Support mdraid hierarchies for storage topology detection.

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/utils/sys.rs

@@ -5,7 +5,7 @@ use std::path::PathBuf;
 
 pub use compute::available_parallelism;
 
-use crate::{Result, debug};
+use crate::{Result, at, debug};
 
 /// This is needed for opening lots of file descriptors, which tends to
 /// happen more often when using RocksDB and making lots of federation
@@ -51,3 +51,13 @@ pub fn current_exe_deleted() -> bool {
 			.is_some_and(|exe| exe.ends_with(" (deleted)"))
 	})
 }
+
+/// Parse the `KEY=VALUE` contents of a `uevent` file searching for `key` and
+/// returning the `value`.
+fn _uevent_get<'a>(uevent: &'a str, key: &'a str) -> Option<&'a str> {
+	uevent
+		.lines()
+		.filter_map(|line| line.split_once('='))
+		.find(|&(key_, _)| key.eq(key_))
+		.map(at!(1))
+}

src/core/utils/sys/compute.rs

@@ -9,7 +9,11 @@ type Id = usize;
 type Mask = u128;
 type Masks = [Mask; MASK_BITS];
 
-const MASK_BITS: usize = 128;
+const MASK_BITS: usize = CORES_MAX;
+
+/// Maximum number of cores we support; for now limited to bits of our mask
+/// integral.
+pub const CORES_MAX: usize = 128;
 
 /// The mask of logical cores available to the process (at startup).
 static CORES_AVAILABLE: LazyLock<Mask> = LazyLock::new(|| into_mask(query_cores_available()));

src/core/utils/sys/storage.rs

@@ -16,9 +16,22 @@ use crate::{
 	utils::{result::LogDebugErr, string::SplitInfallible},
 };
 
-/// Device characteristics useful for random access throughput
+/// Multi-Device (md) i.e. software raid properties.
 #[derive(Clone, Debug, Default)]
-pub struct Parallelism {
+pub struct MultiDevice {
+	/// Type of raid (i.e. `raid1`); None if no raid present or detected.
+	pub level: Option<String>,
+
+	/// Number of participating devices.
+	pub raid_disks: usize,
+
+	/// The MQ's discovered on the devices; or empty.
+	pub md: Vec<MultiQueue>,
+}
+
+/// Multi-Queue (mq) characteristics.
+#[derive(Clone, Debug, Default)]
+pub struct MultiQueue {
 	/// Number of requests for the device.
 	pub nr_requests: Option<usize>,
 
@@ -26,7 +39,7 @@ pub struct Parallelism {
 	pub mq: Vec<Queue>,
 }
 
-/// Device queue characteristics
+/// Single-queue characteristics
 #[derive(Clone, Debug, Default)]
 pub struct Queue {
 	/// Queue's indice.
@@ -39,18 +52,59 @@ pub struct Queue {
 	pub cpu_list: Vec<usize>,
 }
 
-/// Get device characteristics useful for random access throughput by name.
+/// Get properties of a MultiDevice (md) storage system
 #[must_use]
-pub fn parallelism(path: &Path) -> Parallelism {
+pub fn md_discover(path: &Path) -> MultiDevice {
 	let dev_id = dev_from_path(path)
 		.log_debug_err()
 		.unwrap_or_default();
 
-	let mq_path = block_path(dev_id).join("mq/");
+	let md_path = block_path(dev_id).join("md/");
 
-	let nr_requests_path = block_path(dev_id).join("queue/nr_requests");
+	let raid_disks_path = md_path.join("raid_disks");
 
-	Parallelism {
+	let raid_disks: usize = read_to_string(&raid_disks_path)
+		.ok()
+		.as_deref()
+		.map(str::trim)
+		.map(str::parse)
+		.flat_ok()
+		.unwrap_or(0);
+
+	let single_fallback = raid_disks.eq(&0).then(|| block_path(dev_id));
+
+	MultiDevice {
+		raid_disks,
+
+		level: read_to_string(md_path.join("level"))
+			.ok()
+			.as_deref()
+			.map(str::trim)
+			.map(ToOwned::to_owned),
+
+		md: (0..raid_disks)
+			.map(|i| format!("rd{i}/block"))
+			.map(|path| md_path.join(&path))
+			.filter_map(|ref path| path.canonicalize().ok())
+			.map(|mut path| {
+				path.pop();
+				path
+			})
+			.chain(single_fallback)
+			.map(|path| mq_discover(&path))
+			.filter(|mq| !mq.mq.is_empty())
+			.collect(),
+	}
+}
+
+/// Get properties of a MultiQueue within a MultiDevice.
+#[must_use]
+fn mq_discover(path: &Path) -> MultiQueue {
+	let mq_path = path.join("mq/");
+
+	let nr_requests_path = path.join("queue/nr_requests");
+
+	MultiQueue {
 		nr_requests: read_to_string(&nr_requests_path)
 			.ok()
 			.as_deref()
@@ -68,13 +122,13 @@ pub fn parallelism(path: &Path) -> Parallelism {
 					.as_ref()
 					.is_ok_and(FileType::is_dir)
 			})
-			.map(|dir| queue_parallelism(&dir.path()))
+			.map(|dir| queue_discover(&dir.path()))
 			.collect(),
 	}
 }
 
-/// Get device queue characteristics by mq path on sysfs(5)
+/// Get properties of a Queue within a MultiQueue.
-fn queue_parallelism(dir: &Path) -> Queue {
+fn queue_discover(dir: &Path) -> Queue {
 	let queue_id = dir.file_name();
 
 	let nr_tags_path = dir.join("nr_tags");

src/database/pool/configure.rs

@@ -1,39 +1,69 @@
 use std::{path::PathBuf, sync::Arc};
 
 use tuwunel_core::{
-	Server, debug, debug_info, expected, is_equal_to,
+	Server, debug,
+	debug::INFO_SPAN_LEVEL,
+	debug_info, debug_warn, expected, info, is_equal_to,
 	utils::{
+		BoolExt,
 		math::usize_from_f64,
 		result::LogDebugErr,
 		stream,
 		stream::{AMPLIFICATION_LIMIT, WIDTH_LIMIT},
-		sys::{compute::is_core_available, storage},
+		sys::{
+			compute::{CORES_MAX, available_parallelism, is_core_available},
+			storage,
+		},
 	},
 };
 
 use super::{QUEUE_LIMIT, WORKER_LIMIT};
 
+#[tracing::instrument(
+	level = INFO_SPAN_LEVEL,
+	skip_all,
+	ret(level = "trace"),
+)]
 pub(super) fn configure(server: &Arc<Server>) -> (usize, Vec<usize>, Vec<usize>) {
 	let config = &server.config;
+	let num_cores = available_parallelism();
 
 	// This finds the block device and gathers all the properties we need.
 	let path: PathBuf = config.database_path.clone();
 	let device_name = storage::name_from_path(&path)
 		.log_debug_err()
 		.ok();
-	let device_prop = storage::parallelism(&path);
+
+	let devices = storage::md_discover(&path);
+	let topology_detected = devices.md.is_empty().is_false();
+	debug!(?topology_detected, ?device_name, ?devices);
 
 	// The default worker count is masked-on if we didn't find better information.
-	let default_worker_count = device_prop
+	let default_worker_count = topology_detected
-		.mq
+		.is_false()
-		.is_empty()
 		.then_some(config.db_pool_workers);
 
-	// Determine the worker groupings. Each indice represents a hardware queue and
+	// Sum the total number of possible tags. When no hardware detected this will
-	// contains the number of workers which will service it.
+	// default to the default_worker_count
-	let worker_counts: Vec<_> = device_prop
+	let total_tags = devices
-		.mq
+		.md
 		.iter()
+		.flat_map(|md| md.mq.iter())
+		.filter(|mq| mq.cpu_list.iter().copied().any(is_core_available))
+		.filter_map(|mq| mq.nr_tags)
+		.chain(default_worker_count)
+		.fold(0_usize, usize::saturating_add);
+
+	// Determine the worker groupings. Each indice represents a hardware queue and
+	// contains the number of workers which will service it. This vector is
+	// truncated to the number of cores on systems which have multiple hardware
+	// queues per core. When no hardware is detected this defaults to one queue with
+	// a default count of workers.
+	let worker_counts: Vec<_> = devices
+		.md
+		.iter()
+		.inspect(|md| debug!(?md))
+		.flat_map(|md| md.mq.iter())
 		.filter(|mq| mq.cpu_list.iter().copied().any(is_core_available))
 		.map(|mq| {
 			let shares = mq
@@ -47,13 +77,20 @@ pub(super) fn configure(server: &Arc<Server>) -> (usize, Vec<usize>, Vec<usize>)
 				.db_pool_workers_limit
 				.saturating_mul(shares);
 
-			let limit = device_prop
+			let limit = devices.md.iter().fold(0_usize, |acc, mq| {
-				.nr_requests
+				mq.nr_requests
-				.map_or(limit, |nr| nr.min(limit));
+					.map(|nr| nr.min(limit))
+					.or(Some(limit))
+					.map(|nr| acc.saturating_add(nr))
+					.unwrap_or(acc)
+			});
+
+			debug!(?mq, ?shares, ?limit);
 
 			mq.nr_tags.unwrap_or(WORKER_LIMIT.0).min(limit)
 		})
 		.chain(default_worker_count)
+		.take(num_cores)
 		.collect();
 
 	// Determine our software queue size for each hardware queue. This is the mpmc
@@ -67,14 +104,18 @@ pub(super) fn configure(server: &Arc<Server>) -> (usize, Vec<usize>, Vec<usize>)
 		})
 		.collect();
 
-	// Determine the CPU affinities of each hardware queue. Each indice is a cpu and
+	// Determine the CPU affinities of each hardware queue. Each indice is a core
-	// each value is the associated hardware queue. There is a little shiftiness
+	// and each value is the associated hardware queue. On systems which share
-	// going on because cpu's which are not available to the process are filtered
+	// queues between cores some values will be repeated; on systems with multiple
-	// out, similar to the worker_counts.
+	// queues per core the affinities are assumed to match and we don't require a
-	let topology = device_prop
+	// vector of vectors. There is a little hiftiness going on because cpu's which
-		.mq
+	// are not available to the process are filtered out, similar to the
+	// worker_counts.
+	let topology = devices
+		.md
 		.iter()
-		.fold(vec![0; 128], |mut topology, mq| {
+		.flat_map(|md| md.mq.iter())
+		.fold(vec![0; CORES_MAX], |mut topology, mq| {
 			mq.cpu_list
 				.iter()
 				.filter(|&&id| is_core_available(id))
@@ -83,13 +124,17 @@ pub(super) fn configure(server: &Arc<Server>) -> (usize, Vec<usize>, Vec<usize>)
 				});
 
 			topology
-		});
+		})
+		.into_iter()
+		.take(num_cores)
+		.collect();
 
 	// Regardless of the capacity of all queues we establish some limit on the total
 	// number of workers; this is hopefully hinted by nr_requests.
-	let max_workers = device_prop
+	let max_workers = devices
-		.mq
+		.md
 		.iter()
+		.flat_map(|md| md.mq.iter())
 		.filter_map(|mq| mq.nr_tags)
 		.chain(default_worker_count)
 		.fold(0_usize, usize::saturating_add)
@@ -103,21 +148,32 @@ pub(super) fn configure(server: &Arc<Server>) -> (usize, Vec<usize>, Vec<usize>)
 
 	// After computing all of the above we can update the global automatic stream
 	// width, hopefully with a better value tailored to this system.
+	let num_queues = queue_sizes.len();
 	if config.stream_width_scale > 0.0 {
-		let num_queues = queue_sizes.len().max(1);
+		update_stream_width(server, num_queues, total_workers, total_tags);
-		update_stream_width(server, num_queues, total_workers);
 	}
 
-	debug_info!(
+	if topology_detected {
-		device_name = ?device_name
+		debug_info!(?topology, ?worker_counts, ?queue_sizes, "Frontend topology",);
-			.as_deref()
+		info!(
-			.unwrap_or("None"),
+			device_name = ?device_name.as_deref().unwrap_or("None"),
-		?worker_counts,
+			?num_cores,
-		?queue_sizes,
+			?num_queues,
-		?total_workers,
+			?total_workers,
-		stream_width = ?stream::automatic_width(),
+			?total_tags,
-		"Frontend topology",
+			stream_width = ?stream::automatic_width(),
-	);
+			amplification = ?stream::automatic_amplification(),
+			"Frontend topology",
+		);
+	} else {
+		debug_warn!(
+			device_name = ?device_name.as_deref().unwrap_or("None"),
+			?total_workers,
+			stream_width = ?stream::automatic_width(),
+			amplification = ?stream::automatic_amplification(),
+			"Storage hardware not detected for database directory; assuming defaults.",
+		);
+	}
 
 	assert!(total_workers > 0, "some workers expected");
 	assert!(!queue_sizes.is_empty(), "some queues expected");
@@ -130,26 +186,36 @@ pub(super) fn configure(server: &Arc<Server>) -> (usize, Vec<usize>, Vec<usize>)
 }
 
 #[allow(clippy::as_conversions, clippy::cast_precision_loss)]
-fn update_stream_width(server: &Arc<Server>, num_queues: usize, total_workers: usize) {
+fn update_stream_width(
+	server: &Arc<Server>,
+	num_queues: usize,
+	total_workers: usize,
+	total_tags: usize,
+) {
 	let config = &server.config;
 	let scale: f64 = config.stream_width_scale.min(100.0).into();
+	let auto_scale = total_tags as f64 / total_workers as f64;
+	let auto_scale_width = auto_scale / num_queues as f64;
 
-	let req_width = expected!(total_workers / num_queues).next_multiple_of(2);
+	let req_width = expected!(total_workers / num_queues).next_multiple_of(8);
-	let req_width = req_width as f64;
+	let req_width = req_width as f64 * auto_scale_width.clamp(1.0, 4.0);
 	let req_width = usize_from_f64(req_width * scale)
 		.expect("failed to convert f64 to usize")
+		.next_multiple_of(4)
 		.clamp(WIDTH_LIMIT.0, WIDTH_LIMIT.1);
 
-	let req_amp = config.stream_amplification as f64;
+	let req_amp = config.stream_amplification as f64 * auto_scale.clamp(1.0, 4.0);
 	let req_amp = usize_from_f64(req_amp * scale)
 		.expect("failed to convert f64 to usize")
+		.next_multiple_of(64)
 		.clamp(AMPLIFICATION_LIMIT.0, AMPLIFICATION_LIMIT.1);
 
 	let (old_width, new_width) = stream::set_width(req_width);
 	let (old_amp, new_amp) = stream::set_amplification(req_amp);
 	debug!(
-		scale = ?config.stream_width_scale,
+		config_scale = ?config.stream_width_scale,
-		?num_queues,
+		?auto_scale,
+		?auto_scale_width,
 		?req_width,
 		?old_width,
 		?new_width,