Parallel Computing in Go

Transcript

1. Parallel Computation in Go Fabian Becker @geekproject
2. /me Open Source /me Piwik geekmonkey.org Ruby Evolutionary Algorithms Go
3. Why Go? • Why not? • C/C++ sucks • Distributed systems • Multicore hardware
4. What does it offer? • lightweight syntax • statically typed • garbage-collected (yay!) • concurrent • compiles to machine code
5. Anything else? • free and open source • enforced code style • duck typing (type inference) • static typing • fast
6. Example import ( “fmt” ”http” ) func handler(c *http.Conn, r *http.Request) { fmt.Fprintf(c, “Hello, %s\n”, r.URL.Path[1:]) } func main() { http.ListenAndServe(“:8080”, http.HandlerFunc(handler)) }
7. Concurrency • Communicating Sequential Processes – Hoare, 1978 • Goroutines – Lighter than Threads – 100.000s – Channels • “Don't communicate by sharing memory; share memory by communicating.”
8. Example #1 var a string func f() { a = “Hello World” } func main() { go f() println(a) }
9. Example #2 var c = make(chan int, 1) var a string func f() { a = "hello, world" c <­ 0 } func main() { go f() <­c print(a) }
10. Goroutines • Run on a set of threads • Ordinary functions (coroutines) – “go” keyword • Blocking – System calls block – Handled by the scheduler – Non-blocked routines moved to another thread • Memory efficient!
11. Channels • Typed • “<-” operator channel := make(chan string) • Worker function declaration: func worker(input string, results chan<­ string) { // do work results <­ result }
12. Channels #2 // A typed queue c := make(chan int) // Buffered vs. unbuffered unbuf := make(chan int) buf := make(chan int, 100) // Send to a channel c <­ 10 // Receive from a channel i := <­c
13. Testing • Go comes with a lightweight test suite – “go test” • Automated tests are great! func TestFoo(t *testing.T) { ... }
14. Benchmarking • Benchmark all the things! func BenchmarkHello(b *testing.B) { for i := 0; i < b.N; i++ { fmt.Sprintf("hello") } } • Nice for optimizing critical sections of your code
15. Who uses Go? • Google (No shit Sherlock!) • CloudFlare • Heroku • SoundCloud • Novartis • ...
16. Thanks for attending! Questions?
17. Resources • http://godashboard.appspot.com/ • https://gobyexample.com/ • http://golang.org • http://areyoufuckingcoding.me/topic/golang • http://geekmonkey.org/articles/20- comparison-of-ides-for-google-go