diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md index 40363a666..6d0d84e12 100644 --- a/specs/core/0_beacon-chain.md +++ b/specs/core/0_beacon-chain.md @@ -93,6 +93,7 @@ - [`is_surround_vote`](#is_surround_vote) - [`integer_squareroot`](#integer_squareroot) - [`get_delayed_activation_exit_epoch`](#get_delayed_activation_exit_epoch) + - [`get_churn_limit`](#get_churn_limit) - [`bls_verify`](#bls_verify) - [`bls_verify_multiple`](#bls_verify_multiple) - [`bls_aggregate_pubkeys`](#bls_aggregate_pubkeys) @@ -182,8 +183,7 @@ These configurations are updated for releases, but may be out of sync during `de | `SHARD_COUNT` | `2**10` (= 1,024) | | `TARGET_COMMITTEE_SIZE` | `2**7` (= 128) | | `MAX_ATTESTATION_PARTICIPANTS` | `2**12` (= 4,096) | -| `MAX_EXITS_PER_EPOCH` | `2**2` (= 4) | -| `MAX_ACTIVATIONS_PER_FINALIZED_EPOCH` | `2**2` (= 4) | +| `MIN_PER_EPOCH_CHURN_LIMIT` | `2**2` (= 4) | | `SHUFFLE_ROUND_COUNT` | 90 | * For the safety of crosslinks `TARGET_COMMITTEE_SIZE` exceeds [the recommended minimum committee size of 111](https://vitalik.ca/files/Ithaca201807_Sharding.pdf); with sufficient active validators (at least `SLOTS_PER_EPOCH * TARGET_COMMITTEE_SIZE`), the shuffling algorithm ensures committee sizes of at least `TARGET_COMMITTEE_SIZE`. (Unbiasable randomness with a Verifiable Delay Function (VDF) will improve committee robustness and lower the safe minimum committee size.) @@ -233,6 +233,7 @@ These configurations are updated for releases, but may be out of sync during `de | `MIN_VALIDATOR_WITHDRAWABILITY_DELAY` | `2**8` (= 256) | epochs | ~27 hours | | `PERSISTENT_COMMITTEE_PERIOD` | `2**11` (= 2,048) | epochs | 9 days | | `MAX_CROSSLINK_EPOCHS` | `2**6` (= 64) | epochs | ~7 hours | +| `MAX_FULL_CHURN_EPOCHS` | `2**22` (= 4,194,304) | epochs | ~9 months | * `MAX_CROSSLINK_EPOCHS` should be a small constant times `SHARD_COUNT // SLOTS_PER_EPOCH` @@ -1269,6 +1270,15 @@ def get_delayed_activation_exit_epoch(epoch: Epoch) -> Epoch: return epoch + 1 + ACTIVATION_EXIT_DELAY ``` +### `get_churn_limit` + +```python +def get_churn_limit(state: BeaconState) -> int: + return max( + MIN_PER_EPOCH_CHURN_LIMIT, + MAX_FULL_CHURN_EPOCHS // len(get_active_validators(state, get_current_epoch(state))) + ) + ### `bls_verify` `bls_verify` is a function for verifying a BLS signature, defined in the [BLS Signature spec](../bls_signature.md#bls_verify). @@ -1321,7 +1331,7 @@ def initiate_validator_exit(state: BeaconState, index: ValidatorIndex) -> None: if state.exit_epoch < delayed_activation_exit_epoch: state.exit_epoch = delayed_activation_exit_epoch - if state.exit_queue_filled >= MAX_EXITS_PER_EPOCH: + if state.exit_queue_filled >= get_churn_limit(state): state.exit_epoch += 1 state.exit_queue_filled = 0 @@ -1962,7 +1972,7 @@ def update_registry(state: BeaconState) -> None: validator.activation_epoch >= get_delayed_activation_exit_epoch(state.finalized_epoch) ], key=lambda index: state.validator_registry[index].activation_eligibility_epoch) - for index in activation_queue[:MAX_ACTIVATIONS_PER_FINALIZED_EPOCH]: + for index in activation_queue[:get_churn_limit(state)]: activate_validator(state, index, is_genesis=False) state.latest_start_shard = (