How many goroutines can be created simultaneously?

In Go, the number of goroutines that can be created simultaneously is mainly limited by system resources (memory and CPU time), not by the language itself. Theoretically, hundreds of thousands or even millions of goroutines can be created, as they are very lightweight compared to OS threads.

Goroutines occupy a small stack (starting at about 2 KB and can grow dynamically), so memory limitation is the main factor.

Example of creating a large number of goroutines:

package main

import (
    "fmt"
    "sync"
)

func main() {
    var wg sync.WaitGroup
    const num = 100000
    wg.Add(num)

    for i := 0; i < num; i++ {
        go func(n int) {
            defer wg.Done()
            // some work
            if n%20000 == 0 {
                fmt.Println("Goroutine", n)
            }
        }(i)
    }

    wg.Wait()
    fmt.Println("All goroutines are finished")
}

However, keep in mind that too many goroutines can lead to increased scheduling time and memory consumption, so it is necessary to balance the number of goroutines with available resources.