fix(pallet-qpow): correct weight calculation for on_finalize

pallets/qpow/src/benchmarking.rs

@@ -15,9 +15,10 @@ use sp_runtime::traits::Get;
 mod benchmarks {
 	use super::*;
 
+	/// Benchmark for the on_finalize hook which performs EMA-based difficulty adjustment.
 	#[benchmark]
-	fn on_finalize_max_history() {
-		// Setup state with maximum history size to test worst-case scenario
+	fn on_finalize() {
+		// Setup state with typical block for difficulty adjustment
 		let block_number = BlockNumberFor::<T>::from(1000u32);
 		frame_system::Pallet::<T>::set_block_number(block_number);
 
@@ -31,6 +32,9 @@ mod benchmarks {
 		pallet_timestamp::Pallet::<T>::set_timestamp(now);
 		<LastBlockTime<T>>::put(now.saturating_sub(T::TargetBlockTime::get()));
 
+		// Initialize EMA
+		<BlockTimeEma<T>>::put(T::TargetBlockTime::get());
+
 		#[block]
 		{
 			QPoW::<T>::on_finalize(block_number);

pallets/qpow/src/lib.rs

@@ -120,12 +120,12 @@ pub mod pallet {
 
 	#[pallet::hooks]
 	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {
-		// TODO: update this
 		fn on_initialize(_block_number: BlockNumberFor<T>) -> Weight {
-			<T as crate::Config>::WeightInfo::on_finalize_max_history()
+			<T as crate::Config>::WeightInfo::on_finalize()
 		}
 
-		/// Called at the end of each block.
+		/// Called at the end of each block to adjust mining difficulty based on
+		/// observed block times using Exponential Moving Average (EMA).
 		fn on_finalize(block_number: BlockNumberFor<T>) {
 			let current_difficulty = <CurrentDifficulty<T>>::get();
 			log::debug!(target: "qpow",

pallets/qpow/src/weights.rs

@@ -51,52 +51,52 @@ use core::marker::PhantomData;
 
 /// Weight functions needed for `pallet_qpow`.
 pub trait WeightInfo {
-	fn on_finalize_max_history() -> Weight;
+	fn on_finalize() -> Weight;
 }
 
 /// Weights for `pallet_qpow` using the Substrate node and recommended hardware.
 pub struct SubstrateWeight<T>(PhantomData<T>);
 impl<T: frame_system::Config> WeightInfo for SubstrateWeight<T> {
-	/// Storage: `QPoW::CurrentDifficulty` (r:1 w:1)
+	/// Storage: `QPoW::CurrentDifficulty` (r:2 w:1)
 	/// Proof: `QPoW::CurrentDifficulty` (`max_values`: Some(1), `max_size`: Some(64), added: 559, mode: `MaxEncodedLen`)
 	/// Storage: `Timestamp::Now` (r:1 w:0)
 	/// Proof: `Timestamp::Now` (`max_values`: Some(1), `max_size`: Some(8), added: 503, mode: `MaxEncodedLen`)
 	/// Storage: `QPoW::LastBlockTime` (r:1 w:1)
 	/// Proof: `QPoW::LastBlockTime` (`max_values`: Some(1), `max_size`: Some(8), added: 503, mode: `MaxEncodedLen`)
-	/// Storage: `QPoW::TotalWork` (r:1 w:1)
-	/// Proof: `QPoW::TotalWork` (`max_values`: Some(1), `max_size`: Some(64), added: 559, mode: `MaxEncodedLen`)
+	/// Storage: `QPoW::BlockTimeEma` (r:1 w:1)
+	/// Proof: `QPoW::BlockTimeEma` (`max_values`: Some(1), `max_size`: Some(8), added: 503, mode: `MaxEncodedLen`)
 	/// Storage: `QPoW::LastBlockDuration` (r:0 w:1)
 	/// Proof: `QPoW::LastBlockDuration` (`max_values`: Some(1), `max_size`: Some(8), added: 503, mode: `MaxEncodedLen`)
-	fn on_finalize_max_history() -> Weight {
+	fn on_finalize() -> Weight {
 		// Proof Size summary in bytes:
-		//  Measured:  `707`
-		//  Estimated: `23445`
-		// Minimum execution time: 213_000_000 picoseconds.
-		Weight::from_parts(217_000_000, 23445)
-			.saturating_add(T::DbWeight::get().reads(16_u64))
-			.saturating_add(T::DbWeight::get().writes(9_u64))
+		//  Measured:  `680`
+		//  Estimated: `1549`
+		// Minimum execution time: 106_000_000 picoseconds.
+		Weight::from_parts(109_000_000, 1549)
+			.saturating_add(T::DbWeight::get().reads(5_u64))
+			.saturating_add(T::DbWeight::get().writes(4_u64))
 	}
 }
 
 // For backwards compatibility and tests.
 impl WeightInfo for () {
-	/// Storage: `QPoW::CurrentDifficulty` (r:1 w:1)
+	/// Storage: `QPoW::CurrentDifficulty` (r:2 w:1)
 	/// Proof: `QPoW::CurrentDifficulty` (`max_values`: Some(1), `max_size`: Some(64), added: 559, mode: `MaxEncodedLen`)
 	/// Storage: `Timestamp::Now` (r:1 w:0)
 	/// Proof: `Timestamp::Now` (`max_values`: Some(1), `max_size`: Some(8), added: 503, mode: `MaxEncodedLen`)
 	/// Storage: `QPoW::LastBlockTime` (r:1 w:1)
 	/// Proof: `QPoW::LastBlockTime` (`max_values`: Some(1), `max_size`: Some(8), added: 503, mode: `MaxEncodedLen`)
-	/// Storage: `QPoW::TotalWork` (r:1 w:1)
-	/// Proof: `QPoW::TotalWork` (`max_values`: Some(1), `max_size`: Some(64), added: 559, mode: `MaxEncodedLen`)
+	/// Storage: `QPoW::BlockTimeEma` (r:1 w:1)
+	/// Proof: `QPoW::BlockTimeEma` (`max_values`: Some(1), `max_size`: Some(8), added: 503, mode: `MaxEncodedLen`)
 	/// Storage: `QPoW::LastBlockDuration` (r:0 w:1)
 	/// Proof: `QPoW::LastBlockDuration` (`max_values`: Some(1), `max_size`: Some(8), added: 503, mode: `MaxEncodedLen`)
-	fn on_finalize_max_history() -> Weight {
+	fn on_finalize() -> Weight {
 		// Proof Size summary in bytes:
-		//  Measured:  `707`
-		//  Estimated: `23445`
-		// Minimum execution time: 213_000_000 picoseconds.
-		Weight::from_parts(217_000_000, 23445)
-			.saturating_add(RocksDbWeight::get().reads(16_u64))
-			.saturating_add(RocksDbWeight::get().writes(9_u64))
+		//  Measured:  `680`
+		//  Estimated: `1549`
+		// Minimum execution time: 106_000_000 picoseconds.
+		Weight::from_parts(109_000_000, 1549)
+			.saturating_add(RocksDbWeight::get().reads(5_u64))
+			.saturating_add(RocksDbWeight::get().writes(4_u64))
 	}
 }