Pointers or Values in Go Structs: What's the Performance Impact?

Pointers vs. Values in Go Structs: Performance Implications

In Go, structs provide a way to aggregate data of different types into a single composite value. When defining a struct, one can opt to use either a pointer or a value to hold another field. This choice can impact the performance of the program.

Performance Implications

Numeric primitive types, such as int, are more efficient to copy than to dereference a pointer. Complex data structures may also be faster to copy if they are smaller than a cache line (usually around 128 bytes).

However, for larger data structures, performance is more dependent on the specific details of the program and the hardware being used. It is advisable to benchmark the code to identify any potential bottlenecks.

When to Use Pointers

Choosing between pointers and values should be primarily based on the program's logic rather than performance considerations. However, here are some guidelines to help you decide:

• Use a pointer when passing an argument that needs to be modified.
• Use a pointer when checking for unset or nil values.
• Use a pointer when accessing methods attached to pointer receivers.

Example

Consider the following struct:

type Exp struct {
  foo int
  bar *int
}

If you need to create a linked list of elements using this struct, pointers are essential to traverse and modify the list. However, if you have a set of simple values that will not be changed, using values can be more efficient.

Conclusion

Ultimately, the choice between pointers and values in Go structs depends on the specific needs of the program. By understanding the performance implications and considering the underlying logic, developers can make informed decisions to optimize their code.

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