Set default builder_boost_factor to 90

[fredriksvantes]

Proposed Changes

PR Description

In order to help increase censorship resistance, I propose to change the default builder_boost_factor to 90. This means validators will prioritize local block building unless the bid from the external block builder is 10% or higher than what the validator would receive when building locally.

Looking at (stats), it can be seen that currently 63.7% of external builders are censoring transactions compared to 8.53% of validators who do local block building, so setting a minimum 10% as default can help increase the overall censorship resistance of the network.

It is still easy for users to opt out of this by manually setting the flag to 100, but many are likely to use the default which could help with censorship resistance for the network.

Documentation

• [X] I thought about documentation and added the doc-change-required label to this PR if updates are required.

Changelog

• [X] I thought about adding a changelog entry, and added one if I deemed necessary.

[fredriksvantes]

Nimbus: https://github.com/status-im/nimbus-eth2/pull/6103 Lighthouse: https://github.com/sigp/lighthouse/pull/5441 Lodestar: https://github.com/ChainSafe/lodestar/pull/6568 Teku: https://github.com/Consensys/teku/pull/8108 Prysm: https://github.com/prysmaticlabs/prysm/pull/13772

[realbigsean]

mentioned this on the CL call - I'm sort of philosophically opposed to this, it's an unexpected and opinionated default that takes advantage of a user's lack of awareness of the defaults

if we want to raise awareness of this feature and encourage users to set this to what they want, my preference would be to require --builder-boost-factor if --builder is used

[pawanjay176]

Strongly agree with Sean.

However, I think making the builder-boost-factor flag required on the builder flag should be combined with having docs to help users choose a good value based on their preferences, otherwise the likely case imo would be that everyone sets it to 100 just to satisfy the requirement.

[dapplion]

The rough consensus of the team appears to be against merging. I believe everyone is aligned with anti-censorship values, but this PR sets an opinionated default, a precedent the Lighthouse team has not yet set.

I'll leave open for a few more weeks, and close if there's no rebutal. To keep our count of open PRs low :)