Merge pull request #1866 from ethereum/tunable-genesis

Tunable genesis

configs/mainnet.yaml

@@ -76,8 +76,8 @@ BLS_WITHDRAWAL_PREFIX: 0x00
 
 # Time parameters
 # ---------------------------------------------------------------
-# 86400 seconds (1 day)
+# 172800 seconds (2 days)
-MIN_GENESIS_DELAY: 86400
+GENESIS_DELAY: 172800
 # 12 seconds
 SECONDS_PER_SLOT: 12
 # 2**0 (= 1) slots 12 seconds

configs/minimal.yaml

@@ -77,7 +77,7 @@ BLS_WITHDRAWAL_PREFIX: 0x00
 # Time parameters
 # ---------------------------------------------------------------
 # [customized] Faster to spin up testnets, but does not give validator reasonable warning time for genesis
-MIN_GENESIS_DELAY: 300
+GENESIS_DELAY: 300
 # [customized] Faster for testing purposes
 SECONDS_PER_SLOT: 6
 # 2**0 (= 1) slots 6 seconds

specs/phase0/beacon-chain.md

@@ -218,7 +218,7 @@ The following values are (non-configurable) constants used throughout the specif
 
 | Name | Value | Unit | Duration |
 | - | - | :-: | :-: |
-| `MIN_GENESIS_DELAY` | `86400` | seconds | 1 day |
+| `GENESIS_DELAY` | `172800` | seconds | 2 days |
 | `SECONDS_PER_SLOT` | `12` | seconds | 12 seconds |
 | `SECONDS_PER_ETH1_BLOCK` | `14` | seconds | 14 seconds |
 | `MIN_ATTESTATION_INCLUSION_DELAY` | `2**0` (= 1) | slots | 12 seconds |
@@ -1137,7 +1137,7 @@ Before the Ethereum 2.0 genesis has been triggered, and for every Ethereum 1.0 b
 - `eth1_timestamp` is the Unix timestamp corresponding to `eth1_block_hash`
 - `deposits` is the sequence of all deposits, ordered chronologically, up to (and including) the block with hash `eth1_block_hash`
 
-Eth1 blocks must only be considered once they are at least `SECONDS_PER_ETH1_BLOCK * ETH1_FOLLOW_DISTANCE` seconds old (i.e. `eth1_timestamp + SECONDS_PER_ETH1_BLOCK * ETH1_FOLLOW_DISTANCE <= current_unix_time`). Due to this constraint, if `MIN_GENESIS_DELAY < SECONDS_PER_ETH1_BLOCK * ETH1_FOLLOW_DISTANCE`, then the `genesis_time` can happen before the time/state is first known. Values should be configured to avoid this case.
+Eth1 blocks must only be considered once they are at least `SECONDS_PER_ETH1_BLOCK * ETH1_FOLLOW_DISTANCE` seconds old (i.e. `eth1_timestamp + SECONDS_PER_ETH1_BLOCK * ETH1_FOLLOW_DISTANCE <= current_unix_time`). Due to this constraint, if `GENESIS_DELAY < SECONDS_PER_ETH1_BLOCK * ETH1_FOLLOW_DISTANCE`, then the `genesis_time` can happen before the time/state is first known. Values should be configured to avoid this case.
 
 ```python
 def initialize_beacon_state_from_eth1(eth1_block_hash: Bytes32,
@@ -1149,7 +1149,7 @@ def initialize_beacon_state_from_eth1(eth1_block_hash: Bytes32,
         epoch=GENESIS_EPOCH,
     )
     state = BeaconState(
-        genesis_time=eth1_timestamp - eth1_timestamp % MIN_GENESIS_DELAY + 2 * MIN_GENESIS_DELAY,
+        genesis_time=eth1_timestamp + GENESIS_DELAY,
         fork=fork,
         eth1_data=Eth1Data(block_hash=eth1_block_hash, deposit_count=len(deposits)),
         latest_block_header=BeaconBlockHeader(body_root=hash_tree_root(BeaconBlockBody())),

specs/phase0/p2p-interface.md

@@ -1052,7 +1052,7 @@ discv5 uses ENRs and we will presumably need to:
 
 Although client software might very well be running locally prior to the solidification of the eth2 genesis state and block, clients cannot form valid ENRs prior to this point. ENRs contain `fork_digest` which utilizes the `genesis_validators_root` for a cleaner separation between chains so prior to knowing genesis, we cannot use `fork_digest` to cleanly find peers on our intended chain. Once genesis data is known, we can then form ENRs and safely find peers.
 
-When using an eth1 deposit contract for deposits, `fork_digest` will be known at least `MIN_GENESIS_DELAY` (24 hours in mainnet configuration) before `genesis_time`, providing ample time to find peers and form initial connections and gossip subnets prior to genesis.
+When using an eth1 deposit contract for deposits, `fork_digest` will be known `GENESIS_DELAY` (48hours in mainnet configuration) before `genesis_time`, providing ample time to find peers and form initial connections and gossip subnets prior to genesis.
 
 ## Compression/Encoding
 

tests/core/pyspec/eth2spec/test/genesis/test_initialization.py

@@ -21,7 +21,7 @@ def test_initialize_beacon_state_from_eth1(spec):
     # initialize beacon_state
     state = spec.initialize_beacon_state_from_eth1(eth1_block_hash, eth1_timestamp, deposits)
 
-    assert state.genesis_time == eth1_timestamp - eth1_timestamp % spec.MIN_GENESIS_DELAY + 2 * spec.MIN_GENESIS_DELAY
+    assert state.genesis_time == eth1_timestamp + spec.GENESIS_DELAY
     assert len(state.validators) == deposit_count
     assert state.eth1_data.deposit_root == deposit_root
     assert state.eth1_data.deposit_count == deposit_count
@@ -57,7 +57,7 @@ def test_initialize_beacon_state_some_small_balances(spec):
     # initialize beacon_state
     state = spec.initialize_beacon_state_from_eth1(eth1_block_hash, eth1_timestamp, deposits)
 
-    assert state.genesis_time == eth1_timestamp - eth1_timestamp % spec.MIN_GENESIS_DELAY + 2 * spec.MIN_GENESIS_DELAY
+    assert state.genesis_time == eth1_timestamp + spec.GENESIS_DELAY
     assert len(state.validators) == small_deposit_count
     assert state.eth1_data.deposit_root == deposit_root
     assert state.eth1_data.deposit_count == len(deposits)