Rust channel vs mutex

Rust channel vs mutex. The channel function will return a (Sender, Receiver) tuple where all sends will be asynchronous (they never block). 4 days ago · This mutex will block threads waiting for the lock to become available. Apr 18, 2023 · While mutexes in Rust can prevent data races and ensure thread safety, they can also lead to mutex poisoning. Imagine multiple rivers and streams flowing Mutex wraps around any type of data and provides a lock method that returns a guard object. Multithreading is a crucial concept in modern software development that enables efficient concurrent execution of tasks. For a mutex, this means that the lock and try_lock methods return a Result which indicates whether a mutex has been poisoned or not. However, I'm not sure to understand how Rust figures this out. Arc<Vec<Mutex<T>>> allows one to share some number of Mutex<T> 's without having to Arc each one individually, or maybe one wants to have some abstraction around a Mutex, and so wrap it in a struct: struct Wrapped {. In other words, a mutex is a way to prevent multiple threads from accessing a certain resource at the same time. Jul 2, 2021 · A type is often labeled (only via documentation) as "thread-safe" or "not thread-safe. In Rust, a mutex protects specific data relying on the borrow-checking mechanism used elsewhere in the language. Kanal utilizes a specially tuned mutex for its channel locking mechanism, made possible by the predictable internal lock time of the channel. The sync_channel function will return a (SyncSender, Receiver) tuple Nov 1, 2019 · As you can see, the map is of “cache-key” to an Arc to a tuple of Mutex<HttpCacheEntryState>, and a Condvar. Modified 7 years, 9 months ago. :: Sender. But it helps you by providing atomics. Go is pragmatic in letting you use the tools that solve your problem best and not forcing you into one style of code. Finally my memories of Arc and Mutex are a bit stronger, I want to send and receive messages in the most efficient way. We can get rid of once_cell and just initialise the global mutex with a content which is known at compile-time. unwrap(); *num = 6; } This code represents a simple Mutex usage. They may be moved to different tasks. I read a article that shared tokio::receiver inside Arc<Mutex> but I search and found async_channel crate is recommended for mpmc. But even after making this change, guard is pointing inside mutex, so you're effectively creating a self-referential data structure, and that won't compile. When all Sender s or all Receiver s are dropped, the channel becomes closed. This is done by forcing a fair lock whenever a lock operation is starved for longer than 0. Go channels are appealing because they provide built-in thread safety and encourage single-threaded Jun 13, 2019 · 24. It is known that you can build one with a mutex and a conditional variable. In the code above, tx stands for transmitter, and rx stands for receiver. Do not store the receiver in the mutex, only the sender. " In Rust, the Send and Sync traits allow us to express much more granular ideas about thread safety, and communicate them much more clearly. Apr 19, 2018 · let mut locked = vec. On the other hand channels are for orchestrating computations between goroutines. This, in turn, will block other tasks from processing. In order to share access to this database between tasks, there are two DatabaseHandle implementations: one based on mpsc and oneshot channels and one based on Arc<Mutex<_>>. Goroutine A puts a value into the channel: var v T // v is a value of type T. A futures-aware mutex. ShardedLock, a sharded reader-writer lock with fast concurrent reads. Don’t be afraid to use a sync. Table of contents: Quick Recap! Actual MP in MPSC. Dec 28, 2023 · The mutex ensures exclusive access to the counter, preventing data races but potentially leading to thread contention. Viewed 6k times. Mutex 有下面几个特征：. To access the data in a mutex, a thread must first signal that it wants access by asking to acquire the mutex’s lock. Condvar, on the other hand, allows threads to wait for a particular condition to be met. The channel is created with a capacity of 32. I haven't personally benchmarked mpsc against Arc<Mutex<VecDeque<T>>>, and I don't think anyone else has, either. making multiple, contiguous operations atomic with proper locking of Mutex' or RwLocks). Oct 22, 2023 · The below Rust code implements a simple "database" that stores a single u32 which can be written to and read from asynchronously. unwrap(). When it comes to concurrency in Rust, you can spawn child threads, pass data between threads using channels like Go, or share state between thread using Arc and mutex. An unbounded channel is likely implemented via a linked list, which is more flexible but more expensive. Meanwhile in the MPSC version, you are folding with the HashMap directly, so locking happens much less frequently, namely only when you send something through the channel. 直到锁令牌得到。. Sep 30, 2023 · To create a channel in Rust, you use the channel function. The two handles are used separately. It's a straightforward, foolproof approach to concurrency. Do be mindful of the cost of the dropping the previous Arc<T> when swapping a new one oneshot. You'll probably need to wrap shared collections in Arc to have them live Mutex<T> implements both Send and Sync iff (if and only if) T implements Send. 0. Meanwhile the docs also mention the async mutex uses a sync mutex internally. channel; const N: usize = 10; // Spawn a few threads to increment a shared variable (non A beginning introduction to the concept of Shared-State concurrency! In this article, we have presented the idea of MPSC messages + Shared-State Concurrency in Rust along with Mutex. Each mutex has a type parameter which represents the data that it is protecting. Jan 25, 2023 · Kanal utilizes a specially tuned mutex for its channel locking mechanism, made possible by the predictable internal lock time of the channel. When this structure is dropped (falls out of scope), the lock will be unlocked. This function is similar to Rust’s channel constructor found in the standard library. Data transfer represents copying a value of some type T. If a panic occurs in any reader, then the lock will not be poisoned. Rustでは所有権という概念があります. Objectives Is my implementation correct? Why not? What is missing for it to be production ready¹? As I say on the docs of the snippet, the solution is not Nov 20, 2017 · This is not valid to have because the value inside the Mutex isn't behind a pointer, thus making the whole type unsized. You need to specify the lifetime <'a> in the function. Dec 21, 2019 · The Rust ownership model can be used to enforce this non-overlapping use. To use a Mutex, you lock it, perform your operation, and then unlock it. [ −] Oneshot spsc (single producer, single consumer) channel. Apr 29, 2024 · The channel function will return a (Sender, Receiver) tuple where all sends will be asynchronous (they never block). If you can't use them (as they are only available for primitive types) you still have to know how to deal with that (e. unwrap(); locked. This has a few nice outcomes. When you do this, wherever you call it (in the main function) implies the calling closure has lifetime <'a>. In ThreadPool::new, we put the receiving end of the channel in an Arc and a Mutex. Using Rayon with Mutex? Please help. Hi, tokio has it's own implementation of mpsc queue, which differs from implementation in futures. Rust's MPSC channel offers a powerful tool for ensuring data integrity and synchronization across threads, making it an invaluable asset for developers tackling complex Aug 16, 2016 · How do the channels work in Rust By Example? Asked 7 years, 9 months ago. lewis421 February 28, 2021, 5:31pm 1. Oct 16, 2022 · As stated by Chayim Friedman in a comment, since Rust 1. clone() , and it passes away into oblivion at the semicolon. Feb 28, 2024 · A Mutex (short for mutual exclusion) is a concurrency primitive that is used to protect shared data. Tokio’s Mutex operates on a guaranteed FIFO basis. The guard object grants you exclusive access to the data, and it automatically unlocks the mutex when it Oct 29, 2019 · One possible type that can be send is a String while the other is a struct I've defined. g. Meaning each channel instance can only transport a single message. Parker, a thread parking primitive. Mutex 通过 . This means that the order in which tasks call the lock method is the exact order in which they will acquire the A bounded channel operates like an array / vec, in which a fixed capacity is allocated. The problem arises with the borrow-checker. docs. #[auto_log] Rust vs C++. Apr 29, 2024 · mpsc. A read-write lock counterpart: RwLock. Here I wanted to get some validation of my solution. When a channel is closed, no more messages can be sent, but remaining messages can still be received. Rust provides a Mutex type in the standard library’s std::sync module. Two popular languages, Go and Rust, have brought unique Mar 26, 2022 · Introduction Semaphores are a vital concurrency device. Creating the channel returns two values, a sender and a receiver. The lock operation returns a “guard” value. Oct 8, 2023 · Mutex Vs. 同时只有一个线程的 Mutex 对象获取到锁；. The ones from crossbeam-channel can be shared. 63, it can be easier to work with global mutable singletons, although it's still preferable to avoid global variables in most cases. They play an integral role in designing systems where different parts need to communicate concurrently, efficiently, and safely. Channels allow a unidirectional flow of information between two end-points: the Sender and the Receiver. You can also see that the map as a whole is protected by a Mutex as well. Note the use of the mut keyword to designate mutable variables: use std::sync::{Arc, Mutex}; use std::thread; use std::sync::mpsc::channel; const N: usize = 10; // Spawn a few threads to increment a shared variable (non-atomically), and // let the main thread know once all Oct 14, 2015 · However, moving away from the Pointer<Mutex<>> pattern, it can be useful to have the mutex and the sharing separated, e. For each new worker, we clone the Arc to bump the reference count so the workers can share ownership of the receiving end. We create a new channel using the mpsc::channel function; mpsc stands for multiple producer, single consumer. For reentrant mutex, this API doesn't work: you can't return &mut T because reentrancy allows one to get the second &mut T, violating aliasing guarantees. In Rust, a Mutex allows only one thread to access data at a time. You don't need an Arc to use a Mutex. Messages can be sent through this channel with send. This function returns a tuple containing a transmitter and a receiver. The first runs into the mutex fast-path, whereas the second sees that the mutex is locked and actually needs to call into the runtime, synchronize and go to sleep and everything. rs async_channel - Rust. Shared-State Concurrency Overview. I want it to be a space economy simlation, which basically means I have a state, that is periodically updated (let's say every second) with the player able to change some of the parameters. The data protected by the mutex can be accessed through this guard via its Deref and DerefMut Dec 12, 2019 · The idiomatic Rust API for a mutext is to have a lock method which, given a &Mutex<T>, returns an &mut T (apropriately wrapped into a guard object). As a general guide, though: Channel Sep 28, 2020 · Tokio::sync:mpsc vs futures::channel::mpsc. You can ignore the fact that the server will also echo messages received to the peers as well. Sep 29, 2015 · And of course there is also the distinction between a single-process (userland) mutex and a cross-process (kernel) mutex; I didn't want to get into that level of technical detail in this answer, which is a high-level summary rather than an in-depth explanation. Instead, I'd implement the trait for a Mutex of any kind that implements the same trait. org) 有識者の方に意訳して頂きました。 あるスレッドがMutexを持ったままパニックを起こした場合、唐突にロックが解除されるため、含まれるデータの一貫性が失われてしまうおそれがある。 Jun 8, 2021 · In the Arc+Mutex version, you are repeatedly locking the mutex around the hash map, for the insertion of every single character. Here is a simple example of using a Mutex: use std::sync::Mutex; use std::thread; let m = Mutex::new(5); {. I am attempting to do just that for learning purposes. I am trying to learn rust by building a game. Apr 23, 2021 · Remember that Mutex::lock(&self) takes a reference to the Mutex. push(x); }); } Since Rayon blocks until the parallel iteration completes, I understand that there is no need to keep track of a reference count. Sends a message along this channel. Jun 27, 2022 · An asynchronous, infinitely buffered channel. 1. Mutexes work by using atomic operations to maintain a lock on a resource. await. Listing 20-18: Sharing the receiving end of the channel between the workers by using Arc and Mutex. try_lock() 来尝试得到锁令牌，被保护的对象，必须 Nov 5, 2023 · In essence, channels in Rust (and similar constructs in other languages) are more than just data transfer mechanisms. e. The mutex can be statically initialized or created by the new constructor. 同期の説明. channel, multi-producer multi-consumer channels for message passing. There are a plethora of patterns that can be done using channels that are meaningless when we talk about a Mutex. This is an unbounded sender, so this function differs from Sink::send by ensuring the return type reflects that the channel is always ready to receive messages. there is a limit to how many messages it can hold at a time. A sync. You cannot use crossbeam in async code due to the issues described in this article . Nov 17, 2023 · Choosing RwLock Over Mutex: A Consideration of Context In the Rust ecosystem, we often use Mutex for safe, exclusive access to data across multiple threads. May 21, 2022 · So this is comparing Arc<RefCell<T>> not only with Arc<Mutex<T>> but also with Rc<RefCell<T>>. The latter gives much finer control and my question was about that - is there a facility similar to std::lock of c++. This mutex provides no fairness guarantees. Part 3. The crossbeam-channel provides this type of functionality and is the most popular crate (that I know of) for channels. WaitGroup, for synchronizing the beginning or end of some computation. In the code I sent, it shows how you can do that. Pointer, Smart Pointer, Reference Counting and Atomic Reference Counting. An async multi-producer multi-consumer channel, where each message can be received by only one of all existing An RwLock, like Mutex, will become poisoned on a panic. The locking mechanism uses eventual fairness to ensure locking will be fair on average without sacrificing performance. len() to retrieve the shard Oct 5, 2023 · Tokio docs recommend using sync mutex where they are feasible for better performance. I am quite confused by the output of the channel chapter of Rust by Example: use std::sync::mpsc::{Sender, Receiver}; use std::sync::mpsc; use std::thread; static NTHREADS: i32 = 3; fn main() { Create a shared mpsc::channel whose tx's are cloned for each thread and a single thread listens to rx channel and aggregates all IDs in a thread-local vector. 63 Mutex::new() is const. await points. ミューテックスの管理は、正しく行うのに著しく技巧を要することがあるので、多くの人がチャンネルに熱狂的になるわけです。 しかしながら、Rustの型システムと所有権規則のおかげで、ロックとアンロックをおかしくすることはありません。 Mutex<T>のAPI Mar 17, 2017 · A clear example of Mutex use can be found in the Mutex documentation. Dec 6, 2021 · ここでは、スレッドでメッセージを受け取るreceiverをArcとMutexというオブジェクトでラッパーしています。 なぜそうしないといけないのかを説明します。 Arc. The API differs from C in three ways: Mutex contains the data it guards: the full name of the type is Mutex<T>, for some guarded type T that you choose. The sync_channel function will return a (SyncSender, Receiver) tuple where the Mar 8, 2023 · Mutex in std::sync - Rust (rust-lang. If you are running a program and block 'a' produces a single 3d array called BIG and block 'b' uses rayon to, in a multi-threaded loop, access and assign 3d array's from BIG using array. The mpsc in the import stands for "multiple producer, single consumer". Dec 15, 2022 · You can use the ArcSwapOption<T> to have the equivalent of an Atomic<Option<Arc<T>>>, and the consumer can simply perform a let new = atomic. Creates a new one-shot channel for sending a single value across asynchronous tasks. If you are actually interested in the Mutex is an abbreviation for mutual exclusion, as in, a mutex allows only one thread to access some data at any given time. In short, the way Rust’s standard library implements channels means a channel can have multiple sending ends that produce values but only one receiving end that consumes those values. Mutex 会等待获取锁令牌 (token)，在等待过程中，会阻塞线程。. Sep 8, 2016 · It's really a difference betwen Arc<Mutex ing the whole struct vs Arc<Mutex ing individual fields. Both sides are cloneable and can be shared among multiple threads. select (Axis (2), & [x,y,z]) is Aug 14, 2020 · The items pointed-to by the MutexGuard last for static because you have it inside a lazy_static block. You likely want mpmc (Multiple Producer, Multiple Consumer) channels instead. Nov 15, 2023 · I created a web socket server in Rust, using a server example from tokio-tungstenite. I would like to better understand the trade-offs between the two since they both provide the Oct 18, 2023 · A common synchronization primitive in many languages is the Mutex. Jan 15, 2022 · I need a ( Multi-Producer, Multi_Consumer ) channel but tokio have mpsc. swap(None); then check if new is None (nothing new) or Some(Arc<T>) in which case it received an updated configuration. However, switching to tokio::sync::Mutex usually does not help as the asynchronous mutex uses a synchronous mutex internally. use std::sync::Mutex; let m = Mutex::new(5); { let mut num = m. Rust provides asynchronous channels for communication between threads. channel; const N: usize = 10; // Spawn a few threads to increment a shared variable (non Apr 22, 2023 · The PR that did this merge is Merge crossbeam-channel into `std::sync::mpsc` by ibraheemdev · Pull Request #93563 · rust-lang/rust · GitHub and it has some context on why they did it. And fn lock(&Mutext<T>) -> &T signature is Feb 28, 2021 · Please help - The Rust Programming Language Forum. While Mutex allows exclusive access to one thread, RwLock permits multiple readers or one writer. It works best if you can split your problem into sharing-nothing parts (data parallelism). The point of Arc when compared to Rc is that the former has atomic (and thus thread-safe) reference counting, which means that, while there's a very slight performance loss due to the need to atomic operations, it gains Send and Sync implementations. The code below is a slight modification to it to try to mimic an application that does some processing and then streams the data to the connected peers. Mutex 意为互斥对象，用来保护共享数据。. Dec 26, 2020 · 4. lock(). [ −] pub struct MutexGuard<'a, T: ? Sized + 'a> { /* private fields */ } An RAII implementation of a “scoped lock” of a mutex. In the channel-case, I'd assume that both loops can run into the fast-path. Other Synchronization Primitives. Main difference for me now is that tokio's Sender does not implement Sink trait, which is something I miss. channel; const N: usize = 10; // Spawn a few threads to increment a shared variable (non Aug 10, 2022 · At the top of the sync module we find the words “Useful synchronization primitives”. This implies one can lock a tokio async mutex in one thread and unlock in another thread, which seems impossible using the std sync mutex Sep 15, 2023 · This tutorial provides an in-depth explanation and practical examples of Rust&#39;s concurrency primitives: Arc and Mutex. If you are sending messages between async and non-async code, then Tokio's documentation explains what you should do. The MutexGuard in the struct shouldn't be a reference, it should be just MutexGuard<'a, ()>, otherwise you're returning a reference to a local variable which just can't work. Rust aims to be a low-level language that still provides strong typed abstractions, making the developer’s life easier. Dec 17, 2016 · Rust mutexes do not work the way you are trying to use them. Aug 12, 2019 · rayon is the gold standard for OpenMP-like parallelism in Rust. Note: all senders (the original and its clones) need to be dropped for the receiver to stop blocking to receive messages with Receiver::recv. Apr 29, 2024 · MutexGuard. This sample code just Jan 21, 2022 · 2. Why does lock() return a Result? If the thread that held the Mutex panicked, the Mutex becomes “poisoned” to signal that the data it protected might be in an inconsistent state. This mutex will block threads waiting for the lock to become available. An async mutex. Data structures can be shared between threads if they're Send and Sync. use std::sync::{Arc, Mutex}; use std::thread; use std::sync::mpsc::channel; const N: usize = 10; // 共有変数を (非アトミックに) インクリメントするためにいくつかのスレッドを生成し、 // すべてのインクリメントが完了したら、メインスレッドに通知します。 Sep 9, 2023 · Sep 9, 2023. 3. bounded creates a channel of bounded capacity, i. I have a hunch that it's because for_each takes a closure of type F: Fn(T) + Sync while Apr 17, 2023 · The crossbeam channel is not async, and its send and recv methods will block instead. 例えば、以下のような場合はコンパイルエラーになります。 Jan 6, 2015 · Starting with Rust 1. Thread synchronization. It's fine to have an Arc<Mutex<Listener<String>>> though. Apr 25, 2020 · A Go channel provides typed data transfer between concurrent routines (goroutines). Now that Mutex::new is const, you can use global static Mutex locks without needing lazy initialization: Jul 16, 2022 · A mutex, or simply a lock, is a mechanism by which a single thread of a multi-threaded program can gain exclusive access to a resource. Note, however, that an RwLock may only be poisoned if a panic occurs while it is locked exclusively (write mode). Most usage of a mutex will simply unwrap() these results, propagating panics among threads to ensure that a possibly invalid invariant is not witnessed. Utilizing Rust high-performance compiler and powerful An async mutex is a mutex that is locked across calls to . A synchronous mutex will block the current thread when waiting to acquire the lock. Excellent for developers looking to master concurrent programming in Rust. Mutex provides mutual exclusion to shared memory between concurrent routines (goroutines). Looking at how my receiver and sender is defined I can see why this is incorrect because it has the following type: std::sync::mpsc::Receiver<std::string::String>. [ −] pub struct Sender<T> { /* private fields */ } The sending-half of Rust’s asynchronous channel type. Mutex. Channels are high level concept in Go which somewhere inside use Mutex only. source ·. A synchronous, bounded channel. Here are the benchmark results: Apr 29, 2024 · This mutex will block threads waiting for the lock to become available. oneshot. action(); Now the mutex is unlocked when guard is dropped, which is much more A common Go newbie mistake is to over-use channels and goroutines just because it’s possible, and/or because it’s fun. The multi-producer capability allows messages to be sent from many tasks. Apr 29, 2024 · This mutex will block threads waiting for the lock to become available. Mutexes in Rust. Tasks may not acquire the mutex in the order that they requested the lock, and it’s possible for a single task which repeatedly takes the lock to starve other tasks, which may be left waiting indefinitely. One question is: The std sync mutex (guard) is not Send, but the tokio async mutex (guard) is. However, the clone d variant only lives till the end of the statement: there is no binding to a. Hence the ownership model is an important part of Rust's Send thread safety, and may be the reason that Send is less intuitive than Sync when comparing with other languages. Nov 19, 2018 · Answer is NO. action(); This is better: let guard = mutex. 0 · source ·. Calling lock() on a poisoned mutex fails with A channel has the Sender and Receiver side. I removed this from my real application. If you make the following changes to your first example, it should work: Replace tokio::sync::Mutex with std::sync::Mutex so you don't have to use try_lock in the callback. lock() 或 . This reference stems from Arc . One thing is that the implementation can be very efficient, utilizing the knowledge that there will only be one message. The channel can also be closed manually by calling . Mar 14, 2022 · Conclusion. Two halves are returned, the first of which is a Sender handle, used to signal Oct 14, 2016 · I have some mutable state I need to share between threads. Looking It's because of Tokio's context-switching performance, like Golang, Tokio context-switch in the same thread to the next coroutine when the channel message is ready which is much cheaper than communicating between different threads, It's the same reason why async network applications usually perform better than sync implementations. However, the compiler is complaining about mismatched types on the receiving thread. §Examples This type acts similarly to std::sync::Mutex, with two major differences: lock is an async method so does not block, and the lock guard is designed to be held across . g. --. A Sender<T> is "thread safe" in that it can be sent between threads, but it cannot be shared between threads. The channel works for a spsc (single-producer, single-consumer) scheme. Dec 15, 2020 · For example, this is dangerous because you have to look at the signature of action() to figure out if the mutex unlocks immediately or not: let something = mutex. Understanding multithreading and the crucial role of channels in facilitating thread communication is essential for developing efficient, concurrent applications. You can create multiple receivers for a The mpsc channel is used to send commands to the task managing the redis connection. For example channels can help with constructing pipelines which will stop, when we close the channel. With these changes, the code compiles! Kanal utilizes a specially tuned mutex for its channel locking mechanism, made possible by the predictable internal lock time of the channel. The data can only be accessed through the RAII guards returned from lock and try_lock, which guarantees that the data The mutex code calls Lock twice in succession (from different goroutines). 5 milliseconds. Rust offers other synchronization primitives like RwLock and Condvar. // Channels have two endpoints: the `Sender<T>` and the `Receiver<T>`, Feb 16, 2024 · Conclusion. It ensures that only one thread can access the data at a time, which is known as maintaining “mutual exclusion”. 7. That said it's possible to use Rust standard mutex with the std-mutex feature and Kanal will perform better than competitors with that feature too. use std::sync:: mpsc; let ( tx, rx) = mpsc::channel(); 🚩. It is not able to prove certain guarantees when passing a reference to threads which might outlive the May 11, 2018 · If you have the same amount of read and write, Mutex<HashMap<K, Arc<Mutex<V>>>> would have the same effect while being a bit lighter in terms of memory. Utilizing Rust high-performance compiler and powerful May 14, 2024 · That being said, you probably wont want to use a mutex. I did some preliminary benchmarking and it seemed like the Mutex variant is quite faster than the channel one. The channel conceptually has an infinite buffer. In this module there are The transmission end of an unbounded mpsc channel. As a consequence, declaring a field Mutex<()> doesn't make sense, because it is protecting read-write access to the unit object that has no values to mutate. Fairness. Mutex if that fits your problem best. Also, in your sharding example, instead of spinning the threads, you could have a Vec<Mutex<HashMap<K, V>>> and like you said, use something like hash(key) % shards. I followed the concurrency section of the Rust book, which shares a vector between threads and mutates it. A Performance Comparison. The lock is a data structure that is part of the mutex that keeps track of who currently has exclusive Mutexes sequentialize access to a resource. :: channel. Think of Mutex as a way to say, "One at a time, please," ensuring that only one thread can access the data at any given moment. This module contains the tools we need to synchronize our multi-threaded program. The abstractions provided by channels help reduce the inherent complexities and pitfalls of multi Rust gives only guarantees about data races, but not about deadlocks and not about race conditions. mpsc stands for Multiple Producer, Single Consumer. In the callback, either use an unbounded channel, or make sure to release the lock before sending. async_mutex. The signature of lock (the most used method on a Mutex) is pub fn lock(&self) -> LockResult<MutexGuard<T>> which means you need a reference to the Mutex. unwrap(); let something = guard. ef in xb wo ex cd ju ec qp jl