This sample program demonstrates how to create multiple goroutines and how the goroutine scheduler behaves with three logical processors.
The Go standard library has a function called GOMAXPROCS in the runtime package that allows us to specify the number of logical processors to be used by the scheduler.
Example
package main
import (
"fmt"
"runtime"
"sync"
)
func main() {
// Allocate three logical processors for the scheduler to use.
runtime.GOMAXPROCS(3)
// processTest is used to wait for the program to finish.
var processTest sync.WaitGroup
// Add a count of three, one for each goroutine.
processTest.Add(3)
// Declaration of three anonymous function and create a goroutine.
go func() {
defer processTest.Done()
for i := 0; i < 30; i++ {
for j := 51; j <= 100; j++ {
fmt.Printf(" %d", j)
if j == 100{
fmt.Println()
}
}
}
}()
go func() {
defer processTest.Done()
for j := 0; j < 10; j++ {
for char := 'A'; char < 'A'+26; char++ {
fmt.Printf("%c ", char)
if char == 'Z' {
fmt.Println()
}
}
}
}()
go func() {
defer processTest.Done()
for i := 0; i < 30; i++ {
for j := 0; j <= 50; j++ {
fmt.Printf(" %d", j)
if j == 50 {
fmt.Println()
}
}
}
}()
// Wait for the goroutines to finish.
processTest.Wait()
}