
       metrics
     );
 
-    const hashTreeRootTimer = metrics?.stateHashTreeRootTime.startTimer();
+    const hashTreeRootTimer = metrics?.stateHashTreeRootTime.startTimer({source: "block_transition"});
     const stateRoot = postState.hashTreeRoot();
     hashTreeRootTimer?.();
 

diff --git a/packages/beacon-node/src/chain/prepareNextSlot.ts b/packages/beacon-node/src/chain/prepareNextSlot.ts
@@ -104,6 +104,12 @@ export class PrepareNextSlotScheduler {
         RegenCaller.precomputeEpoch
       );
 
+      // cache HashObjects for faster hashTreeRoot() later, especially for computeNewStateRoot() if we need to produce a block at slot 0 of epoch
+      // see https://github.com/ChainSafe/lodestar/issues/6194
+      const hashTreeRootTimer = this.metrics?.stateHashTreeRootTime.startTimer({source: "prepare_next_slot"});
+      prepareState.hashTreeRoot();
+      hashTreeRootTimer?.();
+
       // assuming there is no reorg, it caches the checkpoint state & helps avoid doing a full state transition in the next slot
       //  + when gossip block comes, we need to validate and run state transition
       //  + if next slot is a skipped slot, it'd help getting target checkpoint state faster to validate attestations

diff --git a/packages/beacon-node/src/chain/produceBlock/computeNewStateRoot.ts b/packages/beacon-node/src/chain/produceBlock/computeNewStateRoot.ts
@@ -44,5 +44,9 @@ export function computeNewStateRoot(
   const {attestations, syncAggregate, slashing} = postState.proposerRewards;
   const proposerReward = BigInt(attestations + syncAggregate + slashing);
 
-  return {newStateRoot: postState.hashTreeRoot(), proposerReward};
+  const hashTreeRootTimer = metrics?.stateHashTreeRootTime.startTimer({source: "compute_new_state_root"});
+  const newStateRoot = postState.hashTreeRoot();
+  hashTreeRootTimer?.();
+
+  return {newStateRoot, proposerReward};
 }
diff --git a/packages/beacon-node/src/metrics/metrics/lodestar.ts b/packages/beacon-node/src/metrics/metrics/lodestar.ts
@@ -304,10 +304,11 @@ export function createLodestarMetrics(
       help: "Time to call commit after process a single block in seconds",
       buckets: [0.005, 0.01, 0.02, 0.05, 0.1, 1],
     }),
-    stateHashTreeRootTime: register.histogram({
+    stateHashTreeRootTime: register.histogram<"source">({
       name: "lodestar_stfn_hash_tree_root_seconds",
       help: "Time to compute the hash tree root of a post state in seconds",
-      buckets: [0.005, 0.01, 0.02, 0.05, 0.1, 1],
+      buckets: [0.05, 0.1, 0.2, 0.5, 1, 1.5],
+      labelNames: ["source"],
     }),
     preStateBalancesNodesPopulatedMiss: register.gauge<"source">({
       name: "lodestar_stfn_balances_nodes_populated_miss_total",