Runtime worker threads (#7089)

* std variant * principal work * format and naming * format and naming continued * working nested fork * add comment * naming and tabs * line width * fix wording * address review * refactor dynamic dispatch * update wasmtime * some care * move ext * more refactor * doc effort * simplify * doc effort * tests and docs * address review * naming * explain some args * add example * unwinding for native and tests * rename stray * fix refs * fix tests * fix warnings * stray naming * fixes and comments * Update primitives/io/src/tasks.rs Co-authored-by: cheme <emericchevalier.pro@gmail.com> * make examples "compile" * dyn_dispatch -> spawn_call * fix impl * address review * Update primitives/io/src/lib.rs Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com> * Update primitives/io/src/tasks.rs Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com> * Update primitives/io/src/async_externalities.rs Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com> * Update primitives/io/src/tasks.rs Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com> * Update frame/example-parallel/src/lib.rs Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com> * fix compilation * Update client/executor/common/src/wasm_runtime.rs Co-authored-by: Sergei Shulepov <sergei@parity.io> * address review * Update client/executor/wasmtime/src/instance_wrapper.rs Co-authored-by: Sergei Shulepov <sergei@parity.io> * Update client/executor/src/native_executor.rs Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com> * Update primitives/io/src/tasks.rs Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com> * Update client/executor/src/native_executor.rs Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com> * Update primitives/io/src/tasks.rs Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com> * Update client/executor/wasmtime/src/instance_wrapper.rs Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com> * address some issues * address more issues * wasm_only interface * define sp_tasks * avoid anyhow * fix example Co-authored-by: cheme <emericchevalier.pro@gmail.com> Co-authored-by: Kian Paimani <5588131+kianenigma@users.noreply.github.com> Co-authored-by: Sergei Shulepov <sergei@parity.io> Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>
2026-04-27 06:57:58 +00:00 · 2020-10-20 05:41:51 -07:00
parent 203acda659
commit a062bc2f1d
26 changed files with 1498 additions and 112 deletions
@@ -0,0 +1,247 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2020 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Runtime tasks.
+//!
+//! Contains runtime-usable functions for spawning parallel purely computational tasks.
+//!
+//! NOTE: This is experimental API.
+//! NOTE: When using in actual runtime, make sure you don't produce unbounded parallelism.
+//! So this is bad example to use it:
+//! ```rust
+//!    fn my_parallel_computator(data: Vec<u8>) -> Vec<u8> {
+//!        unimplemented!()
+//!    }
+//!    fn test(dynamic_variable: i32) {
+//!        for _ in 0..dynamic_variable { sp_tasks::spawn(my_parallel_computator, vec![]); }
+//!    }
+//! ```
+//!
+//! While this is a good example:
+//! ```rust
+//!    use codec::Encode;
+//!    static STATIC_VARIABLE: i32 = 4;
+//!
+//!    fn my_parallel_computator(data: Vec<u8>) -> Vec<u8> {
+//!        unimplemented!()
+//!    }
+//!
+//!    fn test(computation_payload: Vec<u8>) {
+//!        let parallel_tasks = (0..STATIC_VARIABLE).map(|idx|
+//!            sp_tasks::spawn(my_parallel_computator, computation_payload.chunks(10).nth(idx as _).encode())
+//!        );
+//!    }
+//! ```
+//!
+//! When allowing unbounded parallelism, malicious transactions can exploit it and partition
+//! network consensus based on how much resources nodes have.
+//!
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+#[cfg(feature = "std")]
+mod async_externalities;
+
+#[cfg(feature = "std")]
+pub use async_externalities::{new_async_externalities, AsyncExternalities};
+
+#[cfg(feature = "std")]
+mod inner {
+	use std::{panic::AssertUnwindSafe, sync::mpsc};
+	use sp_externalities::ExternalitiesExt as _;
+	use sp_core::traits::TaskExecutorExt;
+
+	/// Task handle (wasm).
+	///
+	/// This can be `join`-ed to get (blocking) the result of
+	/// the spawned task execution.
+	#[must_use]
+	pub struct DataJoinHandle {
+		receiver: mpsc::Receiver<Vec<u8>>,
+	}
+
+	impl DataJoinHandle {
+		/// Join handle returned by `spawn` function
+		pub fn join(self) -> Vec<u8> {
+			self.receiver.recv().expect("Spawned runtime task terminated before sending result.")
+		}
+	}
+
+	/// Spawn new runtime task (native).
+	pub fn spawn(entry_point: fn(Vec<u8>) -> Vec<u8>, data: Vec<u8>) -> DataJoinHandle {
+		let scheduler = sp_externalities::with_externalities(|mut ext| ext.extension::<TaskExecutorExt>()
+			.expect("No task executor associated with the current context!")
+			.clone()
+		).expect("Spawn called outside of externalities context!");
+
+		let (sender, receiver) = mpsc::channel();
+		let extra_scheduler = scheduler.clone();
+		scheduler.spawn("parallel-runtime-spawn", Box::pin(async move {
+			let result = match crate::new_async_externalities(extra_scheduler) {
+				Ok(mut ext) => {
+					let mut ext = AssertUnwindSafe(&mut ext);
+					match std::panic::catch_unwind(move || {
+						sp_externalities::set_and_run_with_externalities(
+							&mut **ext,
+							move || entry_point(data),
+						)
+					}) {
+						Ok(result) => result,
+						Err(panic) => {
+							log::error!(
+								target: "runtime",
+								"Spawned task panicked: {:?}",
+								panic,
+							);
+
+							// This will drop sender without sending anything.
+							return;
+						}
+					}
+				},
+				Err(e) => {
+					log::error!(
+						target: "runtime",
+						"Unable to run async task: {}",
+						e,
+					);
+
+					return;
+				},
+			};
+
+			let _ = sender.send(result);
+		}));
+
+		DataJoinHandle { receiver }
+	}
+}
+
+#[cfg(not(feature = "std"))]
+mod inner {
+	use core::mem;
+	use sp_std::prelude::*;
+
+	/// Dispatch wrapper for wasm blob.
+	///
+	/// Serves as trampoline to call any rust function with (Vec<u8>) -> Vec<u8> compiled
+	/// into the runtime.
+	///
+	/// Function item should be provided with `func_ref`. Argument for the call
+	/// will be generated from bytes at `payload_ptr` with `payload_len`.
+	///
+	/// NOTE: Since this dynamic dispatch function and the invoked function are compiled with
+	/// the same compiler, there should be no problem with ABI incompatibility.
+	extern "C" fn dispatch_wrapper(func_ref: *const u8, payload_ptr: *mut u8, payload_len: u32) -> u64 {
+		let payload_len = payload_len as usize;
+		let output = unsafe {
+			let payload = Vec::from_raw_parts(payload_ptr, payload_len, payload_len);
+			let ptr: fn(Vec<u8>) -> Vec<u8> = mem::transmute(func_ref);
+			(ptr)(payload)
+		};
+		sp_runtime_interface::pack_ptr_and_len(output.as_ptr() as usize as _, output.len() as _)
+	}
+
+	/// Spawn new runtime task (wasm).
+	pub fn spawn(entry_point: fn(Vec<u8>) -> Vec<u8>, payload: Vec<u8>) -> DataJoinHandle {
+		let func_ptr: usize = unsafe { mem::transmute(entry_point) };
+
+		let handle = sp_io::runtime_tasks::spawn(
+			dispatch_wrapper as usize as _,
+			func_ptr as u32,
+			payload,
+		);
+		DataJoinHandle { handle }
+	}
+
+	/// Task handle (wasm).
+	///
+	/// This can be `join`-ed to get (blocking) the result of
+	/// the spawned task execution.
+	#[must_use]
+	pub struct DataJoinHandle {
+		handle: u64,
+	}
+
+	impl DataJoinHandle {
+		/// Join handle returned by `spawn` function
+		pub fn join(self) -> Vec<u8> {
+			sp_io::runtime_tasks::join(self.handle)
+		}
+	}
+}
+
+pub use inner::{DataJoinHandle, spawn};
+
+#[cfg(test)]
+mod tests {
+
+	use super::*;
+
+	fn async_runner(mut data: Vec<u8>) -> Vec<u8> {
+		data.sort();
+		data
+	}
+
+	fn async_panicker(_data: Vec<u8>) -> Vec<u8> {
+		panic!("panic in async panicker!")
+	}
+
+	#[test]
+	fn basic() {
+		sp_io::TestExternalities::default().execute_with(|| {
+			let a1 = spawn(async_runner, vec![5, 2, 1]).join();
+			assert_eq!(a1, vec![1, 2, 5]);
+		})
+	}
+
+	#[test]
+	fn panicking() {
+		let res = sp_io::TestExternalities::default().execute_with_safe(||{
+			spawn(async_panicker, vec![5, 2, 1]).join();
+		});
+
+		assert!(res.unwrap_err().contains("Closure panicked"));
+	}
+
+	#[test]
+	fn many_joins() {
+		sp_io::TestExternalities::default().execute_with_safe(|| {
+			// converges to 1 only after 1000+ steps
+			let mut running_val = 9780657630u64;
+			let mut data = vec![];
+			let handles = (0..1024).map(
+				|_| {
+					running_val = if running_val % 2 == 0 {
+						running_val / 2
+					} else {
+						3 * running_val + 1
+					};
+					data.push(running_val as u8);
+					(spawn(async_runner, data.clone()), data.clone())
+				}
+			).collect::<Vec<_>>();
+
+			for (handle, mut data) in handles {
+				let result = handle.join();
+				data.sort();
+
+				assert_eq!(result, data);
+			}
+		}).expect("Failed to run with externalities");
+	}
+}