Fast Finality Tracking

The FastFinalityTracking contract is responsible for tracking and scoring validator performance based on their participation in finalizing blocks. This mechanism ensures the reliability of validators by incentivizing active participation and maintaining a secure and efficient network.

Key Responsibilities

  1. Tracking Finality Votes:

    • Records votes submitted by validators for block finality.
    • Keeps a count of finality votes (qcVoteCount) for each validator in each epoch.

  2. Scoring Validators:

    • Assigns scores to validators based on the quality of their finality votes and their normalized stake values.
    • Scores are calculated dynamically for each epoch to reflect validator performance accurately.

  3. Normalizing Stake Data:

    • Ensures fair scoring by normalizing staking amounts across all validators.
    • Applies a pivot-based normalization to cap excessive stakes and balance scoring metrics.

  4. Integration with Epochs and Periods:

    • Operates on an epoch-based system to ensure timely and accurate tracking of validator actions.
    • Normalized data is updated per period for consistent calculations.

Workflow

1. Recording Finality Votes

  • The recordFinality function is called by the block producer (via block.coinbase) once per block.
  • Validators who voted for block finality are recorded.
  • Scores are updated for each validator based on:
    • Their normalized stake.
    • The total normalized stake of voters.

2. Normalization of Stake Values

  • Stake values are normalized using the inplaceFindNormalizedSumAndPivot function from LibArray:
    • Excessively large stakes are capped to prevent unfair advantages.
    • The normalized stake values are stored for future calculations.

3. Scoring Validators

  • The scoring formula accounts for:
    • Total stake of the validator (including self-stake and delegator stake amounts).
    • The validator’s normalized stake.
    • The total normalized stake of voters.
    • The ratio of votes cast to the total possible votes.
  • Scores reflect the contribution of each validator to the block finality process.

4. Epoch-Based Tracking

  • Votes and scores are tracked for each epoch.
  • The epochOf function from the RoninValidatorSet contract is used to determine the current epoch based on the block number.

Data Structure

Tracking Records

  • _tracker:
    • Maps each epoch to a list of records for validators.
    • Each record includes:
      • qcVoteCount: The number of finality votes cast by the validator.
      • score: The cumulative score for the validator in the epoch.

Normalized Data

  • _normalizedData:
    • Stores normalized stake values for each validator in a period.
    • Includes:
      • normalizedStake: A mapping of validator IDs to their normalized stake values.
      • normalizedSum: The total normalized stake in the period.