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removes legacy weighted_shuffle and weighted_best methods (#24125)

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Older weighted_shuffle is based on a heuristic which results in biased
samples as shown in:
https://github.com/solana-labs/solana/pull/18343
and can be replaced with WeightedShuffle.

Also, as described in:
https://github.com/solana-labs/solana/pull/13919
weighted_best can be replaced with rand::distributions::WeightedIndex,
or WeightdShuffle::first.
This commit is contained in:
behzad nouri
2022-04-05 19:19:22 +00:00
committed by GitHub
parent 4ea59d8cb4
commit db23295e1c
4 changed files with 33 additions and 163 deletions
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27
core/src/serve_repair.rs
View File

@ -17,7 +17,7 @@ use {
solana_gossip::{
cluster_info::{ClusterInfo, ClusterInfoError},
contact_info::ContactInfo,
weighted_shuffle::{weighted_best, weighted_shuffle},
weighted_shuffle::WeightedShuffle,
},
solana_ledger::{
ancestor_iterator::{AncestorIterator, AncestorIteratorWithHash},
@ -525,16 +525,17 @@ impl ServeRepair {
if repair_peers.is_empty() {
return Err(ClusterInfoError::NoPeers.into());
}
let weights = cluster_slots.compute_weights_exclude_nonfrozen(slot, &repair_peers);
let mut sampled_validators = weighted_shuffle(
weights.into_iter().map(|(stake, _i)| stake),
solana_sdk::pubkey::new_rand().to_bytes(),
);
sampled_validators.truncate(ANCESTOR_HASH_REPAIR_SAMPLE_SIZE);
Ok(sampled_validators
let (weights, index): (Vec<_>, Vec<_>) = cluster_slots
.compute_weights_exclude_nonfrozen(slot, &repair_peers)
.into_iter()
.unzip();
let peers = WeightedShuffle::new("repair_request_ancestor_hashes", &weights)
.shuffle(&mut rand::thread_rng())
.take(ANCESTOR_HASH_REPAIR_SAMPLE_SIZE)
.map(|i| index[i])
.map(|i| (repair_peers[i].id, repair_peers[i].serve_repair))
.collect())
.collect();
Ok(peers)
}
pub fn repair_request_duplicate_compute_best_peer(
@ -547,8 +548,12 @@ impl ServeRepair {
if repair_peers.is_empty() {
return Err(ClusterInfoError::NoPeers.into());
}
let weights = cluster_slots.compute_weights_exclude_nonfrozen(slot, &repair_peers);
let n = weighted_best(&weights, solana_sdk::pubkey::new_rand().to_bytes());
let (weights, index): (Vec<_>, Vec<_>) = cluster_slots
.compute_weights_exclude_nonfrozen(slot, &repair_peers)
.into_iter()
.unzip();
let k = WeightedIndex::new(weights)?.sample(&mut rand::thread_rng());
let n = index[k];
Ok((repair_peers[n].id, repair_peers[n].serve_repair))
}