hello Vincenzo... > can anyone tell me if there's a relation between the sleep() C > function and the implementation of timers in Linux? > I know there's a relation between alarm() system call and timers, as > alarm() calls the kernel function settimer() that initializes > real_timer field of the calling process. Let's hope I understand you correctly. IMHO, yes, there is a correlation between sleep() and timer's implementation in kernel In general, kernel does below steps when a process wants to put itself in sleep (TASK_INTERRUPTIBLE) state: 1. Create dynamic timer (via init_timer). The interval is defined here 2. Inside the new declared timer, define a function to wake up the current process (process which wants to sleep) 3. Activate the timer and do schedule() 4. If the timer expired, timer's function calls wake_up_process with the saved process descriptor (the one who sets the timer). This means changing the process' stated back into TASK_RUNNING and reinsert it to back to run queue. need_resched field of current process is set to 1 to denote a need of rescheduling Does it answer your question? regards Mulyadi -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
