Whitelist warmup key

Author: sigurpol

prdoc/pr_10947.prdoc

@@ -3,7 +3,7 @@ doc:
 - audience: Runtime Dev
   description: |-
     PR #10802 added `reset_read_write_count()` at the end of commit_db() to prevent warmup operations from appearing in benchmarking results. However, commit_db is called twice: one on `on_before_start()` closure before benchmark, and one after benchmark execution after benchmark.
-    This PR moves read_write_count() call before the post-benchmark commit_db() call.
+    This PR whitelists the warmup keys so that it doesn't appear in the read/write count.
 crates:
 - name: frame-benchmarking
   bump: patch

substrate/frame/benchmarking/src/utils.rs

@@ -293,13 +293,16 @@ pub trait Benchmarking {
 
 		// Warmup the memory allocator after bulk deallocation.
 		// After draining the overlay with many entries, the first new allocation can trigger memory
-		// defragmentation.
+		// defragmentation. The warmup key is whitelisted so these operations don't appear in
+		// benchmark results.
 		const WARMUP_KEY: &[u8] = b":benchmark_warmup:";
+		let mut whitelist = self.get_whitelist();
+		if !whitelist.iter().any(|k| k.key == WARMUP_KEY) {
+			whitelist.push(TrackedStorageKey::from(WARMUP_KEY.to_vec()));
+			self.set_whitelist(whitelist);
+		}
 		self.place_storage(WARMUP_KEY.to_vec(), Some(vec![0u8; 32]));
 		self.place_storage(WARMUP_KEY.to_vec(), None);
-
-		// Reset tracking so warmup operations don't appear in benchmark results.
-		self.reset_read_write_count();
 	}
 
 	/// Get the read/write count.

substrate/frame/benchmarking/src/v1.rs

@@ -1117,14 +1117,13 @@ macro_rules! impl_benchmark {
 					let elapsed_extrinsic = recording.elapsed_extrinsic().expect("elapsed time should be recorded");
 					let diff_pov = recording.diff_pov().unwrap_or_default();
 
-					// Capture read/write count BEFORE commit_db resets the counters
-					let read_write_count = $crate::benchmarking::read_write_count();
-					// Commit the changes to the database
+					// Commit the changes to get proper write count
 					$crate::benchmarking::commit_db();
 					$crate::__private::log::trace!(
 						target: "benchmark",
 						"End Benchmark: {} ns", elapsed_extrinsic
 					);
+					let read_write_count = $crate::benchmarking::read_write_count();
 					$crate::__private::log::trace!(
 						target: "benchmark",
 						"Read/Write Count {:?}", read_write_count