How to reduce gc in golang

Golang is a programming language launched by Google. Its advantages lie in efficient concurrency performance, minimalist syntax and powerful garbage collection mechanism. Garbage collection is an important feature of Golang. It allows programmers not to worry about memory recycling and can focus on the implementation of business logic. However, garbage collection also brings some problems, the biggest of which is the performance problem caused by GC. So, how to effectively reduce GC overhead? The following will be discussed based on actual cases.

1. Use value types whenever possible

In Golang, variables can be divided into value types and reference types. Value types include int, float, bool, etc., and reference types include arrays, slices, maps, etc. Unlike other languages, value types in Golang are passed by copying during the transfer process. This means that if a variable of value type is passed to a function, the function will receive a copy of the variable. Reference types pass a reference to the underlying data. This can easily cause memory escapes and frequent GC.

Therefore, use value types instead of reference types whenever possible. For example, use arrays instead of slices, and use plain structs instead of maps. This can reduce the frequency of memory allocation and garbage collection.

2. Avoid using global variables

Global variables are one of the most frequently used variables in a program. However, the use of global variables will increase the burden on the GC. The reason is that the life cycle of global variables is as long as the program. Even some variables in the program that are no longer used will always occupy memory space, causing garbage collection to be unable to recycle these no longer used variables, thereby reducing program performance.

Therefore, we should avoid using global variables as much as possible. If you must use global variables, you should reduce their number and life cycle as much as possible, which can reduce the burden on the GC.

3. Using sync.Pool

sync.Pool is a pool provided in the Golang standard library for storing temporary objects. When the program is running, if a large number of objects or memory blocks need to be created, using sync.Pool can reduce the number of memory allocations and reduce the pressure of garbage collection.

For example, when processing http requests, each request needs to create a ResponseWriter and Request object. If you use sync.Pool to create these objects, you can reduce the number of memory allocations, thereby reducing the burden on the GC.

4. Use sync.Map in the standard library

In Golang, map is an efficient data structure that can be used to store key-value pairs. However, you need to be very careful when using maps, especially in high-concurrency environments. Because map is not thread-safe, locking is required to ensure concurrency safety, which will increase the burden on the GC.

Therefore, we can use sync.Map provided in the standard library. This data structure is thread-safe and can avoid excessive lock granularity or unnecessary locking operations, thereby reducing GC pressure.

5. Note the impact of GC

In Golang, the garbage collector is automatically triggered, but the work of the garbage collector will block all user threads. Therefore, if there are a large number of memory allocations while the garbage collector is running, it will take longer for the garbage collector to clean up the garbage. This causes the user thread to be blocked for longer, which in turn affects program performance.

Therefore, we need to pay special attention to the impact of the garbage collector and avoid large memory allocations during the operation of the garbage collector.

Summary:

Golang’s garbage collection mechanism is a major advantage, allowing programmers to focus on the implementation of business logic. However, garbage collection also brings some problems, the biggest of which is the performance problem caused by GC. This article summarizes several methods to reduce GC overhead, such as using value types, avoiding global variables, using sync.Pool, using sync.Map in the standard library and paying attention to the impact of GC. These techniques can help us make better use of the garbage collection mechanism when writing Golang programs, reduce the GC overhead of the program, and thereby improve the performance of the program.

The above is the detailed content of How to reduce gc in golang. For more information, please follow other related articles on the PHP Chinese website!