lighthouse/consensus/proto_array/src/fork_choice_test_definition.rs
Michael Sproul 775d222299 Enable proposer boost re-orging (#2860)
## Proposed Changes

With proposer boosting implemented (#2822) we have an opportunity to re-org out late blocks.

This PR adds three flags to the BN to control this behaviour:

* `--disable-proposer-reorgs`: turn aggressive re-orging off (it's on by default).
* `--proposer-reorg-threshold N`: attempt to orphan blocks with less than N% of the committee vote. If this parameter isn't set then N defaults to 20% when the feature is enabled.
* `--proposer-reorg-epochs-since-finalization N`: only attempt to re-org late blocks when the number of epochs since finalization is less than or equal to N. The default is 2 epochs, meaning re-orgs will only be attempted when the chain is finalizing optimally.

For safety Lighthouse will only attempt a re-org under very specific conditions:

1. The block being proposed is 1 slot after the canonical head, and the canonical head is 1 slot after its parent. i.e. at slot `n + 1` rather than building on the block from slot `n` we build on the block from slot `n - 1`.
2. The current canonical head received less than N% of the committee vote. N should be set depending on the proposer boost fraction itself, the fraction of the network that is believed to be applying it, and the size of the largest entity that could be hoarding votes.
3. The current canonical head arrived after the attestation deadline from our perspective. This condition was only added to support suppression of forkchoiceUpdated messages, but makes intuitive sense.
4. The block is being proposed in the first 2 seconds of the slot. This gives it time to propagate and receive the proposer boost.


## Additional Info

For the initial idea and background, see: https://github.com/ethereum/consensus-specs/pull/2353#issuecomment-950238004

There is also a specification for this feature here: https://github.com/ethereum/consensus-specs/pull/3034

Co-authored-by: Michael Sproul <micsproul@gmail.com>
Co-authored-by: pawan <pawandhananjay@gmail.com>
2022-12-13 09:57:26 +00:00

317 lines
12 KiB
Rust

mod execution_status;
mod ffg_updates;
mod no_votes;
mod votes;
use crate::proto_array::CountUnrealizedFull;
use crate::proto_array_fork_choice::{Block, ExecutionStatus, ProtoArrayForkChoice};
use crate::{InvalidationOperation, JustifiedBalances};
use serde_derive::{Deserialize, Serialize};
use std::collections::BTreeSet;
use types::{
AttestationShufflingId, Checkpoint, Epoch, EthSpec, ExecutionBlockHash, Hash256,
MainnetEthSpec, Slot,
};
pub use execution_status::*;
pub use ffg_updates::*;
pub use no_votes::*;
pub use votes::*;
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum Operation {
FindHead {
justified_checkpoint: Checkpoint,
finalized_checkpoint: Checkpoint,
justified_state_balances: Vec<u64>,
expected_head: Hash256,
},
ProposerBoostFindHead {
justified_checkpoint: Checkpoint,
finalized_checkpoint: Checkpoint,
justified_state_balances: Vec<u64>,
expected_head: Hash256,
proposer_boost_root: Hash256,
},
InvalidFindHead {
justified_checkpoint: Checkpoint,
finalized_checkpoint: Checkpoint,
justified_state_balances: Vec<u64>,
},
ProcessBlock {
slot: Slot,
root: Hash256,
parent_root: Hash256,
justified_checkpoint: Checkpoint,
finalized_checkpoint: Checkpoint,
},
ProcessAttestation {
validator_index: usize,
block_root: Hash256,
target_epoch: Epoch,
},
Prune {
finalized_root: Hash256,
prune_threshold: usize,
expected_len: usize,
},
InvalidatePayload {
head_block_root: Hash256,
latest_valid_ancestor_root: Option<ExecutionBlockHash>,
},
AssertWeight {
block_root: Hash256,
weight: u64,
},
}
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ForkChoiceTestDefinition {
pub finalized_block_slot: Slot,
pub justified_checkpoint: Checkpoint,
pub finalized_checkpoint: Checkpoint,
pub operations: Vec<Operation>,
}
impl ForkChoiceTestDefinition {
pub fn run(self) {
let mut spec = MainnetEthSpec::default_spec();
spec.proposer_score_boost = Some(50);
let junk_shuffling_id =
AttestationShufflingId::from_components(Epoch::new(0), Hash256::zero());
let mut fork_choice = ProtoArrayForkChoice::new::<MainnetEthSpec>(
self.finalized_block_slot,
Hash256::zero(),
self.justified_checkpoint,
self.finalized_checkpoint,
junk_shuffling_id.clone(),
junk_shuffling_id,
ExecutionStatus::Optimistic(ExecutionBlockHash::zero()),
CountUnrealizedFull::default(),
)
.expect("should create fork choice struct");
let equivocating_indices = BTreeSet::new();
for (op_index, op) in self.operations.into_iter().enumerate() {
match op.clone() {
Operation::FindHead {
justified_checkpoint,
finalized_checkpoint,
justified_state_balances,
expected_head,
} => {
let justified_balances =
JustifiedBalances::from_effective_balances(justified_state_balances)
.unwrap();
let head = fork_choice
.find_head::<MainnetEthSpec>(
justified_checkpoint,
finalized_checkpoint,
&justified_balances,
Hash256::zero(),
&equivocating_indices,
Slot::new(0),
&spec,
)
.unwrap_or_else(|e| {
panic!("find_head op at index {} returned error {}", op_index, e)
});
assert_eq!(
head, expected_head,
"Operation at index {} failed head check. Operation: {:?}",
op_index, op
);
check_bytes_round_trip(&fork_choice);
}
Operation::ProposerBoostFindHead {
justified_checkpoint,
finalized_checkpoint,
justified_state_balances,
expected_head,
proposer_boost_root,
} => {
let justified_balances =
JustifiedBalances::from_effective_balances(justified_state_balances)
.unwrap();
let head = fork_choice
.find_head::<MainnetEthSpec>(
justified_checkpoint,
finalized_checkpoint,
&justified_balances,
proposer_boost_root,
&equivocating_indices,
Slot::new(0),
&spec,
)
.unwrap_or_else(|e| {
panic!("find_head op at index {} returned error {}", op_index, e)
});
assert_eq!(
head, expected_head,
"Operation at index {} failed head check. Operation: {:?}",
op_index, op
);
check_bytes_round_trip(&fork_choice);
}
Operation::InvalidFindHead {
justified_checkpoint,
finalized_checkpoint,
justified_state_balances,
} => {
let justified_balances =
JustifiedBalances::from_effective_balances(justified_state_balances)
.unwrap();
let result = fork_choice.find_head::<MainnetEthSpec>(
justified_checkpoint,
finalized_checkpoint,
&justified_balances,
Hash256::zero(),
&equivocating_indices,
Slot::new(0),
&spec,
);
assert!(
result.is_err(),
"Operation at index {} . Operation: {:?}",
op_index,
op
);
check_bytes_round_trip(&fork_choice);
}
Operation::ProcessBlock {
slot,
root,
parent_root,
justified_checkpoint,
finalized_checkpoint,
} => {
let block = Block {
slot,
root,
parent_root: Some(parent_root),
state_root: Hash256::zero(),
target_root: Hash256::zero(),
current_epoch_shuffling_id: AttestationShufflingId::from_components(
Epoch::new(0),
Hash256::zero(),
),
next_epoch_shuffling_id: AttestationShufflingId::from_components(
Epoch::new(0),
Hash256::zero(),
),
justified_checkpoint,
finalized_checkpoint,
// All blocks are imported optimistically.
execution_status: ExecutionStatus::Optimistic(
ExecutionBlockHash::from_root(root),
),
unrealized_justified_checkpoint: None,
unrealized_finalized_checkpoint: None,
};
fork_choice
.process_block::<MainnetEthSpec>(block, slot)
.unwrap_or_else(|e| {
panic!(
"process_block op at index {} returned error: {:?}",
op_index, e
)
});
check_bytes_round_trip(&fork_choice);
}
Operation::ProcessAttestation {
validator_index,
block_root,
target_epoch,
} => {
fork_choice
.process_attestation(validator_index, block_root, target_epoch)
.unwrap_or_else(|_| {
panic!(
"process_attestation op at index {} returned error",
op_index
)
});
check_bytes_round_trip(&fork_choice);
}
Operation::Prune {
finalized_root,
prune_threshold,
expected_len,
} => {
fork_choice.set_prune_threshold(prune_threshold);
fork_choice
.maybe_prune(finalized_root)
.expect("update_finalized_root op at index {} returned error");
// Ensure that no pruning happened.
assert_eq!(
fork_choice.len(),
expected_len,
"Prune op at index {} failed with {} instead of {}",
op_index,
fork_choice.len(),
expected_len
);
}
Operation::InvalidatePayload {
head_block_root,
latest_valid_ancestor_root,
} => {
let op = if let Some(latest_valid_ancestor) = latest_valid_ancestor_root {
InvalidationOperation::InvalidateMany {
head_block_root,
always_invalidate_head: true,
latest_valid_ancestor,
}
} else {
InvalidationOperation::InvalidateOne {
block_root: head_block_root,
}
};
fork_choice
.process_execution_payload_invalidation(&op)
.unwrap()
}
Operation::AssertWeight { block_root, weight } => assert_eq!(
fork_choice.get_weight(&block_root).unwrap(),
weight,
"block weight"
),
}
}
}
}
/// Gives a root that is not the zero hash (unless i is `usize::max_value)`.
fn get_root(i: u64) -> Hash256 {
Hash256::from_low_u64_be(i + 1)
}
/// Gives a hash that is not the zero hash (unless i is `usize::max_value)`.
fn get_hash(i: u64) -> ExecutionBlockHash {
ExecutionBlockHash::from_root(get_root(i))
}
/// Gives a checkpoint with a root that is not the zero hash (unless i is `usize::max_value)`.
/// `Epoch` will always equal `i`.
fn get_checkpoint(i: u64) -> Checkpoint {
Checkpoint {
epoch: Epoch::new(i),
root: get_root(i),
}
}
fn check_bytes_round_trip(original: &ProtoArrayForkChoice) {
let bytes = original.as_bytes();
let decoded = ProtoArrayForkChoice::from_bytes(&bytes, CountUnrealizedFull::default())
.expect("fork choice should decode from bytes");
assert!(
*original == decoded,
"fork choice should encode and decode without change"
);
}