Add feature to allow Aura collator to use full PoV size (#5393)

This PR introduces a feature that allows to optionally enable using the
full PoV size.

Technically, we're ready to enable it by default, but as corresponding
runtime changes have not been propagated to the system parachain
runtimes yet, doing so could put them at risk. On the other hand, there
are teams that could benefit from it right now, and it makes no sense
for them to wait for the fellowship release and everything.

---------

Co-authored-by: Andrei Sandu <54316454+sandreim@users.noreply.github.com>

cumulus/client/consensus/aura/Cargo.toml

@@ -54,3 +54,7 @@ polkadot-primitives = { workspace = true, default-features = true }
 polkadot-node-primitives = { workspace = true, default-features = true }
 polkadot-node-subsystem = { workspace = true, default-features = true }
 polkadot-overseer = { workspace = true, default-features = true }
+
+[features]
+# Allows collator to use full PoV size for block building
+full-pov-size = []

cumulus/client/consensus/aura/src/collators/basic.rs

@@ -237,6 +237,16 @@ where
 					.await
 			);
 
+			let allowed_pov_size = if cfg!(feature = "full-pov-size") {
+				validation_data.max_pov_size
+			} else {
+				// Set the block limit to 50% of the maximum PoV size.
+				//
+				// TODO: If we got benchmarking that includes the proof size,
+				// we should be able to use the maximum pov size.
+				validation_data.max_pov_size / 2
+			} as usize;
+
 			let maybe_collation = try_request!(
 				collator
 					.collate(
@@ -245,11 +255,7 @@ where
 						None,
 						(parachain_inherent_data, other_inherent_data),
 						params.authoring_duration,
-						// Set the block limit to 50% of the maximum PoV size.
-						//
-						// TODO: If we got benchmarking that includes the proof size,
-						// we should be able to use the maximum pov size.
-						(validation_data.max_pov_size / 2) as usize,
+						allowed_pov_size,
 					)
 					.await
 			);

cumulus/client/consensus/aura/src/collators/lookahead.rs

@@ -412,6 +412,16 @@ where
 				)
 				.await;
 
+				let allowed_pov_size = if cfg!(feature = "full-pov-size") {
+					validation_data.max_pov_size
+				} else {
+					// Set the block limit to 50% of the maximum PoV size.
+					//
+					// TODO: If we got benchmarking that includes the proof size,
+					// we should be able to use the maximum pov size.
+					validation_data.max_pov_size / 2
+				} as usize;
+
 				match collator
 					.collate(
 						&parent_header,
@@ -419,11 +429,7 @@ where
 						None,
 						(parachain_inherent_data, other_inherent_data),
 						params.authoring_duration,
-						// Set the block limit to 50% of the maximum PoV size.
-						//
-						// TODO: If we got benchmarking that includes the proof size,
-						// we should be able to use the maximum pov size.
-						(validation_data.max_pov_size / 2) as usize,
+						allowed_pov_size,
 					)
 					.await
 				{

cumulus/client/consensus/aura/src/collators/slot_based/block_builder_task.rs

@@ -350,6 +350,16 @@ where
 			)
 			.await;
 
+			let allowed_pov_size = if cfg!(feature = "full-pov-size") {
+				validation_data.max_pov_size
+			} else {
+				// Set the block limit to 50% of the maximum PoV size.
+				//
+				// TODO: If we got benchmarking that includes the proof size,
+				// we should be able to use the maximum pov size.
+				validation_data.max_pov_size / 2
+			} as usize;
+
 			let Ok(Some(candidate)) = collator
 				.build_block_and_import(
 					&parent_header,
@@ -357,11 +367,7 @@ where
 					None,
 					(parachain_inherent_data, other_inherent_data),
 					authoring_duration,
-					// Set the block limit to 50% of the maximum PoV size.
-					//
-					// TODO: If we got benchmarking that includes the proof size,
-					// we should be able to use the maximum pov size.
-					(validation_data.max_pov_size / 2) as usize,
+					allowed_pov_size,
 				)
 				.await
 			else {

prdoc/pr_5393.prdoc

+# Schema: Polkadot SDK PRDoc Schema (prdoc) v1.0.0
+# See doc at https://raw.githubusercontent.com/paritytech/polkadot-sdk/master/prdoc/schema_user.json
+
+title: Allow to enable full PoV size
+
+doc:
+  - audience: Node Dev
+    description: |
+      A feature is introduced allowing a collator to enable full PoV size at compile time.
+      WARNING: To use this feature, security considerations must be understood and the latest
+      SDK version must be used.
+
+crates:
+  - name: cumulus-client-consensus-aura
+    bump: minor