feat(data_structures): order validators by stake when sampling superb…

…lock commitees

data_structures/src/staking/helpers.rs

@@ -287,22 +287,6 @@ pub struct CoinsAndAddresses<Coins, Address> {
     pub addresses: StakeKey<Address>,
 }
 
-/// Allows telling the `census` method in `Stakes` to source addresses from its internal `by_coins`
-/// following different strategies.
-#[repr(u8)]
-#[derive(Clone, Copy, Debug)]
-pub enum CensusStrategy {
-    /// Retrieve all addresses, ordered by decreasing power.
-    All = 0,
-    /// Retrieve every Nth address, ordered by decreasing power.
-    StepBy(usize) = 1,
-    /// Retrieve the most powerful N addresses, ordered by decreasing power.
-    Take(usize) = 2,
-    /// Retrieve a total of N addresses, evenly distributed from the index, ordered by decreasing
-    /// power.
-    Evenly(usize) = 3,
-}
-
 impl<const UNIT: u8, Address, Coins, Epoch, Nonce, Power> Serialize
     for Stakes<UNIT, Address, Coins, Epoch, Nonce, Power>
 where

data_structures/src/staking/stakes.rs

@@ -265,6 +265,20 @@ where
         self.by_validator.len()
     }
 
+    /// Retrieve all validators, ordered by the total amount of stake that they operate.
+    pub fn validators_by_stake(&self) -> impl Iterator<Item = (Address, Coins)> + Clone + '_ {
+        self.by_validator
+            .iter()
+            .map(|(address, entries)| {
+                let coins = entries.iter().fold(Coins::zero(), |acc, entry| {
+                    acc + entry.value.read().unwrap().coins
+                });
+
+                (address.clone(), coins)
+            })
+            .sorted_by_key(|(_, coins)| *coins)
+    }
+
     /// Tells what is the power of an identity in the network on a certain epoch.
     pub fn query_power<ISK>(
         &self,

data_structures/src/superblock.rs

@@ -68,7 +68,7 @@ pub enum SuperBlockConsensus {
 ///
 /// Different protocol versions populate this data differently:
 /// - In V1_X, this contained a complete list of all ARS identities.
-/// - In V2_X, it is expected to contain all validators instead.
+/// - In V2_X, it is expected to contain a list of validators instead.
 #[derive(Clone, Debug, Default, Eq, PartialEq, Serialize, Deserialize)]
 pub struct Census {
     // HashSet containing the identities

node/src/actors/chain_manager/mod.rs

@@ -2043,17 +2043,17 @@ impl ChainManager {
                 // - In V1_X protocols, the census was sourced from the ARS. Namely, it contains
                 //   all identities with non-zero reputation, ordered by decreasing reputation.
                 // - In V2_x protocols, the census is instead sourced from the stakes tracker.
-                //   Namely, it contains the two top quartiles of the most powerful validators,
-                //   ordered by power.
+                //   Namely, it contains the two top quartiles of the validators that operate the
+                //   most stake.
                 // Exceptionally, if a base census has been constructed above, all of this logic is
                 // skipped, and the base census is used.
                 let census = Census::new(base_census.unwrap_or(
                     if ProtocolVersion::from_epoch(block_epoch) < ProtocolVersion::V2_0 {
                         reputation_engine.get_rep_ordered_ars_list()
                     } else {
-                        let all_validators = act.chain_state.stakes.by_rank(Capability::Mining, block_epoch);
+                        let all_validators = act.chain_state.stakes.validators_by_stake();
                         let half_count = act.chain_state.stakes.validators_count() / 2;
-                        let top_validators = all_validators.map(|(StakeKey { validator, .. }, _)| validator).take(half_count).collect();
+                        let top_validators = all_validators.map(|(validator, _)| validator).take(half_count).collect();
 
                         top_validators
                     }));