Created
October 11, 2011 04:30
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Testing scaling of parallelism in Go
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| package main | |
| import ( | |
| "fmt" | |
| "time" | |
| "flag" | |
| "runtime" | |
| ) | |
| // basic fibonacci routine | |
| func fib(n int) int { | |
| if n <= 1 { | |
| return n | |
| } | |
| return fib(n - 1) + fib(n - 2) | |
| } | |
| func fib_goroutine(n int, ch chan int) { | |
| ch <- fib(n) | |
| } | |
| func main() { | |
| n := flag.Int("n", 30, "The number to pass to the fib function") | |
| c := flag.Int("c", 500, "The number of times to repeat the function") | |
| p := flag.Int("p", 2, "The max number of CPU processors to use") | |
| flag.Parse() | |
| i := 0 | |
| ch := make(chan int) | |
| // set maximum processor cores to use (see http://golang.org/doc/effective_go.html#parallel) | |
| runtime.GOMAXPROCS(*p) | |
| // run test | |
| start := time.Nanoseconds() | |
| for i = 0; i < *c; i++ { | |
| go fib_goroutine(*n, ch) | |
| } | |
| for i = 0; i < *c; i++ { | |
| <- ch | |
| } | |
| stop := time.Nanoseconds() | |
| // print result | |
| time_ := (stop - start) / 1e6 | |
| fmt.Printf("time = %dms", time_) | |
| } |
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