How to set the number of coroutines in Golang

Number of Golang coroutines: How to avoid too many?

Golang launches a coroutine concurrency model, allowing developers to easily create hundreds or thousands of coroutines, making multi-threaded programming extremely easy. However, as the number of coroutines increases, it also brings some problems, such as memory usage, CPU consumption, etc. This article will discuss how to set the number of coroutines in Golang and how to avoid too many coroutines.

Default value for number of coroutines in Golang

Golang allows hundreds or thousands of coroutines to be created at one time, but keep in mind that the number of these coroutines depends on the underlying limitations of the system. The default limit on the number of coroutines in macOS and Linux systems is 1024, while the default number in Windows reaches 2048.

During execution, these values ​​may be affected by other factors, such as user and system resource usage.

Set the number of coroutines in Golang

In order to set the number of coroutines in Golang, you can modify the value of the GOMAXPROCS environment variable. The default value of GOMAXPROCS is the number of available CPUs of the machine, which can be viewed through the following code:

fmt.Println(runtime.NumCPU())

If you want to limit the number of coroutines, it is best to set the value of GOMAXPROCS in the code instead of relying on the default value. For example:

runtime.GOMAXPROCS(4)

This will limit the number of coroutines to 4, making the code more efficient.

Avoid too many coroutines

Too many coroutines may lead to problems such as excessive memory usage and excessive CPU consumption. In order to prevent these problems, the following preventive measures can be taken:

1. Limit the number of coroutines: When writing code, you can limit the number of coroutines based on different task requirements. For example, in the case of heavy calculations, a smaller number of coroutines can be set, making the program more efficient.
2. Optimize code: When writing code, avoid using too many coroutines as much as possible. Multiple tasks can be combined into one coroutine to reduce the number of coroutines.
3. Thread pool: Limit the number of coroutines and reduce memory consumption by using a pool. You can use Golang's goroutine pool library to implement the coroutine pool.

Conclusion

Golang’s coroutine concurrency model makes multi-thread programming relatively easy, but you need to pay attention to some problems caused by too many coroutines. To avoid these problems, the number of coroutines should be set in the code and the code should be optimized to reduce the number of coroutines as much as possible. At the same time, using the coroutine pool can also reduce memory consumption. Through the above measures, Golang's coroutine model can be used more effectively to improve the efficiency and performance of the program.

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