feat: use different snappy implementations for different topics #8670

twoeths · 2025-12-05T03:24:32Z

Motivation

snappy-wasm introduced different behaviour on different nodes: great on non-sas nodes but introduced performance regression on sas nodes, see feat: use snappy-wasm (#6483) #8647

Description

bring snappy-js implementation to lodestar
- a little improvement: use Buffer.allocUnsafe() there
use snappy-js for beacon_attestation topic type and snappy-wasm for other topics
this is deployed to feat3

gemini-code-assist · 2025-12-05T03:24:50Z

Summary of Changes

Hello @twoeths, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a strategic change to the Snappy decompression mechanism within the beacon node to resolve a performance bottleneck identified on SAS nodes. By selectively applying snappy-js for beacon_attestation messages and retaining snappy-wasm for other data, the system aims to optimize decompression efficiency. The changes involve integrating a new library, refactoring core data transformation logic, and ensuring robust error handling and test coverage for the new hybrid approach.

Highlights

Performance Improvement: Addresses a performance regression on SAS nodes caused by snappy-wasm by introducing a hybrid compression strategy.
Hybrid Snappy Decompression: Implements a dynamic selection mechanism to use snappy-js for beacon_attestation topic types (typically smaller payloads) and snappy-wasm for all other topics.
New Dependency: Adds snappyjs as a new dependency to the beacon-node package.
Refactored Decompression Logic: The inboundTransform function in encoding.ts has been refactored to utilize a new ISnappyDecompressor interface, allowing for different Snappy implementations to be used based on the topic type. Error messages for decompression failures have also been enhanced.
New Snappy-JS Implementation: Introduces a complete snappy-js implementation, including SnappyCompressor, SnappyDecompressor, and associated error handling, within the project.
Unit Tests: Adds new unit tests to validate the correct functioning of the hybrid snappy decompression logic across various data lengths and gossip types.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	`/gemini review`	Performs a code review for the current pull request in its current state.
Pull Request Summary	`/gemini summary`	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	`/gemini help`	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

gemini-code-assist

Code Review

This pull request introduces snappyjs for decompressing beacon_attestation messages to address performance regressions on certain nodes, while snappy-wasm is retained for other message types and all compression tasks. The changes are well-structured, using a decompressor interface and a factory function for selecting the appropriate implementation. My review focuses on improving the consistency and error handling between the two snappy implementations to make the new abstraction more robust.

packages/beacon-node/src/network/gossip/snappy/snappy-wasm.ts

packages/beacon-node/src/network/gossip/encoding.ts

wemeetagain · 2025-12-05T03:51:29Z

packages/beacon-node/src/network/gossip/snappy/index.ts

+ */
+export function getSnappyDecompressor(topicType: GossipType, data: Uint8Array): ISnappyDecompressor {
+  switch (topicType) {
+    case GossipType.beacon_attestation:


also aggregate and proof?

I switched to use snappy-wasm for data_column_sidecar and beacon_block
for others use snappy-js

wemeetagain · 2025-12-05T03:55:43Z

packages/beacon-node/src/network/gossip/snappy/snappy-js/index.ts

@@ -0,0 +1,56 @@
+import {SnappyCompressor} from "./compressor.js";


nice, this is snappyjs but converted to typescript?

should leave a comment here linking back to the upstream,
eg, // Based on snappyjs - https://github.com/zhipeng-jia/snappyjs

wemeetagain · 2025-12-05T03:58:57Z

packages/beacon-node/src/network/gossip/snappy/snappy-js/decompressor.ts

+    return -1;
+  }
+
+  uncompressInto(outBuffer: Uint8Array): boolean {


and we are now using this, which was previously hidden by our incomplete manually-crafted types

wemeetagain

can you update the snappy benchmarks with this impl of snappyjs?

twoeths · 2025-12-05T07:49:40Z

The high MarkSweepCompact gc issue on feat3 is still high until I switched back to Buffer.alloc()

codecov · 2025-12-08T13:21:54Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 52.03%. Comparing base (a6b3c51) to head (732860c).
⚠️ Report is 1 commits behind head on cayman/snappy.

Additional details and impacted files

@@              Coverage Diff               @@
##           cayman/snappy    #8670   +/-   ##
==============================================
  Coverage          52.03%   52.03%           
==============================================
  Files                848      848           
  Lines              65809    65807    -2     
  Branches            4809     4809           
==============================================
  Hits               34241    34241           
+ Misses             31499    31497    -2     
  Partials              69       69

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

**Motivation** - high `MarkSweepCompact` gc on #8647 - the reason is the use of `Buffer.allocUnsafe()` as found in #8670 (comment) - an alternative to #8670 **Description** - use `@chainsafe/snappy-wasm` for all topics but with `Buffer.alloc()` - this is deployed to `feat2` --------- Co-authored-by: Tuyen Nguyen <[email protected]>

wemeetagain · 2025-12-09T03:26:00Z

closing in favor of fix: use Buffer.alloc() with snappy-wasm #8671

twoeths added 3 commits December 5, 2025 09:08

feat: add snappyjs implementation in ts

4419e35

feat: implement ISnappyDecompressor interface

cbe7cfa

feat: use different uncompressor based on topic type

e717d37

twoeths requested a review from a team as a code owner December 5, 2025 03:24

twoeths changed the title ~~Te/cayman/snappy~~ feat: use different snappy implementations for different topics Dec 5, 2025

gemini-code-assist bot reviewed Dec 5, 2025

View reviewed changes

packages/beacon-node/src/network/gossip/snappy/snappy-wasm.ts Show resolved Hide resolved

packages/beacon-node/src/network/gossip/snappy/snappy-wasm.ts Show resolved Hide resolved

packages/beacon-node/src/network/gossip/encoding.ts Show resolved Hide resolved

twoeths added 2 commits December 5, 2025 10:29

fix: remove snappy-js

3f091e8

fix: make consistent behaviour across implementations

c94ede7

wemeetagain reviewed Dec 5, 2025

View reviewed changes

twoeths added 3 commits December 5, 2025 11:45

fix: use snappy-wasm for beacon_block and data_column_sidecar only

2d4de6a

fix: use Buffer.alloc()

a74d316

fix: update snappy benchmark using ISnappyDecompressor interface

95416e8

twoeths mentioned this pull request Dec 5, 2025

fix: use Buffer.alloc() with snappy-wasm #8671

Merged

chore: link to snappy-js upstream repo

732860c

wemeetagain closed this Dec 9, 2025

twoeths deleted the te/cayman/snappy branch December 9, 2025 06:22

		@@ -0,0 +1,56 @@
		import {SnappyCompressor} from "./compressor.js";

Uh oh!

feat: use different snappy implementations for different topics #8670

feat: use different snappy implementations for different topics #8670

Uh oh!

Conversation

twoeths commented Dec 5, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

gemini-code-assist bot commented Dec 5, 2025

Summary of Changes

Highlights

Footnotes

Uh oh!

gemini-code-assist bot left a comment

Choose a reason for hiding this comment

Code Review

Uh oh!

Uh oh!

Uh oh!

Uh oh!

wemeetagain Dec 5, 2025

Choose a reason for hiding this comment

Uh oh!

twoeths Dec 5, 2025

Choose a reason for hiding this comment

Uh oh!

wemeetagain Dec 5, 2025

Choose a reason for hiding this comment

Uh oh!

wemeetagain Dec 5, 2025

Choose a reason for hiding this comment

Uh oh!

wemeetagain Dec 5, 2025

Choose a reason for hiding this comment

Uh oh!

wemeetagain left a comment

Choose a reason for hiding this comment

Uh oh!

twoeths commented Dec 5, 2025

Uh oh!

codecov bot commented Dec 8, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Codecov Report

Uh oh!

wemeetagain commented Dec 9, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

twoeths commented Dec 5, 2025 •

edited

Loading

codecov bot commented Dec 8, 2025 •

edited

Loading