goroutine

How many goroutines can I use painless? For example wikipedia says, in Erlang 20 million processes can be created without degrading performance. Update: I've just investigated in goroutines performance a little and got such a results: It looks like goroutine lifetime is more then calculating sqrt() 1000 times ( ~45µs for me ), the only limitation is memory Goroutine costs 4 — 4.5 KB If a goroutine is blocked, there is no cost involved other than: memory usage slower garbage-collection The costs (in terms of memory and average time to actually start executing a goroutine) are: Go 1.6.2 (April

This code selects all xml files in the same folder, as the invoked executable and asynchronously applies processing to each result in the callback method (in the example below, just the name of the file is printed out). How do I avoid using the sleep method to keep the main method from exiting? I have problems wrapping my head around channels (I assume that's what it takes, to synchronize the results) so any help is appreciated! package main import ( "fmt" "io/ioutil" "path" "path/filepath" "os" "runtime" "time" ) func eachFile(extension string, callback func(file string)) { exeDir := filepath

Is this example usage of sync.WaitGroup correct? It gives the expected result, but I am unsure about the wg.Add(4) and the position of wg.Done() . Does it make sense to add the four goroutines at once with wg.Add() ? http://play.golang.org/p/ecvYHiie0P package main import ( "fmt" "sync" "time" ) func dosomething(millisecs time.Duration, wg *sync.WaitGroup) { duration := millisecs * time.Millisecond time.Sleep(duration) fmt.Println("Function in background, duration:", duration) wg.Done() } func main() { var wg sync.WaitGroup wg.Add(4) go dosomething(200, &wg) go dosomething(400, &wg) go

Below is a struct of type Stuff. It has three ints. A Number , its Double and its Power . Let's pretend that calculating the double and power of a given list of ints is an expensive computation. type Stuff struct { Number int Double int Power int } func main() { nums := []int{2, 3, 4} // given numbers stuff := []Stuff{} // struct of stuff with transformed ints double := make(chan int) power := make(chan int) for _, i := range nums { go doubleNumber(i, double) go powerNumber(i, power) } // How do I get the values back in the right order? fmt.Println(stuff) } func doubleNumber(i int, c chan int)