childkey tax rate

pallets/admin-utils/src/lib.rs

@@ -1682,6 +1682,18 @@ pub mod pallet {
             pallet_subtensor::Pallet::<T>::set_owner_immune_neuron_limit(netuid, immune_neurons)?;
             Ok(())
         }
+
+        /// Sets the childkey tax rate
+        #[pallet::call_index(73)]
+        #[pallet::weight(Weight::from_parts(15_000_000, 0))]
+        pub fn sudo_set_childkey_tax_rate(
+            origin: OriginFor<T>,
+            childkey_tax_rate: u16,
+        ) -> DispatchResult {
+            ensure_root(origin)?;
+            pallet_subtensor::Pallet::<T>::set_childkey_tax_rate(childkey_tax_rate)?;
+            Ok(())
+        }
     }
 }
 

pallets/subtensor/src/coinbase/run_coinbase.rs

@@ -743,6 +743,7 @@ impl<T: Config> Pallet<T> {
         // Calculate the hotkey's share of the validator emission based on its childkey take
         let validating_emission: U96F32 = U96F32::saturating_from_num(dividends);
         let mut remaining_emission: U96F32 = validating_emission;
+
         let childkey_take_proportion: U96F32 =
             U96F32::saturating_from_num(Self::get_childkey_take(hotkey, netuid))
                 .safe_div(U96F32::saturating_from_num(u16::MAX));
@@ -817,6 +818,14 @@ impl<T: Config> Pallet<T> {
             // Remove this emission from the remaining emission.
             remaining_emission = remaining_emission.saturating_sub(parent_emission);
 
+            let parent_emission_tax = parent_emission
+                .saturating_mul(U96F32::saturating_from_num(Self::get_childkey_tax_rate()))
+                .safe_div(U96F32::saturating_from_num(u16::MAX));
+            log::debug!("Parent emission tax: {parent_emission_tax:?} for hotkey {hotkey:?}");
+
+            parent_emission = parent_emission.saturating_sub(parent_emission_tax);
+            log::debug!("Parent emission after tax: {parent_emission:?} for hotkey {hotkey:?}");
+
             // Get the childkey take for this parent.
             let child_emission_take: U96F32 = if parent_owner == childkey_owner {
                 // The parent is from the same coldkey, so we don't remove any childkey take.

pallets/subtensor/src/lib.rs

@@ -1482,6 +1482,14 @@ pub mod pallet {
     pub type ImmuneOwnerUidsLimit<T> =
         StorageMap<_, Identity, NetUid, u16, ValueQuery, DefaultImmuneOwnerUidsLimit<T>>;
 
+    #[pallet::type_value]
+    /// Default value for childkey tax rate, 18%
+    pub fn DefaultChildkeyTaxRate<T: Config>() -> u16 {
+        11_796
+    }
+    #[pallet::storage]
+    pub type ChildkeyTaxRate<T> = StorageValue<_, u16, ValueQuery, DefaultChildkeyTaxRate<T>>;
+
     /// =======================================
     /// ==== Subnetwork Consensus Storage  ====
     /// =======================================

pallets/subtensor/src/macros/dispatches.rs

@@ -120,9 +120,9 @@ mod dispatches {
         /// 	- On failure for each failed item in the batch.
         ///
         #[pallet::call_index(80)]
-        #[pallet::weight((Weight::from_parts(19_330_000, 0)
-        .saturating_add(T::DbWeight::get().reads(1_u64))
-        .saturating_add(T::DbWeight::get().writes(0_u64)), DispatchClass::Normal, Pays::No))]
+        #[pallet::weight((Weight::from_parts(94_830_000, 0)
+        .saturating_add(T::DbWeight::get().reads(14_u64))
+        .saturating_add(T::DbWeight::get().writes(2_u64)), DispatchClass::Normal, Pays::No))]
         pub fn batch_set_weights(
             origin: OriginFor<T>,
             netuids: Vec<Compact<NetUid>>,

pallets/subtensor/src/utils/misc.rs

@@ -829,4 +829,26 @@ impl<T: Config> Pallet<T> {
         ImmuneOwnerUidsLimit::<T>::insert(netuid, limit);
         Ok(())
     }
+
+    /// Get the childkey tax rate
+    ///
+    /// # Returns
+    /// - `u16` - The childkey tax rate.
+    pub fn get_childkey_tax_rate() -> u16 {
+        ChildkeyTaxRate::<T>::get()
+    }
+
+    /// Set the childkey tax rate
+    ///
+    /// # Arguments
+    ///
+    /// * `childkey_tax_rate` - The new childkey tax rate.
+    ///
+    /// # Returns
+    /// - `Ok(())` on success.
+    /// - `Err(Error::<T>::InvalidValue)` if `childkey_tax_rate` is outside `[0, 100]`.
+    pub fn set_childkey_tax_rate(childkey_tax_rate: u16) -> DispatchResult {
+        ChildkeyTaxRate::<T>::set(childkey_tax_rate);
+        Ok(())
+    }
 }

runtime/src/lib.rs

@@ -220,7 +220,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
     //   `spec_version`, and `authoring_version` are the same between Wasm and native.
     // This value is set to 100 to notify Polkadot-JS App (https://polkadot.js.org/apps) to use
     //   the compatible custom types.
-    spec_version: 307,
+    spec_version: 308,
     impl_version: 1,
     apis: RUNTIME_API_VERSIONS,
     transaction_version: 1,