C Coroutine

Transcript

1. C Coroutine Multiple tasks with single CPU
2. Outline 1. Process, Thread, Event 2. Coroutine 3. C Couroutline Library 4. Protothread 5. Reference
3. Process, Thread, Event • Process & Thread ◦ Resource cost ◦ Resource lock ◦ process1/thread1(io1,do1), process2/thread2(io2, do2) • Event ◦ Lots of nested callbacks ◦ set(io1,do1); set(io2,do2); loop_event();
4. Coroutine foo() { static int i; for(i = 0; i < 10; i++){ printf(“%d\n”, i); yield i; } } foo(); // 0 foo(); // 1
5. Coroutine a() { a_init(); while(!io1()) yield; do1(); } b() { b_init(); while(!io2()) yield; do2(); } loop{a(); b();};
6. C Coroutine Library • Protothread ◦ switch case • State threads ◦ longjmp + setjmp • couroutine ◦ ucontext
7. Protothread int function(void) { static int i, state; switch (state) { case 0: /* start of function */ for (i = 0; i < 10; i++) { state = __LINE__ + 2; /* so we will come back to "case __LINE__" */ return i; case __LINE__:; /* resume control straight after the return */ } } }
8. Protothread
9. Reference • http://programmers.stackexchange. com/questions/147182/ • http://coolshell.cn/articles/10975.html • http://coolshell.cn/articles/12012.html