Make plotting/replotting thread pools distinct for farms to avoid stack overflow, still protected by semaphores

crates/subspace-farmer/src/bin/subspace-farmer/commands/farm.rs

@@ -11,7 +11,6 @@ use futures::stream::FuturesUnordered;
 use futures::{FutureExt, StreamExt};
 use lru::LruCache;
 use parking_lot::Mutex;
-use rayon::ThreadPoolBuilder;
 use std::fs;
 use std::net::SocketAddr;
 use std::num::{NonZeroU8, NonZeroUsize};
@@ -29,9 +28,7 @@ use subspace_farmer::utils::farmer_piece_getter::FarmerPieceGetter;
 use subspace_farmer::utils::piece_validator::SegmentCommitmentPieceValidator;
 use subspace_farmer::utils::readers_and_pieces::ReadersAndPieces;
 use subspace_farmer::utils::ss58::parse_ss58_reward_address;
-use subspace_farmer::utils::{
-    run_future_in_dedicated_thread, tokio_rayon_spawn_handler, AsyncJoinOnDrop,
-};
+use subspace_farmer::utils::{run_future_in_dedicated_thread, AsyncJoinOnDrop};
 use subspace_farmer::{Identity, NodeClient, NodeRpcClient};
 use subspace_farmer_components::plotting::PlottedSector;
 use subspace_metrics::{start_prometheus_metrics_server, RegistryAdapter};
@@ -134,13 +131,21 @@ pub(crate) struct FarmingArgs {
     /// the system
     #[arg(long, default_value_t = available_parallelism())]
     farming_thread_pool_size: usize,
-    /// Size of thread pool used for plotting, defaults to number of CPU cores available in the
-    /// system. This thread pool is global for all farms and generally doesn't need to be changed.
+    /// Size of PER FARM thread pool used for plotting, defaults to number of CPU cores available
+    /// in the system.
+    ///
+    /// NOTE: The fact that this parameter is per farm doesn't mean farmer will plot multiple
+    /// sectors concurrently, see `--sector-downloading-concurrency` and
+    /// `--sector-encoding-concurrency` options.
     #[arg(long, default_value_t = available_parallelism())]
     plotting_thread_pool_size: usize,
-    /// Size of thread pool used for replotting, typically smaller pool than for plotting to not
-    /// affect farming as much, defaults to half of the number of CPU cores available in the system.
-    /// This thread pool is global for all farms and generally doesn't need to be changed.
+    /// Size of PER FARM thread pool used for replotting, typically smaller pool than for plotting
+    /// to not affect farming as much, defaults to half of the number of CPU cores available in the
+    /// system.
+    ///
+    /// NOTE: The fact that this parameter is per farm doesn't mean farmer will replot multiple
+    /// sectors concurrently, see `--sector-downloading-concurrency` and
+    /// `--sector-encoding-concurrency` options.
     #[arg(long, default_value_t = available_parallelism() / 2)]
     replotting_thread_pool_size: usize,
 }
@@ -423,21 +428,6 @@ where
         None => farmer_app_info.protocol_info.max_pieces_in_sector,
     };
 
-    let plotting_thread_pool = Arc::new(
-        ThreadPoolBuilder::new()
-            .thread_name(move |thread_index| format!("plotting#{thread_index}"))
-            .num_threads(plotting_thread_pool_size)
-            .spawn_handler(tokio_rayon_spawn_handler())
-            .build()?,
-    );
-    let replotting_thread_pool = Arc::new(
-        ThreadPoolBuilder::new()
-            .thread_name(move |thread_index| format!("replotting#{thread_index}"))
-            .num_threads(replotting_thread_pool_size)
-            .spawn_handler(tokio_rayon_spawn_handler())
-            .build()?,
-    );
-
     let downloading_semaphore = Arc::new(Semaphore::new(sector_downloading_concurrency.get()));
     let encoding_semaphore = Arc::new(Semaphore::new(sector_encoding_concurrency.get()));
 
@@ -467,8 +457,8 @@ where
                 encoding_semaphore: Arc::clone(&encoding_semaphore),
                 farm_during_initial_plotting,
                 farming_thread_pool_size,
-                plotting_thread_pool: Arc::clone(&plotting_thread_pool),
-                replotting_thread_pool: Arc::clone(&replotting_thread_pool),
+                plotting_thread_pool_size,
+                replotting_thread_pool_size,
                 plotting_delay: Some(plotting_delay_receiver),
             },
             disk_farm_index,

crates/subspace-farmer/src/single_disk_farm.rs

@@ -26,7 +26,7 @@ use futures::{select, FutureExt, StreamExt};
 use parity_scale_codec::{Decode, Encode};
 use parking_lot::Mutex;
 use rayon::prelude::*;
-use rayon::{ThreadPool, ThreadPoolBuilder};
+use rayon::ThreadPoolBuilder;
 use serde::{Deserialize, Serialize};
 use static_assertions::const_assert;
 use std::fs::{File, OpenOptions};
@@ -268,11 +268,11 @@ pub struct SingleDiskFarmOptions<NC, PG> {
     /// Thread pool size used for farming (mostly for blocking I/O, but also for some
     /// compute-intensive operations during proving)
     pub farming_thread_pool_size: usize,
-    /// Thread pool used for plotting
-    pub plotting_thread_pool: Arc<ThreadPool>,
-    /// Thread pool used for replotting, typically smaller pool than for plotting to not affect
+    /// Thread pool size used for plotting
+    pub plotting_thread_pool_size: usize,
+    /// Thread pool size used for replotting, typically smaller pool than for plotting to not affect
     /// farming as much
-    pub replotting_thread_pool: Arc<ThreadPool>,
+    pub replotting_thread_pool_size: usize,
     /// Notification for plotter to start, can be used to delay plotting until some initialization
     /// has happened externally
     pub plotting_delay: Option<oneshot::Receiver<()>>,
@@ -592,8 +592,8 @@ impl SingleDiskFarm {
             downloading_semaphore,
             encoding_semaphore,
             farming_thread_pool_size,
-            plotting_thread_pool,
-            replotting_thread_pool,
+            plotting_thread_pool_size,
+            replotting_thread_pool_size,
             plotting_delay,
             farm_during_initial_plotting,
         } = options;
@@ -877,6 +877,50 @@ impl SingleDiskFarm {
 
             move || {
                 let _span_guard = span.enter();
+                let plotting_thread_pool = match ThreadPoolBuilder::new()
+                    .thread_name(move |thread_index| {
+                        format!("plotting-{disk_farm_index}.{thread_index}")
+                    })
+                    .num_threads(plotting_thread_pool_size)
+                    .spawn_handler(tokio_rayon_spawn_handler())
+                    .build()
+                    .map_err(PlottingError::FailedToCreateThreadPool)
+                {
+                    Ok(thread_pool) => thread_pool,
+                    Err(error) => {
+                        if let Some(error_sender) = error_sender.lock().take() {
+                            if let Err(error) = error_sender.send(error.into()) {
+                                error!(
+                                    %error,
+                                    "Plotting failed to send error to background task",
+                                );
+                            }
+                        }
+                        return;
+                    }
+                };
+                let replotting_thread_pool = match ThreadPoolBuilder::new()
+                    .thread_name(move |thread_index| {
+                        format!("replotting-{disk_farm_index}.{thread_index}")
+                    })
+                    .num_threads(replotting_thread_pool_size)
+                    .spawn_handler(tokio_rayon_spawn_handler())
+                    .build()
+                    .map_err(PlottingError::FailedToCreateThreadPool)
+                {
+                    Ok(thread_pool) => thread_pool,
+                    Err(error) => {
+                        if let Some(error_sender) = error_sender.lock().take() {
+                            if let Err(error) = error_sender.send(error.into()) {
+                                error!(
+                                    %error,
+                                    "Plotting failed to send error to background task",
+                                );
+                            }
+                        }
+                        return;
+                    }
+                };
 
                 let plotting_fut = async move {
                     if start_receiver.recv().await.is_err() {
@@ -984,6 +1028,7 @@ impl SingleDiskFarm {
             let span = span.clone();
 
             move || {
+                let _span_guard = span.enter();
                 let thread_pool = match ThreadPoolBuilder::new()
                     .thread_name(move |thread_index| {
                         format!("farming-{disk_farm_index}.{thread_index}")
@@ -1008,6 +1053,7 @@ impl SingleDiskFarm {
                 };
 
                 let handle = Handle::current();
+                let span = span.clone();
                 thread_pool.install(move || {
                     let _span_guard = span.enter();
 

crates/subspace-farmer/src/single_disk_farm/plotting.rs

@@ -9,7 +9,7 @@ use futures::channel::{mpsc, oneshot};
 use futures::{select, FutureExt, SinkExt, StreamExt};
 use lru::LruCache;
 use parity_scale_codec::Encode;
-use rayon::ThreadPool;
+use rayon::{ThreadPool, ThreadPoolBuildError};
 use std::collections::HashMap;
 use std::fs::File;
 use std::io;
@@ -81,12 +81,15 @@ pub enum PlottingError {
     /// Farm is shutting down
     #[error("Farm is shutting down")]
     FarmIsShuttingDown,
-    /// I/O error occurred
-    #[error("I/O error: {0}")]
-    Io(#[from] io::Error),
     /// Low-level plotting error
     #[error("Low-level plotting error: {0}")]
     LowLevel(#[from] plotting::PlottingError),
+    /// I/O error occurred
+    #[error("I/O error: {0}")]
+    Io(#[from] io::Error),
+    /// Failed to create thread pool
+    #[error("Failed to create thread pool: {0}")]
+    FailedToCreateThreadPool(#[from] ThreadPoolBuildError),
 }
 
 pub(super) struct PlottingOptions<NC, PG> {
@@ -111,8 +114,8 @@ pub(super) struct PlottingOptions<NC, PG> {
     /// Semaphore for part of the plotting when farmer encodes downloaded sector, should typically
     /// allow one permit at a time for efficient CPU utilization
     pub(crate) encoding_semaphore: Arc<Semaphore>,
-    pub(super) plotting_thread_pool: Arc<ThreadPool>,
-    pub(super) replotting_thread_pool: Arc<ThreadPool>,
+    pub(super) plotting_thread_pool: ThreadPool,
+    pub(super) replotting_thread_pool: ThreadPool,
     pub(super) stop_receiver: broadcast::Receiver<()>,
 }