Reject blocks for costs above the max block cost (#18994)

* added realtime cost checking logic to reject block that would exceed max limit:
- defines max limits at block_cost_limits.rs
- right after each bath's execution, accumulate its cost and check again
  limit, return error if limit is exceeded

* update abi that changed due to adding additional TransactionError

* To avoid counting stats mltiple times, only accumulate execute-timing when a bank is completed

* gate it by a feature

* move cost const def into block_cost_limits.rs

* redefine the cost for signature and account access, removed signer part as it is not well defined for now

* check if per_program_timings of execute_timings before sending
This commit is contained in:
Tao Zhu 2021-08-12 10:48:47 -05:00 committed by GitHub
parent 9d8594a046
commit 414d904959
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10 changed files with 159 additions and 47 deletions

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@ -9,30 +9,10 @@
//!
use crate::execute_cost_table::ExecuteCostTable;
use log::*;
use solana_ledger::block_cost_limits::*;
use solana_sdk::{pubkey::Pubkey, sanitized_transaction::SanitizedTransaction};
use std::collections::HashMap;
// 07-27-2021, compute_unit to microsecond conversion ratio collected from mainnet-beta
// differs between instructions. Some bpf instruction has much higher CU/US ratio
// (eg 7vxeyaXGLqcp66fFShqUdHxdacp4k4kwUpRSSeoZLCZ4 has average ratio 135), others
// have lower ratio (eg 9xQeWvG816bUx9EPjHmaT23yvVM2ZWbrrpZb9PusVFin has an average ratio 14).
// With this, I am guestimating the flat_fee for sigver and account read/write
// as following. This can be adjusted when needed.
const SIGVER_COST: u64 = 1;
const NON_SIGNED_READONLY_ACCOUNT_ACCESS_COST: u64 = 1;
const NON_SIGNED_WRITABLE_ACCOUNT_ACCESS_COST: u64 = 2;
const SIGNED_READONLY_ACCOUNT_ACCESS_COST: u64 =
SIGVER_COST + NON_SIGNED_READONLY_ACCOUNT_ACCESS_COST;
const SIGNED_WRITABLE_ACCOUNT_ACCESS_COST: u64 =
SIGVER_COST + NON_SIGNED_WRITABLE_ACCOUNT_ACCESS_COST;
// 07-27-2021, cost model limit is set to "worst case scenario", which is the
// max compute unit it can execute. From mainnet-beta, the max CU of instruction
// is 3753, round up to 4_000. Say we allows max 50_000 instruction per writable i
// account, and 1_000_000 instruction per block. It comes to following limits:
pub const ACCOUNT_MAX_COST: u64 = 200_000_000;
pub const BLOCK_MAX_COST: u64 = 4_000_000_000;
const MAX_WRITABLE_ACCOUNTS: usize = 256;
#[derive(Debug, Clone)]
@ -88,7 +68,7 @@ pub struct CostModel {
impl Default for CostModel {
fn default() -> Self {
CostModel::new(ACCOUNT_MAX_COST, BLOCK_MAX_COST)
CostModel::new(account_cost_max(), block_cost_max())
}
}
@ -142,21 +122,13 @@ impl CostModel {
// calculate account access cost
let message = transaction.message();
message.account_keys.iter().enumerate().for_each(|(i, k)| {
let is_signer = message.is_signer(i);
let is_writable = message.is_writable(i);
if is_signer && is_writable {
if is_writable {
self.transaction_cost.writable_accounts.push(*k);
self.transaction_cost.account_access_cost += SIGNED_WRITABLE_ACCOUNT_ACCESS_COST;
} else if is_signer && !is_writable {
self.transaction_cost.account_access_cost += SIGNED_READONLY_ACCOUNT_ACCESS_COST;
} else if !is_signer && is_writable {
self.transaction_cost.writable_accounts.push(*k);
self.transaction_cost.account_access_cost +=
NON_SIGNED_WRITABLE_ACCOUNT_ACCESS_COST;
self.transaction_cost.account_access_cost += account_write_cost();
} else {
self.transaction_cost.account_access_cost +=
NON_SIGNED_READONLY_ACCOUNT_ACCESS_COST;
self.transaction_cost.account_access_cost += account_read_cost();
}
});
debug!(
@ -418,9 +390,8 @@ mod tests {
.try_into()
.unwrap();
let expected_account_cost = SIGNED_WRITABLE_ACCOUNT_ACCESS_COST
+ NON_SIGNED_WRITABLE_ACCOUNT_ACCESS_COST
+ NON_SIGNED_READONLY_ACCOUNT_ACCESS_COST;
let expected_account_cost =
account_write_cost() + account_write_cost() + account_read_cost();
let expected_execution_cost = 8;
let mut cost_model = CostModel::default();
@ -475,9 +446,8 @@ mod tests {
);
let number_threads = 10;
let expected_account_cost = SIGNED_WRITABLE_ACCOUNT_ACCESS_COST
+ NON_SIGNED_WRITABLE_ACCOUNT_ACCESS_COST * 2
+ NON_SIGNED_READONLY_ACCOUNT_ACCESS_COST * 2;
let expected_account_cost =
account_write_cost() + account_write_cost() * 2 + account_read_cost() * 2;
let cost1 = 100;
let cost2 = 200;
// execution cost can be either 2 * Default (before write) or cost1+cost2 (after write)

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@ -1931,7 +1931,6 @@ impl ReplayStage {
replay_vote_sender,
verify_recyclers,
);
execute_timings.accumulate(&bank_progress.replay_stats.execute_timings);
match replay_result {
Ok(replay_tx_count) => tx_count += replay_tx_count,
Err(err) => {
@ -1957,6 +1956,12 @@ impl ReplayStage {
}
assert_eq!(*bank_slot, bank.slot());
if bank.is_complete() {
execute_timings.accumulate(&bank_progress.replay_stats.execute_timings);
debug!("bank {} is completed replay from blockstore, contribute to update cost with {:?}",
bank.slot(),
bank_progress.replay_stats.execute_timings
);
bank_progress.replay_stats.report_stats(
bank.slot(),
bank_progress.replay_progress.num_entries,
@ -2031,9 +2036,11 @@ impl ReplayStage {
}
// send accumulated excute-timings to cost_update_service
cost_update_sender
.send(execute_timings)
.unwrap_or_else(|err| warn!("cost_update_sender failed: {:?}", err));
if !execute_timings.details.per_program_timings.is_empty() {
cost_update_sender
.send(execute_timings)
.unwrap_or_else(|err| warn!("cost_update_sender failed: {:?}", err));
}
inc_new_counter_info!("replay_stage-replay_transactions", tx_count);
did_complete_bank

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@ -0,0 +1,42 @@
//! defines block cost related limits
//!
// see https://github.com/solana-labs/solana/issues/18944
// and https://github.com/solana-labs/solana/pull/18994#issuecomment-896128992
//
pub const MAX_BLOCK_TIME_US: u64 = 400_000; // aiming at 400ms/block max time
pub const AVG_INSTRUCTION_TIME_US: u64 = 1_000; // average instruction execution time
pub const SYSTEM_PARALLELISM: u64 = 10;
pub const MAX_INSTRUCTION_COST: u64 = 200_000;
pub const MAX_NUMBER_BPF_INSTRUCTIONS_PER_ACCOUNT: u64 = 200;
pub const fn max_instructions_per_block() -> u64 {
(MAX_BLOCK_TIME_US / AVG_INSTRUCTION_TIME_US) * SYSTEM_PARALLELISM
}
pub const fn block_cost_max() -> u64 {
MAX_INSTRUCTION_COST * max_instructions_per_block()
}
pub const fn account_cost_max() -> u64 {
MAX_INSTRUCTION_COST * max_instructions_per_block()
}
pub const fn compute_unit_to_us_ratio() -> u64 {
block_cost_max() / MAX_BLOCK_TIME_US
}
pub const fn signature_cost() -> u64 {
// signature takes average 10us
compute_unit_to_us_ratio() * 10
}
pub const fn account_read_cost() -> u64 {
// read account averages 5us
compute_unit_to_us_ratio() * 5
}
pub const fn account_write_cost() -> u64 {
// write account averages 25us
compute_unit_to_us_ratio() * 25
}

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@ -1,6 +1,7 @@
use crate::{
block_error::BlockError, blockstore::Blockstore, blockstore_db::BlockstoreError,
blockstore_meta::SlotMeta, leader_schedule_cache::LeaderScheduleCache,
block_cost_limits::*, block_error::BlockError, blockstore::Blockstore,
blockstore_db::BlockstoreError, blockstore_meta::SlotMeta,
leader_schedule_cache::LeaderScheduleCache,
};
use chrono_humanize::{Accuracy, HumanTime, Tense};
use crossbeam_channel::Sender;
@ -31,6 +32,7 @@ use solana_runtime::{
};
use solana_sdk::{
clock::{Slot, MAX_PROCESSING_AGE},
feature_set,
genesis_config::GenesisConfig,
hash::Hash,
pubkey::Pubkey,
@ -48,11 +50,40 @@ use std::{
convert::TryFrom,
path::PathBuf,
result,
sync::Arc,
sync::{Arc, RwLock},
time::{Duration, Instant},
};
use thiserror::Error;
// it tracks the block cost available capacity - number of compute-units allowed
// by max blockl cost limit
#[derive(Debug)]
pub struct BlockCostCapacityMeter {
pub capacity: u64,
pub accumulated_cost: u64,
}
impl Default for BlockCostCapacityMeter {
fn default() -> Self {
BlockCostCapacityMeter::new(block_cost_max())
}
}
impl BlockCostCapacityMeter {
pub fn new(capacity_limit: u64) -> Self {
Self {
capacity: capacity_limit,
accumulated_cost: 0_u64,
}
}
// return the remaining capacity
pub fn accumulate(&mut self, cost: u64) -> u64 {
self.accumulated_cost += cost;
self.capacity.saturating_sub(self.accumulated_cost)
}
}
pub type BlockstoreProcessorResult =
result::Result<(BankForks, LeaderScheduleCache), BlockstoreProcessorError>;
@ -100,12 +131,25 @@ fn get_first_error(
first_err
}
fn aggregate_total_execution_units(execute_timings: &ExecuteTimings) -> u64 {
let mut execute_cost_units: u64 = 0;
for (program_id, timing) in &execute_timings.details.per_program_timings {
if timing.count < 1 {
continue;
}
execute_cost_units += timing.accumulated_units / timing.count as u64;
trace!("aggregated execution cost of {:?} {:?}", program_id, timing);
}
execute_cost_units
}
fn execute_batch(
batch: &TransactionBatch,
bank: &Arc<Bank>,
transaction_status_sender: Option<&TransactionStatusSender>,
replay_vote_sender: Option<&ReplayVoteSender>,
timings: &mut ExecuteTimings,
cost_capacity_meter: Arc<RwLock<BlockCostCapacityMeter>>,
) -> Result<()> {
let record_token_balances = transaction_status_sender.is_some();
@ -117,6 +161,8 @@ fn execute_batch(
vec![]
};
let pre_process_units: u64 = aggregate_total_execution_units(timings);
let (tx_results, balances, inner_instructions, transaction_logs) =
batch.bank().load_execute_and_commit_transactions(
batch,
@ -127,6 +173,29 @@ fn execute_batch(
timings,
);
if bank
.feature_set
.is_active(&feature_set::gate_large_block::id())
{
let execution_cost_units = aggregate_total_execution_units(timings) - pre_process_units;
let remaining_block_cost_cap = cost_capacity_meter
.write()
.unwrap()
.accumulate(execution_cost_units);
debug!(
"bank {} executed a batch, number of transactions {}, total execute cu {}, remaining block cost cap {}",
bank.slot(),
batch.sanitized_transactions().len(),
execution_cost_units,
remaining_block_cost_cap,
);
if remaining_block_cost_cap == 0_u64 {
return Err(TransactionError::WouldExceedMaxBlockCostLimit);
}
}
bank_utils::find_and_send_votes(
batch.sanitized_transactions(),
&tx_results,
@ -174,6 +243,7 @@ fn execute_batches(
transaction_status_sender: Option<&TransactionStatusSender>,
replay_vote_sender: Option<&ReplayVoteSender>,
timings: &mut ExecuteTimings,
cost_capacity_meter: Arc<RwLock<BlockCostCapacityMeter>>,
) -> Result<()> {
inc_new_counter_debug!("bank-par_execute_entries-count", batches.len());
let (results, new_timings): (Vec<Result<()>>, Vec<ExecuteTimings>) =
@ -189,6 +259,7 @@ fn execute_batches(
transaction_status_sender,
replay_vote_sender,
&mut timings,
cost_capacity_meter.clone(),
);
if let Some(entry_callback) = entry_callback {
entry_callback(bank);
@ -233,6 +304,7 @@ pub fn process_entries(
transaction_status_sender,
replay_vote_sender,
&mut timings,
Arc::new(RwLock::new(BlockCostCapacityMeter::default())),
);
debug!("process_entries: {:?}", timings);
@ -248,6 +320,7 @@ fn process_entries_with_callback(
transaction_status_sender: Option<&TransactionStatusSender>,
replay_vote_sender: Option<&ReplayVoteSender>,
timings: &mut ExecuteTimings,
cost_capacity_meter: Arc<RwLock<BlockCostCapacityMeter>>,
) -> Result<()> {
// accumulator for entries that can be processed in parallel
let mut batches = vec![];
@ -269,6 +342,7 @@ fn process_entries_with_callback(
transaction_status_sender,
replay_vote_sender,
timings,
cost_capacity_meter.clone(),
)?;
batches.clear();
for hash in &tick_hashes {
@ -320,6 +394,7 @@ fn process_entries_with_callback(
transaction_status_sender,
replay_vote_sender,
timings,
cost_capacity_meter.clone(),
)?;
batches.clear();
}
@ -334,6 +409,7 @@ fn process_entries_with_callback(
transaction_status_sender,
replay_vote_sender,
timings,
cost_capacity_meter,
)?;
for hash in tick_hashes {
bank.register_tick(hash);
@ -820,6 +896,7 @@ pub fn confirm_slot(
let mut replay_elapsed = Measure::start("replay_elapsed");
let mut execute_timings = ExecuteTimings::default();
let cost_capacity_meter = Arc::new(RwLock::new(BlockCostCapacityMeter::default()));
// Note: This will shuffle entries' transactions in-place.
let process_result = process_entries_with_callback(
bank,
@ -829,6 +906,7 @@ pub fn confirm_slot(
transaction_status_sender,
replay_vote_sender,
&mut execute_timings,
cost_capacity_meter,
)
.map_err(BlockstoreProcessorError::from);
replay_elapsed.stop();

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@ -10,6 +10,7 @@ pub mod block_error;
#[macro_use]
pub mod blockstore;
pub mod ancestor_iterator;
pub mod block_cost_limits;
pub mod blockstore_db;
pub mod blockstore_meta;
pub mod blockstore_processor;

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@ -185,7 +185,7 @@ impl ExecuteTimings {
}
type BankStatusCache = StatusCache<Result<()>>;
#[frozen_abi(digest = "HhY4tMP5KZU9fw9VLpMMUikfvNVCLksocZBUKjt8ZjYH")]
#[frozen_abi(digest = "9iDANtGXnSv6WK4vc2rvtrhVMHidKeBM9nQxm34nC79C")]
pub type BankSlotDelta = SlotDelta<Result<()>>;
type TransactionAccountRefCells = Vec<(Pubkey, Rc<RefCell<AccountSharedData>>)>;
type TransactionLoaderRefCells = Vec<Vec<(Pubkey, Rc<RefCell<AccountSharedData>>)>>;

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@ -187,6 +187,10 @@ pub mod stake_merge_with_unmatched_credits_observed {
solana_sdk::declare_id!("meRgp4ArRPhD3KtCY9c5yAf2med7mBLsjKTPeVUHqBL");
}
pub mod gate_large_block {
solana_sdk::declare_id!("2ry7ygxiYURULZCrypHhveanvP5tzZ4toRwVp89oCNSj");
}
lazy_static! {
/// Map of feature identifiers to user-visible description
pub static ref FEATURE_NAMES: HashMap<Pubkey, &'static str> = [
@ -228,6 +232,7 @@ lazy_static! {
(merge_nonce_error_into_system_error::id(), "merge NonceError into SystemError"),
(disable_fees_sysvar::id(), "disable fees sysvar"),
(stake_merge_with_unmatched_credits_observed::id(), "allow merging active stakes with unmatched credits_observed #18985"),
(gate_large_block::id(), "validator checks block cost against max limit in realtime, reject if exceeds."),
/*************** ADD NEW FEATURES HERE ***************/
]
.iter()

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@ -99,6 +99,11 @@ pub enum TransactionError {
/// Transaction processing left an account with an outstanding borrowed reference
#[error("Transaction processing left an account with an outstanding borrowed reference")]
AccountBorrowOutstanding,
#[error(
"Transaction could not fit into current block without exceeding the Max Block Cost Limit"
)]
WouldExceedMaxBlockCostLimit,
}
pub type Result<T> = result::Result<T, TransactionError>;

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@ -41,6 +41,7 @@ enum TransactionErrorType {
SANITIZE_FAILURE = 14;
CLUSTER_MAINTENANCE = 15;
ACCOUNT_BORROW_OUTSTANDING_TX = 16;
WOULD_EXCEED_MAX_BLOCK_COST_LIMIT = 17;
}
message InstructionError {

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@ -606,6 +606,9 @@ impl From<TransactionError> for tx_by_addr::TransactionError {
TransactionError::AccountBorrowOutstanding => {
tx_by_addr::TransactionErrorType::AccountBorrowOutstandingTx
}
TransactionError::WouldExceedMaxBlockCostLimit => {
tx_by_addr::TransactionErrorType::WouldExceedMaxBlockCostLimit
}
} as i32,
instruction_error: match transaction_error {
TransactionError::InstructionError(index, ref instruction_error) => {