54cf94ea59
## Issue Addressed
Fixes a timing issue that results in spurious fork choice notifier failures:
```
WARN Error signalling fork choice waiter slot: 3962270, error: ForkChoiceSignalOutOfOrder { current: Slot(3962271), latest: Slot(3962270) }, service: beacon
```
There’s a fork choice run that is scheduled to run at the start of every slot by the `timer`, which creates a 12s interval timer when the beacon node starts up. The problem is that if there’s a bit of clock drift that gets corrected via NTP (or a leap second for that matter) then these 12s intervals will cease to line up with the start of the slot. This then creates the mismatch in slot number that we see above.
Lighthouse also runs fork choice 500ms before the slot begins, and these runs are what is conflicting with the start-of-slot runs. This means that the warning in current versions of Lighthouse is mostly cosmetic because fork choice is up to date with all but the most recent 500ms of attestations (which usually isn’t many).
## Proposed Changes
Fix the per-slot timer so that it continually re-calculates the duration to the start of the next slot and waits for that.
A side-effect of this change is that we may skip slots if the per-slot task takes >12s to run, but I think this is an unlikely scenario and an acceptable compromise.
Lighthouse: Ethereum consensus client
An open-source Ethereum consensus client, written in Rust and maintained by Sigma Prime.
Overview
Lighthouse is:
- Ready for use on Ethereum consensus mainnet.
- Fully open-source, licensed under Apache 2.0.
- Security-focused. Fuzzing techniques have been continuously applied and several external security reviews have been performed.
- Built in Rust, a modern language providing unique safety guarantees and excellent performance (comparable to C++).
- Funded by various organisations, including Sigma Prime, the Ethereum Foundation, ConsenSys, the Decentralization Foundation and private individuals.
- Actively involved in the specification and security analysis of the Ethereum proof-of-stake consensus specification.
Staking Deposit Contract
The Lighthouse team acknowledges
0x00000000219ab540356cBB839Cbe05303d7705Fa
as the canonical staking deposit contract address.
Documentation
The Lighthouse Book contains information for users and developers.
The Lighthouse team maintains a blog at lighthouse-blog.sigmaprime.io which contains periodical progress updates, roadmap insights and interesting findings.
Branches
Lighthouse maintains two permanent branches:
stable: Always points to the latest stable release.- This is ideal for most users.
unstable: Used for development, contains the latest PRs.- Developers should base their PRs on this branch.
Contributing
Lighthouse welcomes contributors.
If you are looking to contribute, please head to the Contributing section of the Lighthouse book.
Contact
The best place for discussion is the Lighthouse Discord server.
Sign up to the Lighthouse Development Updates mailing list for email notifications about releases, network status and other important information.
Encrypt sensitive messages using our PGP key.
Donations
Lighthouse is an open-source project and a public good. Funding public goods is hard and we're grateful for the donations we receive from the community via:
- Gitcoin Grants.
- Ethereum address:
0x25c4a76E7d118705e7Ea2e9b7d8C59930d8aCD3b(donation.sigmaprime.eth).