What is the implementation principle of golang lock?

The implementation principle of golang lock is to protect access to shared resources through mutual exclusion locks and read-write locks. Mutex is a basic locking mechanism used to protect shared resources. It uses a flag to indicate whether the resource is occupied. When a goroutine acquires the mutex, other goroutines will be blocked until the goroutine releases the lock. until. Read-write lock is a lock mechanism used in scenarios where there is more reading and less writing. It allows multiple goroutines to read shared resources at the same time, and only allows one goroutine to write operations.

# Operating system for this tutorial: Windows 10 system, Dell G3 computer.

In the Go language, the implementation principle of locks is mainly based on mutual exclusion locks (Mutex) and read-write locks (RWMutex).

Mutex (Mutex):

Mutex is a basic locking mechanism used to protect shared resources. It uses a flag bit to indicate whether the resource is occupied. When a goroutine acquires the mutex lock, other goroutines will be blocked until the goroutine releases the lock.

The implementation principle of mutex lock mainly involves the following two key points:

• Hardware instructions: The bottom layer of Go language uses some low-level atomic instructions, such as CAS (Compare -and-Swap) to implement the operation of mutex lock. These instructions can ensure that access to shared resources is atomic when multiple goroutines are executed concurrently.

• System call: In Linux systems, when a goroutine cannot obtain the mutex lock, it will enter a sleep state and add itself to the waiting queue. When the lock is released, the goroutine in the waiting queue will be awakened and compete for the lock resource.

The implementation of mutex locks may differ on different operating systems, but the basic principles are similar.

Read-write lock (RWMutex):

Read-write lock is a lock mechanism used in scenarios where there is more reading and less writing. It allows multiple goroutines to read shared resources simultaneously, but only allows one goroutine to write.

The implementation principle of RWMutex is mainly based on mutex locks and condition variables. When there is a write operation, RWMutex will block other read and write operations until the write operation is completed. When there is a read operation, RWMutex will allow other read operations to continue, but will block the write operation.

RWMutex maintains two counters in implementation: read counter and write counter. The read counter records the number of goroutines currently performing read operations, and the write counter records the number of goroutines currently performing write operations.

The implementation principle of read-write locks can ensure higher concurrency performance and throughput in scenarios where there is more reading and less writing.

The lock mechanism of Go language mainly protects access to shared resources through mutual exclusion locks and read-write locks. Mutex locks use low-level atomic operations and system calls to achieve mutually exclusive access to shared resources. The read-write lock allows multiple goroutines to read shared resources at the same time, but only allows one goroutine to perform write operations. The implementation principles of these lock mechanisms ensure safe access to shared resources in a concurrent environment.

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