gossip: reduce votes stored per validator from 32 to 12 (anza-xyz#3315)

Author: AshwinSekar

gossip/src/cluster_info.rs

@@ -18,7 +18,7 @@ use {
         cluster_info_metrics::{Counter, GossipStats, ScopedTimer, TimedGuard},
         contact_info::{self, ContactInfo, ContactInfoQuery, Error as ContactInfoError},
         crds::{Crds, Cursor, GossipRoute},
-        crds_data::{self, CrdsData, EpochSlotsIndex, LowestSlot, SnapshotHashes, Vote},
+        crds_data::{self, CrdsData, EpochSlotsIndex, LowestSlot, SnapshotHashes, Vote, MAX_VOTES},
         crds_gossip::CrdsGossip,
         crds_gossip_error::CrdsGossipError,
         crds_gossip_pull::{
@@ -76,7 +76,6 @@ use {
     solana_time_utils::timestamp,
     solana_transaction::Transaction,
     solana_vote::vote_parser,
-    solana_vote_program::vote_state::MAX_LOCKOUT_HISTORY,
     std::{
         borrow::Borrow,
         collections::{HashMap, HashSet, VecDeque},
@@ -786,7 +785,7 @@ impl ClusterInfo {
     }
 
     pub fn push_vote_at_index(&self, vote: Transaction, vote_index: u8) {
-        assert!((vote_index as usize) < MAX_LOCKOUT_HISTORY);
+        assert!(vote_index < MAX_VOTES);
         let self_pubkey = self.id();
         let now = timestamp();
         let vote = Vote::new(self_pubkey, vote, now).unwrap();
@@ -812,7 +811,7 @@ impl ClusterInfo {
         let vote_index = {
             let gossip_crds =
                 self.time_gossip_read_lock("gossip_read_push_vote", &self.stats.push_vote_read);
-            (0..MAX_LOCKOUT_HISTORY as u8)
+            (0..MAX_VOTES)
                 .filter_map(|ix| {
                     let vote = CrdsValueLabel::Vote(ix, self_pubkey);
                     let vote: &CrdsData = gossip_crds.get(&vote)?;
@@ -834,7 +833,7 @@ impl ClusterInfo {
         if exists_newer_vote {
             return None;
         }
-        if num_crds_votes < MAX_LOCKOUT_HISTORY as u8 {
+        if num_crds_votes < MAX_VOTES {
             // Do not evict if there is space in crds
             Some(num_crds_votes)
         } else {
@@ -859,7 +858,7 @@ impl ClusterInfo {
                 tower
             );
         };
-        debug_assert!(vote_index < MAX_LOCKOUT_HISTORY as u8);
+        debug_assert!(vote_index < MAX_VOTES);
         self.push_vote_at_index(vote, vote_index);
     }
 
@@ -868,7 +867,7 @@ impl ClusterInfo {
             let self_pubkey = self.id();
             let gossip_crds =
                 self.time_gossip_read_lock("gossip_read_push_vote", &self.stats.push_vote_read);
-            (0..MAX_LOCKOUT_HISTORY as u8).find(|ix| {
+            (0..MAX_VOTES).find(|ix| {
                 let vote = CrdsValueLabel::Vote(*ix, self_pubkey);
                 let Some(vote) = gossip_crds.get::<&CrdsData>(&vote) else {
                     return false;
@@ -900,7 +899,7 @@ impl ClusterInfo {
                 );
                 return;
             };
-            debug_assert!(vote_index < MAX_LOCKOUT_HISTORY as u8);
+            debug_assert!(vote_index < MAX_VOTES);
             self.push_vote_at_index(refresh_vote, vote_index);
         }
     }
@@ -3072,7 +3071,10 @@ mod tests {
         solana_ledger::shred::Shredder,
         solana_net_utils::bind_to,
         solana_signer::Signer,
-        solana_vote_program::{vote_instruction, vote_state::Vote},
+        solana_vote_program::{
+            vote_instruction,
+            vote_state::{Vote, MAX_LOCKOUT_HISTORY},
+        },
         std::{
             iter::repeat_with,
             net::{IpAddr, Ipv4Addr},
@@ -3483,7 +3485,7 @@ mod tests {
         }
 
         let initial_votes = cluster_info.get_votes(&mut Cursor::default());
-        assert_eq!(initial_votes.len(), MAX_LOCKOUT_HISTORY);
+        assert_eq!(initial_votes.len(), MAX_VOTES as usize);
 
         // Trying to refresh a vote less than all votes in gossip should do nothing
         let refresh_slot = lowest_vote_slot - 1;
@@ -3518,7 +3520,7 @@ mod tests {
 
         // This should evict the latest vote since it's for a slot less than refresh_slot
         let votes = cluster_info.get_votes(&mut Cursor::default());
-        assert_eq!(votes.len(), MAX_LOCKOUT_HISTORY);
+        assert_eq!(votes.len(), MAX_VOTES as usize);
         assert!(votes.contains(&refresh_tx));
         assert!(!votes.contains(&first_vote.unwrap()));
     }
@@ -3688,7 +3690,7 @@ mod tests {
             cluster_info.push_vote(&tower, vote);
 
             let vote_slots = get_vote_slots(&cluster_info);
-            let min_vote = k.saturating_sub(MAX_LOCKOUT_HISTORY - 1) as u64;
+            let min_vote = k.saturating_sub(MAX_VOTES as usize - 1) as u64;
             assert!(vote_slots.into_iter().eq(min_vote..=(k as u64)));
             sleep(Duration::from_millis(1));
         }

gossip/src/crds_data.rs

@@ -27,9 +27,10 @@ pub(crate) const MAX_SLOT: u64 = 1_000_000_000_000_000;
 const MAX_ACCOUNTS_HASHES: usize = 16;
 
 pub(crate) type VoteIndex = u8;
-// TODO: Remove this in favor of vote_state::MAX_LOCKOUT_HISTORY once
-// the fleet is updated to the new ClusterInfo::push_vote code.
-const MAX_VOTES: VoteIndex = 32;
+// Until the cluster upgrades we allow votes from higher indices
+const OLD_MAX_VOTES: VoteIndex = 32;
+/// Number of votes per validator to store.
+pub const MAX_VOTES: VoteIndex = 12;
 
 pub(crate) type EpochSlotsIndex = u8;
 pub(crate) const MAX_EPOCH_SLOTS: EpochSlotsIndex = 255;
@@ -68,7 +69,7 @@ impl Sanitize for CrdsData {
         match self {
             CrdsData::LegacyContactInfo(val) => val.sanitize(),
             CrdsData::Vote(ix, val) => {
-                if *ix >= MAX_VOTES {
+                if *ix >= OLD_MAX_VOTES {
                     return Err(SanitizeError::ValueOutOfBounds);
                 }
                 val.sanitize()
@@ -539,7 +540,7 @@ mod test {
         let mut rng = rand::thread_rng();
         let keypair = Keypair::new();
         let vote = Vote::new(keypair.pubkey(), new_test_vote_tx(&mut rng), timestamp()).unwrap();
-        let vote = CrdsValue::new(CrdsData::Vote(MAX_VOTES, vote), &keypair);
+        let vote = CrdsValue::new(CrdsData::Vote(OLD_MAX_VOTES, vote), &keypair);
         assert!(vote.sanitize().is_err());
     }
 

local-cluster/tests/local_cluster.rs

@@ -20,7 +20,7 @@ use {
     },
     solana_download_utils::download_snapshot_archive,
     solana_entry::entry::create_ticks,
-    solana_gossip::gossip_service::discover_cluster,
+    solana_gossip::{crds_data::MAX_VOTES, gossip_service::discover_cluster},
     solana_ledger::{
         ancestor_iterator::AncestorIterator,
         bank_forks_utils,
@@ -4072,8 +4072,8 @@ fn run_duplicate_shreds_broadcast_leader(vote_on_duplicate: bool) {
                         None,
                     );
                     gossip_vote_index += 1;
-                    gossip_vote_index %= MAX_LOCKOUT_HISTORY;
-                    cluster_info.push_vote_at_index(vote_tx, gossip_vote_index as u8)
+                    gossip_vote_index %= MAX_VOTES;
+                    cluster_info.push_vote_at_index(vote_tx, gossip_vote_index);
                 }
             }
         },