Skip to content

Commit

Permalink
Correct Bank timestamp drift every slot (#12737) (#12777)
Browse files Browse the repository at this point in the history 
* Move timestamp helper to sdk

* Add Bank method for getting timestamp estimate

* Return sysvar info from Bank::clock

* Add feature-gated timestamp correction

* Rename unix_timestamp method to be more descriptive

* Review comments

* Add timestamp metric

(cherry picked from commit b028c47)

# Conflicts:
#	runtime/src/feature_set.rs

Co-authored-by: Tyera Eulberg <teulberg@gmail.com>
  • Loading branch information
@mergify @CriesofCarrots
mergify[bot] and CriesofCarrots authored Oct 10, 2020
1 parent 2996ceb commit 567a1cb
Show file tree
Hide file tree
Showing 5 changed files with 418 additions and 152 deletions.
139 changes: 2 additions & 137 deletions ledger/src/blockstore.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,7 @@ use solana_sdk::{
program_utils::limited_deserialize,
pubkey::Pubkey,
signature::{Keypair, Signature, Signer},
stake_weighted_timestamp::{calculate_stake_weighted_timestamp, TIMESTAMP_SLOT_RANGE},
timing::timestamp,
transaction::Transaction,
};
Expand Down Expand Up @@ -77,7 +78,6 @@ thread_local!(static PAR_THREAD_POOL_ALL_CPUS: RefCell<ThreadPool> = RefCell::ne
pub const MAX_COMPLETED_SLOTS_IN_CHANNEL: usize = 100_000;
pub const MAX_TURBINE_PROPAGATION_IN_MS: u64 = 100;
pub const MAX_TURBINE_DELAY_IN_TICKS: u64 = MAX_TURBINE_PROPAGATION_IN_MS / MS_PER_TICK;
const TIMESTAMP_SLOT_RANGE: usize = 16;

// An upper bound on maximum number of data shreds we can handle in a slot
// 32K shreds would allow ~320K peak TPS
Expand Down Expand Up @@ -1630,7 +1630,7 @@ impl Blockstore {

let mut calculate_timestamp = Measure::start("calculate_timestamp");
let stake_weighted_timestamp =
calculate_stake_weighted_timestamp(unique_timestamps, stakes, slot, slot_duration)
calculate_stake_weighted_timestamp(&unique_timestamps, stakes, slot, slot_duration)
.ok_or(BlockstoreError::EmptyEpochStakes)?;
calculate_timestamp.stop();
datapoint_info!(
Expand Down Expand Up @@ -3130,33 +3130,6 @@ fn slot_has_updates(slot_meta: &SlotMeta, slot_meta_backup: &Option<SlotMeta>) -
(slot_meta_backup.is_some() && slot_meta_backup.as_ref().unwrap().consumed != slot_meta.consumed))
}

fn calculate_stake_weighted_timestamp(
unique_timestamps: HashMap<Pubkey, (Slot, UnixTimestamp)>,
stakes: &HashMap<Pubkey, (u64, Account)>,
slot: Slot,
slot_duration: Duration,
) -> Option<UnixTimestamp> {
let (stake_weighted_timestamps_sum, total_stake) = unique_timestamps
.into_iter()
.filter_map(|(vote_pubkey, (timestamp_slot, timestamp))| {
let offset = (slot - timestamp_slot) as u32 * slot_duration;
stakes.get(&vote_pubkey).map(|(stake, _account)| {
(
(timestamp as u128 + offset.as_secs() as u128) * *stake as u128,
stake,
)
})
})
.fold((0, 0), |(timestamps, stakes), (timestamp, stake)| {
(timestamps + timestamp, stakes + *stake as u128)
});
if total_stake > 0 {
Some((stake_weighted_timestamps_sum / total_stake) as i64)
} else {
None
}
}

// Creates a new ledger with slot 0 full of ticks (and only ticks).
//
// Returns the blockhash that can be used to append entries with.
Expand Down Expand Up @@ -3478,7 +3451,6 @@ pub mod tests {
hash::{self, hash, Hash},
instruction::CompiledInstruction,
message::Message,
native_token::sol_to_lamports,
packet::PACKET_DATA_SIZE,
pubkey::Pubkey,
signature::Signature,
Expand Down Expand Up @@ -5889,113 +5861,6 @@ pub mod tests {
}
}

#[test]
fn test_calculate_stake_weighted_timestamp() {
let recent_timestamp: UnixTimestamp = 1_578_909_061;
let slot = 5;
let slot_duration = Duration::from_millis(400);
let expected_offset = (slot * slot_duration).as_secs();
let pubkey0 = Pubkey::new_rand();
let pubkey1 = Pubkey::new_rand();
let pubkey2 = Pubkey::new_rand();
let pubkey3 = Pubkey::new_rand();
let unique_timestamps: HashMap<Pubkey, (Slot, UnixTimestamp)> = [
(pubkey0, (0, recent_timestamp)),
(pubkey1, (0, recent_timestamp)),
(pubkey2, (0, recent_timestamp)),
(pubkey3, (0, recent_timestamp)),
]
.iter()
.cloned()
.collect();

let stakes: HashMap<Pubkey, (u64, Account)> = [
(
pubkey0,
(
sol_to_lamports(4_500_000_000.0),
Account::new(1, 0, &Pubkey::default()),
),
),
(
pubkey1,
(
sol_to_lamports(4_500_000_000.0),
Account::new(1, 0, &Pubkey::default()),
),
),
(
pubkey2,
(
sol_to_lamports(4_500_000_000.0),
Account::new(1, 0, &Pubkey::default()),
),
),
(
pubkey3,
(
sol_to_lamports(4_500_000_000.0),
Account::new(1, 0, &Pubkey::default()),
),
),
]
.iter()
.cloned()
.collect();
assert_eq!(
calculate_stake_weighted_timestamp(
unique_timestamps.clone(),
&stakes,
slot as Slot,
slot_duration
),
Some(recent_timestamp + expected_offset as i64)
);

let stakes: HashMap<Pubkey, (u64, Account)> = [
(
pubkey0,
(
sol_to_lamports(15_000_000_000.0),
Account::new(1, 0, &Pubkey::default()),
),
),
(
pubkey1,
(
sol_to_lamports(1_000_000_000.0),
Account::new(1, 0, &Pubkey::default()),
),
),
(
pubkey2,
(
sol_to_lamports(1_000_000_000.0),
Account::new(1, 0, &Pubkey::default()),
),
),
(
pubkey3,
(
sol_to_lamports(1_000_000_000.0),
Account::new(1, 0, &Pubkey::default()),
),
),
]
.iter()
.cloned()
.collect();
assert_eq!(
calculate_stake_weighted_timestamp(
unique_timestamps,
&stakes,
slot as Slot,
slot_duration
),
Some(recent_timestamp + expected_offset as i64)
);
}

#[test]
fn test_persist_transaction_status() {
let blockstore_path = get_tmp_ledger_path!();
Expand Down
Loading

0 comments on commit 567a1cb

Please sign in to comment.