Performance improvements:

- reduce contention on mutation_lock by having 256 of them
- better lmdb defaults

src/block/manager.rs

@@ -93,7 +93,7 @@ pub struct BlockManager {
 	compression_level: Option<i32>,
 	background_tranquility: u32,
 
-	mutation_lock: Mutex<BlockManagerLocked>,
+	mutation_lock: [Mutex<BlockManagerLocked>; 256],
 
 	pub(crate) rc: BlockRc,
 
@@ -150,8 +150,6 @@ impl BlockManager {
 			.netapp
 			.endpoint("garage_block/manager.rs/Rpc".to_string());
 
-		let manager_locked = BlockManagerLocked();
-
 		let metrics = BlockManagerMetrics::new(resync_queue.clone(), resync_errors.clone());
 
 		let block_manager = Arc::new(Self {
@@ -159,7 +157,7 @@ impl BlockManager {
 			data_dir,
 			compression_level,
 			background_tranquility,
-			mutation_lock: Mutex::new(manager_locked),
+			mutation_lock: [(); 256].map(|_| Mutex::new(BlockManagerLocked())),
 			rc,
 			resync_queue,
 			resync_notify: Notify::new(),
@@ -313,14 +311,21 @@ impl BlockManager {
 
 	/// Write a block to disk
 	async fn write_block(&self, hash: &Hash, data: &DataBlock) -> Result<BlockRpc, Error> {
+		let tracer = opentelemetry::global::tracer("garage");
+
 		let write_size = data.inner_buffer().len() as u64;
 
-		let res = self
-			.mutation_lock
+		let res = self.mutation_lock[hash.as_slice()[0] as usize]
 			.lock()
+			.with_context(Context::current_with_span(
+				tracer.start("Acquire mutation_lock"),
+			))
 			.await
 			.write_block(hash, data, self)
 			.bound_record_duration(&self.metrics.block_write_duration)
+			.with_context(Context::current_with_span(
+				tracer.start("BlockManagerLocked::write_block"),
+			))
 			.await?;
 
 		self.metrics.bytes_written.add(write_size);
@@ -370,7 +375,7 @@ impl BlockManager {
 		if data.verify(*hash).is_err() {
 			self.metrics.corruption_counter.add(1);
 
-			self.mutation_lock
+			self.mutation_lock[hash.as_slice()[0] as usize]
 				.lock()
 				.await
 				.move_block_to_corrupted(hash, self)
@@ -384,8 +389,7 @@ impl BlockManager {
 
 	/// Check if this node should have a block, but don't actually have it
 	async fn need_block(&self, hash: &Hash) -> Result<bool, Error> {
-		let BlockStatus { exists, needed } = self
-			.mutation_lock
+		let BlockStatus { exists, needed } = self.mutation_lock[hash.as_slice()[0] as usize]
 			.lock()
 			.await
 			.check_block_status(hash, self)
@@ -608,8 +612,7 @@ impl BlockManager {
 	}
 
 	async fn resync_block(&self, hash: &Hash) -> Result<(), Error> {
-		let BlockStatus { exists, needed } = self
-			.mutation_lock
+		let BlockStatus { exists, needed } = self.mutation_lock[hash.as_slice()[0] as usize]
 			.lock()
 			.await
 			.check_block_status(hash, self)
@@ -694,7 +697,7 @@ impl BlockManager {
 				who.len()
 			);
 
-			self.mutation_lock
+			self.mutation_lock[hash.as_slice()[0] as usize]
 				.lock()
 				.await
 				.delete_if_unneeded(hash, self)