rusk: Split Block Generator reward into fixed reward and extra reward

rusk/src/lib/chain.rs

@@ -55,19 +55,31 @@ impl RuskNode {
 /// Calculates the value that the coinbase notes should contain.
 ///
 /// 10% of the reward value goes to the Dusk address (rounded down).
-/// 80% of the reward value goes to the Block generator (rounded up).
+/// 70% of the reward value is considered fixed reward for Block Generator.
+/// 10% of the reward value is considered extra reward for Block Generator.
 /// 10% of the reward value goes to the all validators/voters of previous block
 /// (rounded down).
 const fn coinbase_value(
     block_height: u64,
     dusk_spent: u64,
-) -> (Dusk, Dusk, Dusk) {
+) -> (Dusk, Dusk, Dusk, Dusk) {
     let value = emission_amount(block_height) + dusk_spent;
-    let dusk_value = value / 10;
-    let voters_value = dusk_value;
-    let generator_value = value - dusk_value - voters_value;
 
-    (dusk_value, generator_value, voters_value)
+    let one_tenth_reward = value / 10;
+
+    let dusk_value = one_tenth_reward;
+    let voters_value = one_tenth_reward;
+    let generator_extra_value = one_tenth_reward;
+
+    let generator_fixed_value =
+        value - dusk_value - voters_value - generator_extra_value;
+
+    (
+        dusk_value,
+        generator_fixed_value,
+        generator_extra_value,
+        voters_value,
+    )
 }
 
 /// This implements the emission schedule described in the economic paper.

rusk/src/lib/chain/rusk.rs

@@ -542,14 +542,21 @@ fn reward_slash_and_update_root(
     slashing: &[StakePublicKey],
     voters: Option<&[(StakePublicKey, usize)]>,
 ) -> Result<Vec<Event>> {
-    let (dusk_value, generator_reward, voters_reward) =
-        coinbase_value(block_height, dusk_spent);
-
-    if let Some(voters) = voters {
-        let credits: usize = voters.iter().map(|(_, credits)| credits).sum();
-        if credits == 0 && block_height > 1 {
-            return Err(InvalidCreditsCount(block_height, 0));
-        }
+    let (
+        dusk_value,
+        generator_fixed_reward,
+        generator_extra_reward,
+        voters_reward,
+    ) = coinbase_value(block_height, dusk_spent);
+
+    let credits = voters
+        .unwrap_or_default()
+        .iter()
+        .map(|(_, credits)| *credits as u64)
+        .sum::<u64>();
+
+    if voters.is_some() && credits == 0 && block_height > 1 {
+        return Err(InvalidCreditsCount(block_height, 0));
     }
 
     let credit_reward = voters_reward / 64 * 2;
@@ -569,6 +576,11 @@ fn reward_slash_and_update_root(
         reward = dusk_value
     );
 
+    let reward_per_quota = generator_extra_reward / (21 * 2);
+    let generator_curr_extra_reward =
+        credits.saturating_sub(43 * 2) * reward_per_quota;
+
+    let generator_reward = generator_fixed_reward + generator_curr_extra_reward;
     let r = session.call::<_, ()>(
         STAKE_CONTRACT,
         "reward",
@@ -580,7 +592,9 @@ fn reward_slash_and_update_root(
     debug!(
         event = "generator rewarded",
         voter = to_bs58(generator),
-        reward = generator_reward
+        total_reward = generator_reward,
+        extra_reward = generator_curr_extra_reward,
+        credits,
     );
 
     for (to_voter, credits) in voters.unwrap_or_default() {