Fix algorithmic complexity of on-demand scheduler with regards to number of cores.

Cargo.toml

@@ -604,3 +604,6 @@ wasmi = { opt-level = 3 }
 x25519-dalek = { opt-level = 3 }
 yamux = { opt-level = 3 }
 zeroize = { opt-level = 3 }
+
+[patch.crates-io]
+scale-info = { git = 'https://github.com/paritytech/scale-info.git', branch="master" }

polkadot/primitives/src/lib.rs

@@ -58,7 +58,7 @@ pub use v6::{
 	ValidationCodeHash, ValidatorId, ValidatorIndex, ValidatorSignature, ValidityAttestation,
 	ValidityError, ASSIGNMENT_KEY_TYPE_ID, LEGACY_MIN_BACKING_VOTES, LOWEST_PUBLIC_ID,
 	MAX_CODE_SIZE, MAX_HEAD_DATA_SIZE, MAX_POV_SIZE, ON_DEMAND_DEFAULT_QUEUE_MAX_SIZE,
-	PARACHAINS_INHERENT_IDENTIFIER, PARACHAIN_KEY_TYPE_ID,
+	ON_DEMAND_MAX_QUEUE_MAX_SIZE, PARACHAINS_INHERENT_IDENTIFIER, PARACHAIN_KEY_TYPE_ID,
 };
 
 #[cfg(feature = "std")]

polkadot/primitives/src/v6/mod.rs

@@ -395,6 +395,13 @@ pub const MAX_POV_SIZE: u32 = 5 * 1024 * 1024;
 /// Can be adjusted in configuration.
 pub const ON_DEMAND_DEFAULT_QUEUE_MAX_SIZE: u32 = 10_000;
 
+/// Maximum for maximum queue size.
+///
+/// Setting `on_demand_queue_max_size` to a value higher than this is unsound. This is more a
+/// theoretical limit, just below enough what the target type supports, so comparisons are possible
+/// even with indices that are overflowing the underyling type.
+pub const ON_DEMAND_MAX_QUEUE_MAX_SIZE: u32 = 1_000_000_000;
+
 /// Backing votes threshold used from the host prior to runtime API version 6 and from the runtime
 /// prior to v9 configuration migration.
 pub const LEGACY_MIN_BACKING_VOTES: u32 = 2;

polkadot/runtime/parachains/src/assigner_on_demand/benchmarking.rs

@@ -70,11 +70,7 @@ mod benchmarks {
 		let para_id = ParaId::from(111u32);
 		init_parathread::<T>(para_id);
 		T::Currency::make_free_balance_be(&caller, BalanceOf::<T>::max_value());
-		let order = EnqueuedOrder::new(para_id);
-
-		for _ in 0..s {
-			Pallet::<T>::add_on_demand_order(order.clone(), QueuePushDirection::Back).unwrap();
-		}
+		Pallet::<T>::populate_queue(para_id, s);
 
 		#[extrinsic_call]
 		_(RawOrigin::Signed(caller.into()), BalanceOf::<T>::max_value(), para_id)
@@ -87,11 +83,8 @@ mod benchmarks {
 		let para_id = ParaId::from(111u32);
 		init_parathread::<T>(para_id);
 		T::Currency::make_free_balance_be(&caller, BalanceOf::<T>::max_value());
-		let order = EnqueuedOrder::new(para_id);
 
-		for _ in 0..s {
-			Pallet::<T>::add_on_demand_order(order.clone(), QueuePushDirection::Back).unwrap();
-		}
+		Pallet::<T>::populate_queue(para_id, s);
 
 		#[extrinsic_call]
 		_(RawOrigin::Signed(caller.into()), BalanceOf::<T>::max_value(), para_id)