add rocksdb compaction thread priority/iopriority w/ conf

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

conduwuit-example.toml

@@ -387,6 +387,14 @@ allow_profile_lookup_federation_requests = true
 # Defaults to your CPU physical core count (not logical threads).
 #rocksdb_parallelism_threads = 0
 
+# Enables idle IO priority for compaction thread. This prevents any unexpected lag in the server's operation and
+# is usually a good idea. Enabled by default.
+#rocksdb_compaction_ioprio_idle = true
+
+# Enables idle CPU priority for compaction thread. This is not enabled by default to prevent compaction from
+# falling too far behind on busy systems.
+#rocksdb_compaction_prio_idle = false
+
 # Maximum number of LOG files RocksDB will keep. This must *not* be set to 0. It must be at least 1.
 # Defaults to 3 as these are not very useful.
 #rocksdb_max_log_files = 3

src/config/mod.rs

@@ -228,6 +228,10 @@ pub(crate) struct Config {
 	pub(crate) rocksdb_read_only: bool,
 	#[serde(default)]
 	pub(crate) rocksdb_periodic_cleanup: bool,
+	#[serde(default)]
+	pub(crate) rocksdb_compaction_prio_idle: bool,
+	#[serde(default = "true_fn")]
+	pub(crate) rocksdb_compaction_ioprio_idle: bool,
 
 	pub(crate) emergency_password: Option<String>,
 
@@ -706,9 +710,22 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 			),
 			#[cfg(feature = "rocksdb")]
 			("RocksDB Recovery Mode", &self.rocksdb_recovery_mode.to_string()),
+			#[cfg(feature = "rocksdb")]
 			("RocksDB Repair Mode", &self.rocksdb_repair.to_string()),
+			#[cfg(feature = "rocksdb")]
 			("RocksDB Read-only Mode", &self.rocksdb_read_only.to_string()),
+			#[cfg(feature = "rocksdb")]
 			("RocksDB Periodic Cleanup", &self.rocksdb_periodic_cleanup.to_string()),
+			#[cfg(feature = "rocksdb")]
+			(
+				"RocksDB Compaction Idle Priority",
+				&self.rocksdb_compaction_prio_idle.to_string(),
+			),
+			#[cfg(feature = "rocksdb")]
+			(
+				"RocksDB Compaction Idle IOPriority",
+				&self.rocksdb_compaction_ioprio_idle.to_string(),
+			),
 			("Prevent Media Downloads From", {
 				let mut lst = vec![];
 				for domain in &self.prevent_media_downloads_from {

src/database/rocksdb/mod.rs

@@ -41,9 +41,9 @@ fn open(config: &Config) -> Result<Self> {
 		let mut col_cache = HashMap::new();
 		col_cache.insert("primary".to_owned(), Cache::new_lru_cache(col_cache_capacity_bytes));
 
-		let db_env = Env::new()?;
+		let mut db_env = Env::new()?;
 		let row_cache = Cache::new_lru_cache(row_cache_capacity_bytes);
-		let db_opts = db_options(config, &db_env, &row_cache, col_cache.get("primary").expect("cache"));
+		let db_opts = db_options(config, &mut db_env, &row_cache, col_cache.get("primary").expect("cache"));
 
 		let load_time = std::time::Instant::now();
 		if config.rocksdb_repair {

src/database/rocksdb/opts.rs

@@ -14,7 +14,7 @@
 /// resulting value. Note that we require special per-column options on some
 /// columns, therefor columns should only be opened after passing this result
 /// through cf_options().
-pub(crate) fn db_options(config: &Config, env: &Env, row_cache: &Cache, col_cache: &Cache) -> Options {
+pub(crate) fn db_options(config: &Config, env: &mut Env, row_cache: &Cache, col_cache: &Cache) -> Options {
 	let mut opts = Options::default();
 
 	// Logging
@@ -30,6 +30,9 @@ pub(crate) fn db_options(config: &Config, env: &Env, row_cache: &Cache, col_cach
 	opts.set_max_background_jobs(threads.try_into().unwrap());
 	opts.set_max_subcompactions(threads.try_into().unwrap());
 	opts.set_max_file_opening_threads(0);
+	if config.rocksdb_compaction_prio_idle {
+		env.lower_thread_pool_cpu_priority();
+	}
 
 	// IO
 	opts.set_manual_wal_flush(true);
@@ -41,6 +44,9 @@ pub(crate) fn db_options(config: &Config, env: &Env, row_cache: &Cache, col_cach
 		opts.set_skip_stats_update_on_db_open(true);
 		//opts.set_max_file_opening_threads(threads.try_into().unwrap());
 	}
+	if config.rocksdb_compaction_ioprio_idle {
+		env.lower_thread_pool_io_priority();
+	}
 
 	// Blocks
 	let mut table_opts = table_options(config);