Let’s talk about how to use golang scheduling

The Golang scheduler is an important part of the Golang language, which can effectively manage Goroutines in the Golang program. In Golang, Goroutines are lightweight threads that can perform multiple tasks at the same time, effectively improving the simultaneous execution efficiency of the program. This article will introduce the basic usage of Golang scheduler.

1. Scheduler Overview

The Golang scheduler is a component in the Golang runtime system, which is responsible for managing all Goroutines in the Golang program. Goroutines are the basic unit of concurrent execution in the Golang language. When a Goroutine is started in a program, it puts the task into the task queue, and the Golang scheduler decides when to execute the task. The Golang scheduler is responsible for placing tasks into the Goroutine queue, coordinating and executing tasks.

2. Implementation

Golang scheduler is implemented by the Golang compiler and runtime system together. The Golang compiler compiles Golang code into machine code and inserts specific assembly code. The runtime system is responsible for executing compiled code, including managing Goroutines, stacks, coroutine blocking and other related issues.

3. Scheduler parameters

The Golang scheduler mainly has two parameters: P and G. P stands for processor, indicating the number of CPU cores on which Goroutines execute. G represents the number of Goroutines, indicating the number of tasks that can be run simultaneously in the Golang program. By adjusting these two parameters, the execution efficiency of the Golang program can be changed.

4. Golang scheduler scheduling strategy

In the Golang scheduler, tasks will be arranged in the P and G queues. When a Goroutine completes its task, it is immediately removed from the G queue. However, the Golang scheduler will not immediately remove the Goroutine from P. There may be Goroutines from other tasks in P.

The scheduling strategy used by the Golang scheduler is a priority-based preemptive scheduling algorithm. The biggest advantage of this algorithm is that it can prevent a certain Goroutine from occupying the CPU for a long time, causing other Goroutines to be unable to execute. The scheduler will select an appropriate P based on the Goroutine's priority and put the Goroutine into the execution queue of the P.

5. Scheduler usage

In Golang, we can use the go() function to start a Goroutine. The Golang scheduler will put the Goroutine into the default P for execution by default. If you want to control the execution efficiency of the program more precisely, you can use the runtime.GOMAXPROCS() function to adjust the number of P.

In addition, Golang also provides some functions for controlling the scheduler, such as the runtime.Gosched() function and the runtime.LockOSThread() function wait. runtime.Gosched()The function can actively give up the P used by the current Goroutine and put it in the waiting queue so that other Goroutines have the opportunity to execute. runtime.LockOSThread()The function can lock the current Goroutine to a specific OS thread to ensure that it can occupy the thread for a long time.

6. Summary

The Golang scheduler is a very important part of the Golang language, which can effectively improve the execution efficiency of the program. It is very important to understand the implementation principles, parameters, scheduling strategies, etc. of the Golang scheduler. Only by mastering how to use the scheduler can you write Golang programs more efficiently.

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