feat: new leader schedule by vote delegation

ledger/src/leader_schedule.rs

@@ -4,6 +4,7 @@ use {
     rand_chacha::{rand_core::SeedableRng, ChaChaRng},
     solana_pubkey::Pubkey,
     solana_sdk::clock::Epoch,
+    solana_vote::vote_account::VoteAccountsHashMap,
     std::{collections::HashMap, convert::identity, ops::Index, sync::Arc},
 };
 
@@ -22,6 +23,27 @@ pub struct LeaderSchedule {
 }
 
 impl LeaderSchedule {
+    // Note: passing in zero vote accounts will cause a panic.
+    pub fn new_by_vote_delegation(
+        vote_accounts_map: &VoteAccountsHashMap,
+        epoch: Epoch,
+        len: u64,
+        repeat: u64,
+    ) -> Self {
+        let stakes: Vec<_> = vote_accounts_map
+            .iter()
+            .map(|(vote_pubkey, (stake, _account))| (*vote_pubkey, *stake))
+            .collect();
+        let slot_leaders = Self::stake_weighted_slot_leaders(
+            stakes,
+            |vote_key| *vote_accounts_map.get(vote_key).unwrap().1.node_pubkey(),
+            epoch,
+            len,
+            repeat,
+        );
+        Self::new_from_schedule(slot_leaders)
+    }
+
     // Note: passing in zero stakers will cause a panic.
     pub fn new_by_node_total_stake(
         stakes: &HashMap<Pubkey, u64>,
@@ -33,13 +55,15 @@ impl LeaderSchedule {
             .iter()
             .map(|(pubkey, stake)| (*pubkey, *stake))
             .collect();
-        let slot_leaders = Self::stake_weighted_slot_leaders(stakes, epoch, len, repeat);
+        let slot_leaders =
+            Self::stake_weighted_slot_leaders(stakes, |leader| *leader, epoch, len, repeat);
         Self::new_from_schedule(slot_leaders)
     }
 
     // Note: passing in zero stakers will cause a panic.
     fn stake_weighted_slot_leaders(
         mut stakes: Vec<(Pubkey, u64)>,
+        get_leader_node: impl Fn(&Pubkey) -> Pubkey,
         epoch: Epoch,
         len: u64,
         repeat: u64,
@@ -54,7 +78,7 @@ impl LeaderSchedule {
         (0..len)
             .map(|i| {
                 if i % repeat == 0 {
-                    current_node = ids[weighted_index.sample(rng)];
+                    current_node = get_leader_node(&ids[weighted_index.sample(rng)]);
                 }
                 current_node
             })

ledger/src/leader_schedule_utils.rs

@@ -10,14 +10,33 @@ use {
 
 /// Return the leader schedule for the given epoch.
 pub fn leader_schedule(epoch: Epoch, bank: &Bank) -> Option<LeaderSchedule> {
-    bank.epoch_staked_nodes(epoch).map(|stakes| {
-        LeaderSchedule::new_by_node_total_stake(
-            &stakes,
-            epoch,
-            bank.get_slots_in_epoch(epoch),
-            NUM_CONSECUTIVE_LEADER_SLOTS,
-        )
-    })
+    let use_new_leader_schedule = match bank
+        .feature_set
+        .new_leader_schedule_epoch(bank.epoch_schedule())
+    {
+        Some(new_leader_schedule_epoch) => epoch >= new_leader_schedule_epoch,
+        None => false,
+    };
+
+    if use_new_leader_schedule {
+        bank.epoch_vote_accounts(epoch).map(|vote_accounts_map| {
+            LeaderSchedule::new_by_vote_delegation(
+                vote_accounts_map,
+                epoch,
+                bank.get_slots_in_epoch(epoch),
+                NUM_CONSECUTIVE_LEADER_SLOTS,
+            )
+        })
+    } else {
+        bank.epoch_staked_nodes(epoch).map(|stakes| {
+            LeaderSchedule::new_by_node_total_stake(
+                &stakes,
+                epoch,
+                bank.get_slots_in_epoch(epoch),
+                NUM_CONSECUTIVE_LEADER_SLOTS,
+            )
+        })
+    }
 }
 
 /// Map of leader base58 identity pubkeys to the slot indices relative to the first epoch slot

sdk/feature-set/src/lib.rs

@@ -920,6 +920,10 @@ pub mod reserve_minimal_cus_for_builtin_instructions {
     solana_pubkey::declare_id!("C9oAhLxDBm3ssWtJx1yBGzPY55r2rArHmN1pbQn6HogH");
 }
 
+pub mod enable_vote_address_leader_schedule {
+    solana_pubkey::declare_id!("5JsG4NWH8Jbrqdd8uL6BNwnyZK3dQSoieRXG5vmofj9y");
+}
+
 pub mod raise_block_limits_to_50m {
     solana_pubkey::declare_id!("5oMCU3JPaFLr8Zr4ct7yFA7jdk6Mw1RmB8K4u9ZbS42z");
 }
@@ -1149,6 +1153,7 @@ lazy_static! {
         (deplete_cu_meter_on_vm_failure::id(), "Deplete compute meter for vm errors SIMD-0182 #3993"),
         (reserve_minimal_cus_for_builtin_instructions::id(), "Reserve minimal CUs for builtin instructions SIMD-170 #2562"),
         (raise_block_limits_to_50m::id(), "Raise block limit to 50M SIMD-0207"),
+        (enable_vote_address_leader_schedule::id(), "Enable vote address leader schedule SIMD-0180 #4573"),
         (fix_alt_bn128_multiplication_input_length::id(), "fix alt_bn128 multiplication input length SIMD-0222 #3686"),
         /*************** ADD NEW FEATURES HERE ***************/
     ]
@@ -1212,6 +1217,19 @@ impl FeatureSet {
         self.active.get(feature_id).copied()
     }
 
+    pub fn new_leader_schedule_epoch(&self, epoch_schedule: &EpochSchedule) -> Option<u64> {
+        // check the epoch of the slot when the new leader schedule feature was
+        // activated and then use the following epoch to start using the new
+        // leader schedule.
+        const NEW_LEADER_SCHEDULE_EPOCH_DELAY: u64 = 1;
+        self.activated_slot(&enable_vote_address_leader_schedule::id())
+            .map(|slot| {
+                epoch_schedule
+                    .get_epoch(slot)
+                    .wrapping_add(NEW_LEADER_SCHEDULE_EPOCH_DELAY)
+            })
+    }
+
     /// List of enabled features that trigger full inflation
     pub fn full_inflation_features_enabled(&self) -> AHashSet<Pubkey> {
         let mut hash_set = FULL_INFLATION_FEATURE_PAIRS