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pallet-offences-benchmarking: Box events in verify (paritytech#13151)
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* pallet-offences-benchmarking: Box events in verify

Events in frame are represented by an enum in the pallet and the runtime. The size of an enum in
Rust depends on the size of biggest variant. This means we always need to allocate memory for the
biggest variant when allocating memory for an event. The offences benchmarking is verifying the
benchmarking results by checking the events. To check the events it is generating all the expected
events. With the recent changes in Polkadot the events are too big and lead to issues when running
this verify functions. The solution is to box each event, as the vector holding all the events will
then only need to hold fat pointers * expected events, instead of size_of(event) * expected events.
This issue isn't a problem in production, as we never read the events on chain. When we are reading
the events, it is done in an offchain context and they are only decoded one by one.

Besides that this also enables the benchmarking verification for everyone running these benchmarks.

* FMT

* Disable checking again
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@bkchr @ltfschoen
bkchr authored and ltfschoen committed Feb 22, 2023
1 parent e7a5d00 commit 1540e4c
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1 change: 1 addition & 0 deletions Cargo.lock
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2 changes: 2 additions & 0 deletions frame/offences/benchmarking/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@ pallet-staking = { version = "4.0.0-dev", default-features = false, path = "../.
sp-runtime = { version = "7.0.0", default-features = false, path = "../../../primitives/runtime" }
sp-staking = { version = "4.0.0-dev", default-features = false, path = "../../../primitives/staking" }
sp-std = { version = "5.0.0", default-features = false, path = "../../../primitives/std" }
log = { version = "0.4.17", default-features = false }

[dev-dependencies]
pallet-staking-reward-curve = { version = "4.0.0-dev", path = "../../staking/reward-curve" }
Expand All @@ -55,6 +56,7 @@ std = [
"sp-runtime/std",
"sp-staking/std",
"sp-std/std",
"log/std",
]

runtime-benchmarks = [
Expand Down
189 changes: 101 additions & 88 deletions frame/offences/benchmarking/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -28,8 +28,10 @@ use frame_benchmarking::{account, benchmarks};
use frame_support::traits::{Currency, Get, ValidatorSet, ValidatorSetWithIdentification};
use frame_system::{Config as SystemConfig, Pallet as System, RawOrigin};

#[cfg(test)]
use sp_runtime::traits::UniqueSaturatedInto;
use sp_runtime::{
traits::{Convert, Saturating, StaticLookup, UniqueSaturatedInto},
traits::{Convert, Saturating, StaticLookup},
Perbill,
};
use sp_staking::offence::{Offence, ReportOffence};
Expand All @@ -43,9 +45,11 @@ use pallet_session::{
historical::{Config as HistoricalConfig, IdentificationTuple},
Config as SessionConfig, SessionManager,
};
#[cfg(test)]
use pallet_staking::Event as StakingEvent;
use pallet_staking::{
Config as StakingConfig, Event as StakingEvent, Exposure, IndividualExposure,
Pallet as Staking, RewardDestination, ValidatorPrefs,
Config as StakingConfig, Exposure, IndividualExposure, Pallet as Staking, RewardDestination,
ValidatorPrefs,
};

const SEED: u32 = 0;
Expand Down Expand Up @@ -89,7 +93,9 @@ type BalanceOf<T> =

struct Offender<T: Config> {
pub controller: T::AccountId,
#[allow(dead_code)]
pub stash: T::AccountId,
#[allow(dead_code)]
pub nominator_stashes: Vec<T::AccountId>,
}

Expand Down Expand Up @@ -217,55 +223,63 @@ fn make_offenders_im_online<T: Config>(
}

#[cfg(test)]
fn check_events<T: Config, I: Iterator<Item = <T as SystemConfig>::RuntimeEvent>>(expected: I) {
fn check_events<
T: Config,
I: Iterator<Item = Item>,
Item: sp_std::borrow::Borrow<<T as SystemConfig>::RuntimeEvent> + sp_std::fmt::Debug,
>(
expected: I,
) {
let events = System::<T>::events()
.into_iter()
.map(|frame_system::EventRecord { event, .. }| event)
.collect::<Vec<_>>();
let expected = expected.collect::<Vec<_>>();

fn pretty<D: std::fmt::Debug>(header: &str, ev: &[D], offset: usize) {
println!("{}", header);
fn pretty<D: sp_std::fmt::Debug>(header: &str, ev: &[D], offset: usize) {
log::info!("{}", header);
for (idx, ev) in ev.iter().enumerate() {
println!("\t[{:04}] {:?}", idx + offset, ev);
log::info!("\t[{:04}] {:?}", idx + offset, ev);
}
}
fn print_events<D: std::fmt::Debug>(idx: usize, events: &[D], expected: &[D]) {
fn print_events<D: sp_std::fmt::Debug, E: sp_std::fmt::Debug>(
idx: usize,
events: &[D],
expected: &[E],
) {
let window = 10;
let start = idx.saturating_sub(window / 2);
let end_got = (idx + window / 2).min(events.len());
pretty("Got(window):", &events[start..end_got], start);
let end_expected = (idx + window / 2).min(expected.len());
pretty("Expected(window):", &expected[start..end_expected], start);
println!("---------------");
log::info!("---------------");
let start_got = events.len().saturating_sub(window);
pretty("Got(end):", &events[start_got..], start_got);
let start_expected = expected.len().saturating_sub(window);
pretty("Expected(end):", &expected[start_expected..], start_expected);
}
let events_copy = events.clone();
let expected_copy = expected.clone();

for (idx, (a, b)) in events.into_iter().zip(expected).enumerate() {
if a != b {
print_events(idx, &events_copy, &expected_copy);
println!("Mismatch at: {}", idx);
println!(" Got: {:?}", b);
println!("Expected: {:?}", a);
if events_copy.len() != expected_copy.len() {
println!(

for (idx, (a, b)) in events.iter().zip(expected.iter()).enumerate() {
if a != sp_std::borrow::Borrow::borrow(b) {
print_events(idx, &events, &expected);
log::info!("Mismatch at: {}", idx);
log::info!(" Got: {:?}", b);
log::info!("Expected: {:?}", a);
if events.len() != expected.len() {
log::info!(
"Mismatching lengths. Got: {}, Expected: {}",
events_copy.len(),
expected_copy.len()
events.len(),
expected.len()
)
}
panic!("Mismatching events.");
}
}

if events_copy.len() != expected_copy.len() {
print_events(0, &events_copy, &expected_copy);
panic!("Mismatching lengths. Got: {}, Expected: {}", events_copy.len(), expected_copy.len())
if events.len() != expected.len() {
print_events(0, &events, &expected);
panic!("Mismatching lengths. Got: {}, Expected: {}", events.len(), expected.len(),)
}
}

Expand Down Expand Up @@ -304,79 +318,78 @@ benchmarks! {
);
}
verify {
let bond_amount: u32 = UniqueSaturatedInto::<u32>::unique_saturated_into(bond_amount::<T>());
let slash_amount = slash_fraction * bond_amount;
let reward_amount = slash_amount.saturating_mul(1 + n) / 2;
let reward = reward_amount / r;
let slash_report = |id| core::iter::once(
<T as StakingConfig>::RuntimeEvent::from(StakingEvent::<T>::SlashReported{ validator: id, fraction: slash_fraction, slash_era: 0})
);
let slash = |id| core::iter::once(
<T as StakingConfig>::RuntimeEvent::from(StakingEvent::<T>::Slashed{ staker: id, amount: BalanceOf::<T>::from(slash_amount) })
);
let balance_slash = |id| core::iter::once(
<T as BalancesConfig>::RuntimeEvent::from(pallet_balances::Event::<T>::Slashed{ who: id, amount: slash_amount.into() })
);
let chill = |id| core::iter::once(
<T as StakingConfig>::RuntimeEvent::from(StakingEvent::<T>::Chilled{ stash: id })
);
let balance_deposit = |id, amount: u32|
#[cfg(test)]
{
let bond_amount: u32 = UniqueSaturatedInto::<u32>::unique_saturated_into(bond_amount::<T>());
let slash_amount = slash_fraction * bond_amount;
let reward_amount = slash_amount.saturating_mul(1 + n) / 2;
let reward = reward_amount / r;
let slash_report = |id| core::iter::once(
<T as StakingConfig>::RuntimeEvent::from(StakingEvent::<T>::SlashReported{ validator: id, fraction: slash_fraction, slash_era: 0})
);
let slash = |id| core::iter::once(
<T as StakingConfig>::RuntimeEvent::from(StakingEvent::<T>::Slashed{ staker: id, amount: BalanceOf::<T>::from(slash_amount) })
);
let balance_slash = |id| core::iter::once(
<T as BalancesConfig>::RuntimeEvent::from(pallet_balances::Event::<T>::Slashed{ who: id, amount: slash_amount.into() })
);
let chill = |id| core::iter::once(
<T as StakingConfig>::RuntimeEvent::from(StakingEvent::<T>::Chilled{ stash: id })
);
let balance_deposit = |id, amount: u32|
<T as BalancesConfig>::RuntimeEvent::from(pallet_balances::Event::<T>::Deposit{ who: id, amount: amount.into() });
let mut first = true;
let slash_events = raw_offenders.into_iter()
.flat_map(|offender| {
let nom_slashes = offender.nominator_stashes.into_iter().flat_map(|nom| {
balance_slash(nom.clone()).map(Into::into)
.chain(slash(nom).map(Into::into))
});

let mut events = chill(offender.stash.clone()).map(Into::into)
.chain(slash_report(offender.stash.clone()).map(Into::into))
.chain(balance_slash(offender.stash.clone()).map(Into::into))
.chain(slash(offender.stash).map(Into::into))
.chain(nom_slashes)
.collect::<Vec<_>>();

// the first deposit creates endowed events, see `endowed_reward_events`
if first {
first = false;
let mut reward_events = reporters.clone().into_iter()
.flat_map(|reporter| vec![
balance_deposit(reporter.clone(), reward).into(),
frame_system::Event::<T>::NewAccount { account: reporter.clone() }.into(),
<T as BalancesConfig>::RuntimeEvent::from(
pallet_balances::Event::<T>::Endowed{account: reporter, free_balance: reward.into()}
).into(),
])
let mut first = true;

// We need to box all events to prevent running into too big allocations in wasm.
// The event in FRAME is represented as an enum and the size of the enum depends on the biggest variant.
// So, instead of requiring `size_of<Event>() * expected_events` we only need to
// allocate `size_of<Box<Event>>() * expected_events`.
let slash_events = raw_offenders.into_iter()
.flat_map(|offender| {
let nom_slashes = offender.nominator_stashes.into_iter().flat_map(|nom| {
balance_slash(nom.clone()).map(Into::into).chain(slash(nom).map(Into::into)).map(Box::new)
});

let events = chill(offender.stash.clone()).map(Into::into).map(Box::new)
.chain(slash_report(offender.stash.clone()).map(Into::into).map(Box::new))
.chain(balance_slash(offender.stash.clone()).map(Into::into).map(Box::new))
.chain(slash(offender.stash).map(Into::into).map(Box::new))
.chain(nom_slashes)
.collect::<Vec<_>>();
events.append(&mut reward_events);
events.into_iter()
} else {
let mut reward_events = reporters.clone().into_iter()
.map(|reporter| balance_deposit(reporter, reward).into())
.collect::<Vec<_>>();
events.append(&mut reward_events);
events.into_iter()
}
})
.collect::<Vec<_>>();


// the first deposit creates endowed events, see `endowed_reward_events`
if first {
first = false;
let reward_events = reporters.iter()
.flat_map(|reporter| vec![
Box::new(balance_deposit(reporter.clone(), reward).into()),
Box::new(frame_system::Event::<T>::NewAccount { account: reporter.clone() }.into()),
Box::new(<T as BalancesConfig>::RuntimeEvent::from(
pallet_balances::Event::<T>::Endowed{ account: reporter.clone(), free_balance: reward.into() }
).into()),
])
.collect::<Vec<_>>();
events.into_iter().chain(reward_events)
} else {
let reward_events = reporters.iter()
.map(|reporter| Box::new(balance_deposit(reporter.clone(), reward).into()))
.collect::<Vec<_>>();
events.into_iter().chain(reward_events)
}
});

#[cfg(test)]
{
// In case of error it's useful to see the inputs
println!("Inputs: r: {}, o: {}, n: {}", r, o, n);
log::info!("Inputs: r: {}, o: {}, n: {}", r, o, n);
// make sure that all slashes have been applied
check_events::<T, _>(
std::iter::empty()
.chain(slash_events.into_iter().map(Into::into))
.chain(std::iter::once(<T as OffencesConfig>::RuntimeEvent::from(
check_events::<T, _, _>(
sp_std::iter::empty()
.chain(slash_events)
.chain(sp_std::iter::once(Box::new(<T as OffencesConfig>::RuntimeEvent::from(
pallet_offences::Event::Offence{
kind: UnresponsivenessOffence::<T>::ID,
timeslot: 0_u32.to_le_bytes().to_vec(),
}
).into()))
).into())))
);
}
}
Expand Down

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