514 lines
19 KiB
Rust
514 lines
19 KiB
Rust
//! 'cost_model` provides service to estimate a transaction's cost
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//! It does so by analyzing accounts the transaction touches, and instructions
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//! it includes. Using historical data as guideline, it estimates cost of
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//! reading/writing account, the sum of that comes up to "account access cost";
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//! Instructions take time to execute, both historical and runtime data are
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//! used to determine each instruction's execution time, the sum of that
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//! is transaction's "execution cost"
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//! The main function is `calculate_cost` which returns a TransactionCost struct.
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//!
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use crate::execute_cost_table::ExecuteCostTable;
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use log::*;
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use solana_sdk::{message::Message, pubkey::Pubkey, transaction::Transaction};
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use std::collections::HashMap;
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// Guestimated from mainnet-beta data, sigver averages 1us, read averages 7us and write avergae 25us
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const SIGNED_WRITABLE_ACCOUNT_ACCESS_COST: u64 = 1 + 25;
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const SIGNED_READONLY_ACCOUNT_ACCESS_COST: u64 = 1 + 7;
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const NON_SIGNED_WRITABLE_ACCOUNT_ACCESS_COST: u64 = 25;
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const NON_SIGNED_READONLY_ACCOUNT_ACCESS_COST: u64 = 7;
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// Sampled from mainnet-beta, the instruction execution timings stats are (in us):
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// min=194, max=62164, avg=8214.49, med=2243
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pub const ACCOUNT_MAX_COST: u64 = 100_000_000;
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pub const BLOCK_MAX_COST: u64 = 2_500_000_000;
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// cost of transaction is made of account_access_cost and instruction execution_cost
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// where
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// account_access_cost is the sum of read/write/sign all accounts included in the transaction
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// read is cheaper than write.
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// execution_cost is the sum of all instructions execution cost, which is
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// observed during runtime and feedback by Replay
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#[derive(Default, Debug)]
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pub struct TransactionCost {
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pub writable_accounts: Vec<Pubkey>,
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pub account_access_cost: u64,
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pub execution_cost: u64,
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}
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#[derive(Debug)]
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pub struct CostModel {
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account_cost_limit: u64,
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block_cost_limit: u64,
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instruction_execution_cost_table: ExecuteCostTable,
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}
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impl Default for CostModel {
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fn default() -> Self {
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CostModel::new(ACCOUNT_MAX_COST, BLOCK_MAX_COST)
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}
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}
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impl CostModel {
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pub fn new(chain_max: u64, block_max: u64) -> Self {
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Self {
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account_cost_limit: chain_max,
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block_cost_limit: block_max,
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instruction_execution_cost_table: ExecuteCostTable::default(),
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}
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}
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pub fn get_account_cost_limit(&self) -> u64 {
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self.account_cost_limit
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}
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pub fn get_block_cost_limit(&self) -> u64 {
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self.block_cost_limit
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}
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pub fn calculate_cost(&self, transaction: &Transaction) -> TransactionCost {
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let (
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signed_writable_accounts,
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signed_readonly_accounts,
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non_signed_writable_accounts,
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non_signed_readonly_accounts,
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) = CostModel::sort_accounts_by_type(transaction.message());
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let mut cost = TransactionCost {
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writable_accounts: vec![],
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account_access_cost: CostModel::find_account_access_cost(
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&signed_writable_accounts,
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&signed_readonly_accounts,
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&non_signed_writable_accounts,
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&non_signed_readonly_accounts,
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),
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execution_cost: self.find_transaction_cost(transaction),
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};
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cost.writable_accounts.extend(&signed_writable_accounts);
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cost.writable_accounts.extend(&non_signed_writable_accounts);
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debug!("transaction {:?} has cost {:?}", transaction, cost);
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cost
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}
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// To update or insert instruction cost to table.
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pub fn upsert_instruction_cost(
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&mut self,
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program_key: &Pubkey,
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cost: &u64,
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) -> Result<u64, &'static str> {
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self.instruction_execution_cost_table
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.upsert(program_key, cost);
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match self.instruction_execution_cost_table.get_cost(program_key) {
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Some(cost) => Ok(*cost),
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None => Err("failed to upsert to ExecuteCostTable"),
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}
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}
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pub fn get_instruction_cost_table(&self) -> &HashMap<Pubkey, u64> {
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self.instruction_execution_cost_table.get_cost_table()
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}
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fn find_instruction_cost(&self, program_key: &Pubkey) -> u64 {
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match self.instruction_execution_cost_table.get_cost(program_key) {
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Some(cost) => *cost,
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None => {
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let default_value = self.instruction_execution_cost_table.get_mode();
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debug!(
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"Program key {:?} does not have assigned cost, using mode {}",
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program_key, default_value
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);
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default_value
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}
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}
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}
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fn find_transaction_cost(&self, transaction: &Transaction) -> u64 {
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let mut cost: u64 = 0;
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for instruction in &transaction.message().instructions {
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let program_id =
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transaction.message().account_keys[instruction.program_id_index as usize];
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let instruction_cost = self.find_instruction_cost(&program_id);
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trace!(
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"instruction {:?} has cost of {}",
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instruction,
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instruction_cost
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);
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cost += instruction_cost;
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}
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cost
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}
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fn find_account_access_cost(
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signed_writable_accounts: &[Pubkey],
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signed_readonly_accounts: &[Pubkey],
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non_signed_writable_accounts: &[Pubkey],
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non_signed_readonly_accounts: &[Pubkey],
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) -> u64 {
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let mut cost = 0;
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cost += signed_writable_accounts.len() as u64 * SIGNED_WRITABLE_ACCOUNT_ACCESS_COST;
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cost += signed_readonly_accounts.len() as u64 * SIGNED_READONLY_ACCOUNT_ACCESS_COST;
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cost += non_signed_writable_accounts.len() as u64 * NON_SIGNED_WRITABLE_ACCOUNT_ACCESS_COST;
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cost += non_signed_readonly_accounts.len() as u64 * NON_SIGNED_READONLY_ACCOUNT_ACCESS_COST;
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cost
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}
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fn sort_accounts_by_type(
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message: &Message,
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) -> (Vec<Pubkey>, Vec<Pubkey>, Vec<Pubkey>, Vec<Pubkey>) {
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let demote_sysvar_write_locks = true;
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let mut signer_writable: Vec<Pubkey> = vec![];
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let mut signer_readonly: Vec<Pubkey> = vec![];
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let mut non_signer_writable: Vec<Pubkey> = vec![];
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let mut non_signer_readonly: Vec<Pubkey> = vec![];
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message.account_keys.iter().enumerate().for_each(|(i, k)| {
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let is_signer = message.is_signer(i);
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let is_writable = message.is_writable(i, demote_sysvar_write_locks);
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if is_signer && is_writable {
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signer_writable.push(*k);
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} else if is_signer && !is_writable {
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signer_readonly.push(*k);
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} else if !is_signer && is_writable {
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non_signer_writable.push(*k);
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} else {
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non_signer_readonly.push(*k);
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}
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});
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(
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signer_writable,
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signer_readonly,
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non_signer_writable,
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non_signer_readonly,
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)
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use solana_runtime::{
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bank::Bank,
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genesis_utils::{create_genesis_config, GenesisConfigInfo},
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};
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use solana_sdk::{
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bpf_loader,
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hash::Hash,
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instruction::CompiledInstruction,
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message::Message,
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signature::{Keypair, Signer},
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system_instruction::{self},
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system_program, system_transaction,
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};
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use std::{
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str::FromStr,
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sync::{Arc, RwLock},
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thread::{self, JoinHandle},
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};
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fn test_setup() -> (Keypair, Hash) {
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solana_logger::setup();
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let GenesisConfigInfo {
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genesis_config,
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mint_keypair,
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..
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} = create_genesis_config(10);
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let bank = Arc::new(Bank::new_no_wallclock_throttle(&genesis_config));
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let start_hash = bank.last_blockhash();
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(mint_keypair, start_hash)
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}
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#[test]
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fn test_cost_model_instruction_cost() {
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let mut testee = CostModel::default();
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let known_key = Pubkey::from_str("known11111111111111111111111111111111111111").unwrap();
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testee.upsert_instruction_cost(&known_key, &100).unwrap();
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// find cost for known programs
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assert_eq!(100, testee.find_instruction_cost(&known_key));
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testee
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.upsert_instruction_cost(&bpf_loader::id(), &1999)
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.unwrap();
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assert_eq!(1999, testee.find_instruction_cost(&bpf_loader::id()));
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// unknown program is assigned with default cost
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assert_eq!(
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testee.instruction_execution_cost_table.get_mode(),
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testee.find_instruction_cost(
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&Pubkey::from_str("unknown111111111111111111111111111111111111").unwrap()
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)
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);
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}
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#[test]
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fn test_cost_model_simple_transaction() {
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let (mint_keypair, start_hash) = test_setup();
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let keypair = Keypair::new();
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let simple_transaction =
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system_transaction::transfer(&mint_keypair, &keypair.pubkey(), 2, start_hash);
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debug!(
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"system_transaction simple_transaction {:?}",
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simple_transaction
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);
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// expected cost for one system transfer instructions
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let expected_cost = 8;
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let mut testee = CostModel::default();
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testee
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.upsert_instruction_cost(&system_program::id(), &expected_cost)
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.unwrap();
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assert_eq!(
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expected_cost,
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testee.find_transaction_cost(&simple_transaction)
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);
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}
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#[test]
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fn test_cost_model_transaction_many_transfer_instructions() {
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let (mint_keypair, start_hash) = test_setup();
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let key1 = solana_sdk::pubkey::new_rand();
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let key2 = solana_sdk::pubkey::new_rand();
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let instructions =
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system_instruction::transfer_many(&mint_keypair.pubkey(), &[(key1, 1), (key2, 1)]);
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let message = Message::new(&instructions, Some(&mint_keypair.pubkey()));
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let tx = Transaction::new(&[&mint_keypair], message, start_hash);
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debug!("many transfer transaction {:?}", tx);
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// expected cost for two system transfer instructions
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let program_cost = 8;
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let expected_cost = program_cost * 2;
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let mut testee = CostModel::default();
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testee
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.upsert_instruction_cost(&system_program::id(), &program_cost)
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.unwrap();
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assert_eq!(expected_cost, testee.find_transaction_cost(&tx));
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}
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#[test]
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fn test_cost_model_message_many_different_instructions() {
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let (mint_keypair, start_hash) = test_setup();
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// construct a transaction with multiple random instructions
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let key1 = solana_sdk::pubkey::new_rand();
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let key2 = solana_sdk::pubkey::new_rand();
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let prog1 = solana_sdk::pubkey::new_rand();
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let prog2 = solana_sdk::pubkey::new_rand();
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let instructions = vec![
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CompiledInstruction::new(3, &(), vec![0, 1]),
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CompiledInstruction::new(4, &(), vec![0, 2]),
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];
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let tx = Transaction::new_with_compiled_instructions(
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&[&mint_keypair],
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&[key1, key2],
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start_hash,
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vec![prog1, prog2],
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instructions,
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);
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debug!("many random transaction {:?}", tx);
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let testee = CostModel::default();
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let result = testee.find_transaction_cost(&tx);
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// expected cost for two random/unknown program is
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let expected_cost = testee.instruction_execution_cost_table.get_mode() * 2;
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assert_eq!(expected_cost, result);
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}
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#[test]
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fn test_cost_model_sort_message_accounts_by_type() {
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// construct a transaction with two random instructions with same signer
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let signer1 = Keypair::new();
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let signer2 = Keypair::new();
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let key1 = Pubkey::new_unique();
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let key2 = Pubkey::new_unique();
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let prog1 = Pubkey::new_unique();
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let prog2 = Pubkey::new_unique();
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let instructions = vec![
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CompiledInstruction::new(4, &(), vec![0, 2]),
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CompiledInstruction::new(5, &(), vec![1, 3]),
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];
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let tx = Transaction::new_with_compiled_instructions(
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&[&signer1, &signer2],
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&[key1, key2],
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Hash::new_unique(),
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vec![prog1, prog2],
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instructions,
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);
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debug!("many random transaction {:?}", tx);
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let (
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signed_writable_accounts,
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signed_readonly_accounts,
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non_signed_writable_accounts,
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non_signed_readonly_accounts,
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) = CostModel::sort_accounts_by_type(tx.message());
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assert_eq!(2, signed_writable_accounts.len());
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assert_eq!(signer1.pubkey(), signed_writable_accounts[0]);
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assert_eq!(signer2.pubkey(), signed_writable_accounts[1]);
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assert_eq!(0, signed_readonly_accounts.len());
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assert_eq!(2, non_signed_writable_accounts.len());
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assert_eq!(key1, non_signed_writable_accounts[0]);
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assert_eq!(key2, non_signed_writable_accounts[1]);
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assert_eq!(2, non_signed_readonly_accounts.len());
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assert_eq!(prog1, non_signed_readonly_accounts[0]);
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assert_eq!(prog2, non_signed_readonly_accounts[1]);
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}
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#[test]
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fn test_cost_model_insert_instruction_cost() {
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let key1 = Pubkey::new_unique();
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let cost1 = 100;
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let mut cost_model = CostModel::default();
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// Using default cost for unknown instruction
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assert_eq!(
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cost_model.instruction_execution_cost_table.get_mode(),
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cost_model.find_instruction_cost(&key1)
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);
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// insert instruction cost to table
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assert!(cost_model.upsert_instruction_cost(&key1, &cost1).is_ok());
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// now it is known insturction with known cost
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assert_eq!(cost1, cost_model.find_instruction_cost(&key1));
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}
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#[test]
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fn test_cost_model_calculate_cost() {
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let (mint_keypair, start_hash) = test_setup();
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let tx =
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system_transaction::transfer(&mint_keypair, &Keypair::new().pubkey(), 2, start_hash);
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let expected_account_cost = SIGNED_WRITABLE_ACCOUNT_ACCESS_COST
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+ NON_SIGNED_WRITABLE_ACCOUNT_ACCESS_COST
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+ NON_SIGNED_READONLY_ACCOUNT_ACCESS_COST;
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let expected_execution_cost = 8;
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let mut cost_model = CostModel::default();
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cost_model
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.upsert_instruction_cost(&system_program::id(), &expected_execution_cost)
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.unwrap();
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let tx_cost = cost_model.calculate_cost(&tx);
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assert_eq!(expected_account_cost, tx_cost.account_access_cost);
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assert_eq!(expected_execution_cost, tx_cost.execution_cost);
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assert_eq!(2, tx_cost.writable_accounts.len());
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}
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#[test]
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fn test_cost_model_update_instruction_cost() {
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let key1 = Pubkey::new_unique();
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let cost1 = 100;
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let cost2 = 200;
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let updated_cost = (cost1 + cost2) / 2;
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let mut cost_model = CostModel::default();
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// insert instruction cost to table
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assert!(cost_model.upsert_instruction_cost(&key1, &cost1).is_ok());
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assert_eq!(cost1, cost_model.find_instruction_cost(&key1));
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// update instruction cost
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assert!(cost_model.upsert_instruction_cost(&key1, &cost2).is_ok());
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assert_eq!(updated_cost, cost_model.find_instruction_cost(&key1));
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}
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#[test]
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fn test_cost_model_can_be_shared_concurrently_as_immutable() {
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let (mint_keypair, start_hash) = test_setup();
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let number_threads = 10;
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let expected_account_cost = SIGNED_WRITABLE_ACCOUNT_ACCESS_COST
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+ NON_SIGNED_WRITABLE_ACCOUNT_ACCESS_COST
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+ NON_SIGNED_READONLY_ACCOUNT_ACCESS_COST;
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let cost_model = Arc::new(CostModel::default());
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let thread_handlers: Vec<JoinHandle<()>> = (0..number_threads)
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.map(|_| {
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// each thread creates its own simple transaction
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let simple_transaction = system_transaction::transfer(
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&mint_keypair,
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&Keypair::new().pubkey(),
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2,
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start_hash,
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);
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let cost_model = cost_model.clone();
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thread::spawn(move || {
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let tx_cost = cost_model.calculate_cost(&simple_transaction);
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assert_eq!(2, tx_cost.writable_accounts.len());
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assert_eq!(expected_account_cost, tx_cost.account_access_cost);
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assert_eq!(
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cost_model.instruction_execution_cost_table.get_mode(),
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tx_cost.execution_cost
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);
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})
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})
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.collect();
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for th in thread_handlers {
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th.join().unwrap();
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}
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}
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#[test]
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fn test_cost_model_can_be_shared_concurrently_with_rwlock() {
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let (mint_keypair, start_hash) = test_setup();
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// construct a transaction with multiple random instructions
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let key1 = solana_sdk::pubkey::new_rand();
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let key2 = solana_sdk::pubkey::new_rand();
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let prog1 = solana_sdk::pubkey::new_rand();
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let prog2 = solana_sdk::pubkey::new_rand();
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let instructions = vec![
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CompiledInstruction::new(3, &(), vec![0, 1]),
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CompiledInstruction::new(4, &(), vec![0, 2]),
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];
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let tx = Arc::new(Transaction::new_with_compiled_instructions(
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&[&mint_keypair],
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&[key1, key2],
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start_hash,
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vec![prog1, prog2],
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instructions,
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));
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let number_threads = 10;
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let expected_account_cost = SIGNED_WRITABLE_ACCOUNT_ACCESS_COST
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+ NON_SIGNED_WRITABLE_ACCOUNT_ACCESS_COST * 2
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+ NON_SIGNED_READONLY_ACCOUNT_ACCESS_COST * 2;
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let cost1 = 100;
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let cost2 = 200;
|
|
// execution cost can be either 2 * Default (before write) or cost1+cost2 (after write)
|
|
|
|
let cost_model: Arc<RwLock<CostModel>> = Arc::new(RwLock::new(CostModel::default()));
|
|
|
|
let thread_handlers: Vec<JoinHandle<()>> = (0..number_threads)
|
|
.map(|i| {
|
|
let cost_model = cost_model.clone();
|
|
let tx = tx.clone();
|
|
|
|
if i == 5 {
|
|
thread::spawn(move || {
|
|
let mut cost_model = cost_model.write().unwrap();
|
|
assert!(cost_model.upsert_instruction_cost(&prog1, &cost1).is_ok());
|
|
assert!(cost_model.upsert_instruction_cost(&prog2, &cost2).is_ok());
|
|
})
|
|
} else {
|
|
thread::spawn(move || {
|
|
let tx_cost = cost_model.read().unwrap().calculate_cost(&tx);
|
|
assert_eq!(3, tx_cost.writable_accounts.len());
|
|
assert_eq!(expected_account_cost, tx_cost.account_access_cost);
|
|
})
|
|
}
|
|
})
|
|
.collect();
|
|
|
|
for th in thread_handlers {
|
|
th.join().unwrap();
|
|
}
|
|
}
|
|
}
|