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Optimize attester slashing (#1745)

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## Issue Addressed

Closes #1548 

## Proposed Changes

Optimizes attester slashing choice by choosing the ones that cover the most amount of validators slashed, with the highest effective balances 

## Additional Info

Initial pass, need to write a test for it
This commit is contained in:
Daniel Schonfeld 2020-10-22 01:43:54 +00:00
parent 668513b67e
commit 8f86baa48d
4 changed files with 300 additions and 39 deletions
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3
beacon_node/beacon_chain/src/beacon_chain.rs
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@ -1725,7 +1725,8 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
state.latest_block_header.canonical_root()
};
let (proposer_slashings, attester_slashings) = self.op_pool.get_slashings(&state);
let (proposer_slashings, attester_slashings) =
self.op_pool.get_slashings(&state, &self.spec);
let eth1_data = eth1_chain.eth1_data_for_block_production(&state, &self.spec)?;
let deposits = eth1_chain

71
beacon_node/operation_pool/src/attester_slashing.rs Normal file
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@ -0,0 +1,71 @@
use crate::max_cover::MaxCover;
use state_processing::per_block_processing::get_slashable_indices_modular;
use std::collections::{HashMap, HashSet};
use types::{AttesterSlashing, BeaconState, ChainSpec, EthSpec};
pub struct AttesterSlashingMaxCover<'a, T: EthSpec> {
slashing: &'a AttesterSlashing<T>,
effective_balances: HashMap<u64, u64>,
}
impl<'a, T: EthSpec> AttesterSlashingMaxCover<'a, T> {
pub fn new(
slashing: &'a AttesterSlashing<T>,
proposer_slashing_indices: &HashSet<u64>,
state: &BeaconState<T>,
spec: &ChainSpec,
) -> Option<Self> {
let mut effective_balances: HashMap<u64, u64> = HashMap::new();
let epoch = state.current_epoch();
let slashable_validators =
get_slashable_indices_modular(state, slashing, |index, validator| {
validator.is_slashable_at(epoch) && !proposer_slashing_indices.contains(&index)
});
if let Ok(validators) = slashable_validators {
for vd in &validators {
let eff_balance = state.get_effective_balance(*vd as usize, spec).ok()?;
effective_balances.insert(*vd, eff_balance);
}
Some(Self {
slashing,
effective_balances,
})
} else {
None
}
}
}
impl<'a, T: EthSpec> MaxCover for AttesterSlashingMaxCover<'a, T> {
/// The result type, of which we would eventually like a collection of maximal quality.
type Object = AttesterSlashing<T>;
/// The type used to represent sets.
type Set = HashMap<u64, u64>;
/// Extract an object for inclusion in a solution.
fn object(&self) -> AttesterSlashing<T> {
self.slashing.clone()
}
/// Get the set of elements covered.
fn covering_set(&self) -> &HashMap<u64, u64> {
&self.effective_balances
}
/// Update the set of items covered, for the inclusion of some object in the solution.
fn update_covering_set(
&mut self,
_best_slashing: &AttesterSlashing<T>,
covered_validator_indices: &HashMap<u64, u64>,
) {
self.effective_balances
.retain(|k, _| !covered_validator_indices.contains_key(k));
}
/// The quality of this item's covering set, usually its cardinality.
fn score(&self) -> usize {
self.effective_balances.values().sum::<u64>() as usize
}
}

224
beacon_node/operation_pool/src/lib.rs
View File

@ -1,5 +1,6 @@
mod attestation;
mod attestation_id;
mod attester_slashing;
mod max_cover;
mod persistence;
@ -7,12 +8,12 @@ pub use persistence::PersistedOperationPool;
use attestation::AttMaxCover;
use attestation_id::AttestationId;
use attester_slashing::AttesterSlashingMaxCover;
use max_cover::maximum_cover;
use parking_lot::RwLock;
use state_processing::per_block_processing::errors::AttestationValidationError;
use state_processing::per_block_processing::{
get_slashable_indices, get_slashable_indices_modular, verify_attestation_for_block_inclusion,
verify_exit, VerifySignatures,
get_slashable_indices, verify_attestation_for_block_inclusion, verify_exit, VerifySignatures,
};
use state_processing::SigVerifiedOp;
use std::collections::{hash_map, HashMap, HashSet};
@ -23,7 +24,6 @@ use types::{
EthSpec, Fork, ForkVersion, Hash256, ProposerSlashing, RelativeEpoch, SignedVoluntaryExit,
Validator,
};
#[derive(Default, Debug)]
pub struct OperationPool<T: EthSpec + Default> {
/// Map from attestation ID (see below) to vectors of attestations.
@ -200,6 +200,7 @@ impl<T: EthSpec> OperationPool<T> {
pub fn get_slashings(
&self,
state: &BeaconState<T>,
spec: &ChainSpec,
) -> (Vec<ProposerSlashing>, Vec<AttesterSlashing<T>>) {
let proposer_slashings = filter_limit_operations(
self.proposer_slashings.read().values(),
@ -214,39 +215,25 @@ impl<T: EthSpec> OperationPool<T> {
// Set of validators to be slashed, so we don't attempt to construct invalid attester
// slashings.
let mut to_be_slashed = proposer_slashings
let to_be_slashed = proposer_slashings
.iter()
.map(|s| s.signed_header_1.message.proposer_index)
.collect::<HashSet<_>>();
let epoch = state.current_epoch();
let attester_slashings = self
.attester_slashings
.read()
.iter()
.filter(|(slashing, fork)| {
if *fork != state.fork.previous_version && *fork != state.fork.current_version {
return false;
}
let reader = self.attester_slashings.read();
// Take all slashings that will slash 1 or more validators.
let slashed_validators =
get_slashable_indices_modular(state, slashing, |index, validator| {
validator.is_slashable_at(epoch) && !to_be_slashed.contains(&index)
let relevant_attester_slashings = reader.iter().flat_map(|(slashing, fork)| {
if *fork == state.fork.previous_version || *fork == state.fork.current_version {
AttesterSlashingMaxCover::new(&slashing, &to_be_slashed, state, spec)
} else {
None
}
});
// Extend the `to_be_slashed` set so subsequent iterations don't try to include
// useless slashings.
if let Ok(validators) = slashed_validators {
to_be_slashed.extend(validators);
true
} else {
false
}
})
.take(T::MaxAttesterSlashings::to_usize())
.map(|(slashing, _)| slashing.clone())
.collect();
let attester_slashings = maximum_cover(
relevant_attester_slashings,
T::MaxAttesterSlashings::to_usize(),
);
(proposer_slashings, attester_slashings)
}
@ -960,6 +947,27 @@ mod release_tests {
&self.spec,
)
}
fn attester_slashing_two_indices(
&self,
slashed_indices_1: &[u64],
slashed_indices_2: &[u64],
) -> AttesterSlashing<MainnetEthSpec> {
let signer = |idx: u64, message: &[u8]| {
self.keypairs[idx as usize]
.sk
.sign(Hash256::from_slice(&message))
};
TestingAttesterSlashingBuilder::double_vote_with_additional_indices(
AttesterSlashingTestTask::Valid,
slashed_indices_1,
Some(slashed_indices_2),
signer,
&self.state.fork,
self.state.genesis_validators_root,
&self.spec,
)
}
}
/// Insert two slashings for the same proposer and ensure only one is returned.
@ -979,7 +987,7 @@ mod release_tests {
op_pool.insert_proposer_slashing(slashing2.clone().validate(state, spec).unwrap());
// Should only get the second slashing back.
assert_eq!(op_pool.get_slashings(state).0, vec![slashing2]);
assert_eq!(op_pool.get_slashings(state, spec).0, vec![slashing2]);
}
// Sanity check on the pruning of proposer slashings
@ -990,7 +998,7 @@ mod release_tests {
let slashing = ctxt.proposer_slashing(0);
op_pool.insert_proposer_slashing(slashing.clone().validate(state, spec).unwrap());
op_pool.prune_proposer_slashings(state);
assert_eq!(op_pool.get_slashings(state).0, vec![slashing]);
assert_eq!(op_pool.get_slashings(state, spec).0, vec![slashing]);
}
// Sanity check on the pruning of attester slashings
@ -1002,6 +1010,158 @@ mod release_tests {
op_pool
.insert_attester_slashing(slashing.clone().validate(state, spec).unwrap(), state.fork);
op_pool.prune_attester_slashings(state, state.fork);
assert_eq!(op_pool.get_slashings(state).1, vec![slashing]);
assert_eq!(op_pool.get_slashings(state, spec).1, vec![slashing]);
}
// Check that we get maximum coverage for attester slashings (highest qty of validators slashed)
#[test]
fn simple_max_cover_attester_slashing() {
let ctxt = TestContext::new();
let (op_pool, state, spec) = (&ctxt.op_pool, &ctxt.state, &ctxt.spec);
let slashing_1 = ctxt.attester_slashing(&[1]);
let slashing_2 = ctxt.attester_slashing(&[2, 3]);
let slashing_3 = ctxt.attester_slashing(&[4, 5, 6]);
let slashing_4 = ctxt.attester_slashing(&[7, 8, 9, 10]);
op_pool.insert_attester_slashing(
slashing_1.clone().validate(state, spec).unwrap(),
state.fork,
);
op_pool.insert_attester_slashing(
slashing_2.clone().validate(state, spec).unwrap(),
state.fork,
);
op_pool.insert_attester_slashing(
slashing_3.clone().validate(state, spec).unwrap(),
state.fork,
);
op_pool.insert_attester_slashing(
slashing_4.clone().validate(state, spec).unwrap(),
state.fork,
);
let best_slashings = op_pool.get_slashings(state, spec);
assert_eq!(best_slashings.1, vec![slashing_4, slashing_3]);
}
// Check that we get maximum coverage for attester slashings with overlapping indices
#[test]
fn overlapping_max_cover_attester_slashing() {
let ctxt = TestContext::new();
let (op_pool, state, spec) = (&ctxt.op_pool, &ctxt.state, &ctxt.spec);
let slashing_1 = ctxt.attester_slashing(&[1, 2, 3, 4]);
let slashing_2 = ctxt.attester_slashing(&[1, 2, 5]);
let slashing_3 = ctxt.attester_slashing(&[5, 6]);
let slashing_4 = ctxt.attester_slashing(&[6]);
op_pool.insert_attester_slashing(
slashing_1.clone().validate(state, spec).unwrap(),
state.fork,
);
op_pool.insert_attester_slashing(
slashing_2.clone().validate(state, spec).unwrap(),
state.fork,
);
op_pool.insert_attester_slashing(
slashing_3.clone().validate(state, spec).unwrap(),
state.fork,
);
op_pool.insert_attester_slashing(
slashing_4.clone().validate(state, spec).unwrap(),
state.fork,
);
let best_slashings = op_pool.get_slashings(state, spec);
assert_eq!(best_slashings.1, vec![slashing_1, slashing_3]);
}
// Max coverage of attester slashings taking into account proposer slashings
#[test]
fn max_coverage_attester_proposer_slashings() {
let ctxt = TestContext::new();
let (op_pool, state, spec) = (&ctxt.op_pool, &ctxt.state, &ctxt.spec);
let p_slashing = ctxt.proposer_slashing(1);
let a_slashing_1 = ctxt.attester_slashing(&[1, 2, 3, 4]);
let a_slashing_2 = ctxt.attester_slashing(&[1, 3, 4]);
let a_slashing_3 = ctxt.attester_slashing(&[5, 6]);
op_pool.insert_proposer_slashing(p_slashing.clone().validate(state, spec).unwrap());
op_pool.insert_attester_slashing(
a_slashing_1.clone().validate(state, spec).unwrap(),
state.fork,
);
op_pool.insert_attester_slashing(
a_slashing_2.clone().validate(state, spec).unwrap(),
state.fork,
);
op_pool.insert_attester_slashing(
a_slashing_3.clone().validate(state, spec).unwrap(),
state.fork,
);
let best_slashings = op_pool.get_slashings(state, spec);
assert_eq!(best_slashings.1, vec![a_slashing_1, a_slashing_3]);
}
//Max coverage checking that non overlapping indices are still recognized for their value
#[test]
fn max_coverage_different_indices_set() {
let ctxt = TestContext::new();
let (op_pool, state, spec) = (&ctxt.op_pool, &ctxt.state, &ctxt.spec);
let slashing_1 =
ctxt.attester_slashing_two_indices(&[1, 2, 3, 4, 5, 6], &[3, 4, 5, 6, 7, 8]);
let slashing_2 = ctxt.attester_slashing(&[5, 6]);
let slashing_3 = ctxt.attester_slashing(&[1, 2, 3]);
op_pool.insert_attester_slashing(
slashing_1.clone().validate(state, spec).unwrap(),
state.fork,
);
op_pool.insert_attester_slashing(
slashing_2.clone().validate(state, spec).unwrap(),
state.fork,
);
op_pool.insert_attester_slashing(
slashing_3.clone().validate(state, spec).unwrap(),
state.fork,
);
let best_slashings = op_pool.get_slashings(state, spec);
assert_eq!(best_slashings.1, vec![slashing_1, slashing_3]);
}
//Max coverage should be affected by the overall effective balances
#[test]
fn max_coverage_effective_balances() {
let mut ctxt = TestContext::new();
ctxt.state.validators[1].effective_balance = 17_000_000_000;
ctxt.state.validators[2].effective_balance = 17_000_000_000;
ctxt.state.validators[3].effective_balance = 17_000_000_000;
let (op_pool, state, spec) = (&ctxt.op_pool, &ctxt.state, &ctxt.spec);
let slashing_1 = ctxt.attester_slashing(&[1, 2, 3]);
let slashing_2 = ctxt.attester_slashing(&[4, 5, 6]);
let slashing_3 = ctxt.attester_slashing(&[7, 8]);
op_pool.insert_attester_slashing(
slashing_1.clone().validate(state, spec).unwrap(),
state.fork,
);
op_pool.insert_attester_slashing(
slashing_2.clone().validate(state, spec).unwrap(),
state.fork,
);
op_pool.insert_attester_slashing(
slashing_3.clone().validate(state, spec).unwrap(),
state.fork,
);
let best_slashings = op_pool.get_slashings(state, spec);
assert_eq!(best_slashings.1, vec![slashing_2, slashing_3]);
}
}

39
consensus/types/src/test_utils/builders/testing_attester_slashing_builder.rs
View File

@ -21,6 +21,29 @@ impl TestingAttesterSlashingBuilder {
genesis_validators_root: Hash256,
spec: &ChainSpec,
) -> AttesterSlashing<T>
where
F: Fn(u64, &[u8]) -> Signature,
{
TestingAttesterSlashingBuilder::double_vote_with_additional_indices(
test_task,
validator_indices,
None,
signer,
fork,
genesis_validators_root,
spec,
)
}
pub fn double_vote_with_additional_indices<F, T: EthSpec>(
test_task: AttesterSlashingTestTask,
validator_indices: &[u64],
additional_validator_indices: Option<&[u64]>,
signer: F,
fork: &Fork,
genesis_validators_root: Hash256,
spec: &ChainSpec,
) -> AttesterSlashing<T>
where
F: Fn(u64, &[u8]) -> Signature,
{
@ -73,13 +96,16 @@ impl TestingAttesterSlashingBuilder {
// Trigger bad validator indices ordering error.
vec![1, 0].into()
} else {
validator_indices.to_vec().into()
match additional_validator_indices {
Some(x) => x.to_vec().into(),
None => validator_indices.to_vec().into(),
}
},
data: data_2,
signature: AggregateSignature::empty(),
};
let add_signatures = |attestation: &mut IndexedAttestation<T>| {
let add_signatures = |attestation: &mut IndexedAttestation<T>, indices_to_sign: &[u64]| {
let domain = spec.get_domain(
attestation.data.target.epoch,
Domain::BeaconAttester,
@ -88,14 +114,17 @@ impl TestingAttesterSlashingBuilder {
);
let message = attestation.data.signing_root(domain);
for validator_index in validator_indices {
for validator_index in indices_to_sign {
let signature = signer(*validator_index, message.as_bytes());
attestation.signature.add_assign(&signature);
}
};
add_signatures(&mut attestation_1);
add_signatures(&mut attestation_2);
add_signatures(&mut attestation_1, validator_indices);
add_signatures(
&mut attestation_2,
additional_validator_indices.unwrap_or(validator_indices),
);
AttesterSlashing {
attestation_1,