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Move EpochRewardsHasher to solana-sdk (#34934)
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* Move EpochRewardsHasher to solana-sdk

* Cargo.lock

* Apparently we're allowing arithmetic_side_effects in all of runtime

* Move allow stmt to block instead of module

* Also allow in test mod
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Tyera authored Jan 24, 2024
1 parent 3004eaa commit bbd1fd4
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Showing 7 changed files with 192 additions and 183 deletions.
2 changes: 1 addition & 1 deletion Cargo.lock
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2 changes: 1 addition & 1 deletion programs/sbf/Cargo.lock
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1 change: 0 additions & 1 deletion runtime/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,6 @@ regex = { workspace = true }
serde = { workspace = true, features = ["rc"] }
serde_derive = { workspace = true }
serde_json = { workspace = true }
siphasher = { workspace = true }
solana-accounts-db = { workspace = true }
solana-address-lookup-table-program = { workspace = true }
solana-bpf-loader-program = { workspace = true }
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182 changes: 2 additions & 180 deletions runtime/src/epoch_rewards_hasher.rs
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Original file line number Diff line number Diff line change
@@ -1,45 +1,8 @@
use {
crate::bank::StakeRewards,
siphasher::sip::SipHasher13,
solana_sdk::{hash::Hash, pubkey::Pubkey},
std::hash::Hasher,
solana_sdk::{epoch_rewards_hasher::EpochRewardsHasher, hash::Hash},
};

#[derive(Debug, Clone)]
pub(crate) struct EpochRewardsHasher {
hasher: SipHasher13,
partitions: usize,
}

impl EpochRewardsHasher {
/// Use SipHasher13 keyed on the `seed` for calculating epoch reward partition
pub(crate) fn new(partitions: usize, seed: &Hash) -> Self {
let mut hasher = SipHasher13::new();
hasher.write(seed.as_ref());
Self { hasher, partitions }
}

/// Return partition index (0..partitions) by hashing `address` with the `hasher`
pub(crate) fn hash_address_to_partition(self, address: &Pubkey) -> usize {
let Self {
mut hasher,
partitions,
} = self;
hasher.write(address.as_ref());
let hash64 = hasher.finish();

hash_to_partition(hash64, partitions)
}
}

/// Compute the partition index by modulo the address hash to number of partitions w.o bias.
/// (rand_int * DESIRED_RANGE_MAX) / (RAND_MAX + 1)
fn hash_to_partition(hash: u64, partitions: usize) -> usize {
((partitions as u128)
.saturating_mul(u128::from(hash))
.saturating_div(u128::from(u64::MAX).saturating_add(1))) as usize
}

pub(crate) fn hash_rewards_into_partitions(
stake_rewards: StakeRewards,
parent_blockhash: &Hash,
Expand All @@ -62,148 +25,7 @@ pub(crate) fn hash_rewards_into_partitions(

#[cfg(test)]
mod tests {
use {
super::*,
solana_accounts_db::stake_rewards::StakeReward,
std::{collections::HashMap, ops::RangeInclusive},
};

#[test]
fn test_get_equal_partition_range() {
// show how 2 equal partition ranges are 0..=(max/2), (max/2+1)..=max
// the inclusive is tricky to think about
let range = get_equal_partition_range(0, 2);
assert_eq!(*range.start(), 0);
assert_eq!(*range.end(), u64::MAX / 2);
let range = get_equal_partition_range(1, 2);
assert_eq!(*range.start(), u64::MAX / 2 + 1);
assert_eq!(*range.end(), u64::MAX);
}

#[test]
fn test_hash_to_partitions() {
let partitions = 16;
assert_eq!(hash_to_partition(0, partitions), 0);
assert_eq!(hash_to_partition(u64::MAX / 16, partitions), 0);
assert_eq!(hash_to_partition(u64::MAX / 16 + 1, partitions), 1);
assert_eq!(hash_to_partition(u64::MAX / 16 * 2, partitions), 1);
assert_eq!(hash_to_partition(u64::MAX / 16 * 2 + 1, partitions), 1);
assert_eq!(hash_to_partition(u64::MAX - 1, partitions), partitions - 1);
assert_eq!(hash_to_partition(u64::MAX, partitions), partitions - 1);
}

fn test_partitions(partition: usize, partitions: usize) {
let partition = partition.min(partitions - 1);
let range = get_equal_partition_range(partition, partitions);
// beginning and end of this partition
assert_eq!(hash_to_partition(*range.start(), partitions), partition);
assert_eq!(hash_to_partition(*range.end(), partitions), partition);
if partition < partitions - 1 {
// first index in next partition
assert_eq!(
hash_to_partition(*range.end() + 1, partitions),
partition + 1
);
} else {
assert_eq!(*range.end(), u64::MAX);
}
if partition > 0 {
// last index in previous partition
assert_eq!(
hash_to_partition(*range.start() - 1, partitions),
partition - 1
);
} else {
assert_eq!(*range.start(), 0);
}
}

#[test]
fn test_hash_to_partitions_equal_ranges() {
for partitions in [2, 4, 8, 16, 4096] {
assert_eq!(hash_to_partition(0, partitions), 0);
for partition in [0, 1, 2, partitions - 1] {
test_partitions(partition, partitions);
}

let range = get_equal_partition_range(0, partitions);
for partition in 1..partitions {
let this_range = get_equal_partition_range(partition, partitions);
assert_eq!(
this_range.end() - this_range.start(),
range.end() - range.start()
);
}
}
// verify non-evenly divisible partitions (partitions will be different sizes by at most 1 from any other partition)
for partitions in [3, 19, 1019, 4095] {
for partition in [0, 1, 2, partitions - 1] {
test_partitions(partition, partitions);
}
let expected_len_of_partition =
((u128::from(u64::MAX) + 1) / partitions as u128) as u64;
for partition in 0..partitions {
let this_range = get_equal_partition_range(partition, partitions);
let len = this_range.end() - this_range.start();
// size is same or 1 less
assert!(
len == expected_len_of_partition || len + 1 == expected_len_of_partition,
"{}, {}, {}, {}",
expected_len_of_partition,
len,
partition,
partitions
);
}
}
}

/// return start and end_inclusive of `partition` indexes out of from u64::MAX+1 elements in equal `partitions`
/// These will be equal as long as (u64::MAX + 1) divides by `partitions` evenly
fn get_equal_partition_range(partition: usize, partitions: usize) -> RangeInclusive<u64> {
let max_inclusive = u128::from(u64::MAX);
let max_plus_1 = max_inclusive + 1;
let partition = partition as u128;
let partitions = partitions as u128;
let mut start = max_plus_1 * partition / partitions;
if partition > 0 && start * partitions / max_plus_1 == partition - 1 {
// partitions don't evenly divide and the start of this partition needs to be 1 greater
start += 1;
}

let mut end_inclusive = start + max_plus_1 / partitions - 1;
if partition < partitions.saturating_sub(1) {
let next = end_inclusive + 1;
if next * partitions / max_plus_1 == partition {
// this partition is far enough into partitions such that the len of this partition is 1 larger than expected
end_inclusive += 1;
}
} else {
end_inclusive = max_inclusive;
}
RangeInclusive::new(start as u64, end_inclusive as u64)
}

/// Make sure that each time hash_address_to_partition is called, it uses the initial seed state and that clone correctly copies the initial hasher state.
#[test]
fn test_hasher_copy() {
let seed = Hash::new_unique();
let partitions = 10;
let hasher = EpochRewardsHasher::new(partitions, &seed);

let pk = Pubkey::new_unique();

let b1 = hasher.clone().hash_address_to_partition(&pk);
let b2 = hasher.hash_address_to_partition(&pk);
assert_eq!(b1, b2);

// make sure b1 includes the seed's hash
let mut hasher = SipHasher13::new();
hasher.write(seed.as_ref());
hasher.write(pk.as_ref());
let partition = hash_to_partition(hasher.finish(), partitions);
assert_eq!(partition, b1);
}
use {super::*, solana_accounts_db::stake_rewards::StakeReward, std::collections::HashMap};

#[test]
fn test_hash_rewards_into_partitions() {
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1 change: 1 addition & 0 deletions sdk/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -75,6 +75,7 @@ serde_json = { workspace = true, optional = true }
serde_with = { workspace = true, features = ["macros"] }
sha2 = { workspace = true }
sha3 = { workspace = true, optional = true }
siphasher = { workspace = true }
solana-frozen-abi = { workspace = true }
solana-frozen-abi-macro = { workspace = true }
solana-logger = { workspace = true, optional = true }
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