Le Wed, 27 Aug 2008 16:58:00 +0530 (IST), [EMAIL PROTECTED] a écrit : > 1. What is the difference between schedule() and > wait_event_interruptible_timeout execpt for the fact that > wait_event_interruptible_timeout will also respond to a timeout > period? Are both not meant to put to sleep the user process that call > them until they are woken up by the event( in case of > wait_event_interruptible_timeout) and the scheduler (in case of > scheduler) ?
schedule() simply gives the scheduler an opportunity to schedule another task. But the current task remains on the list of tasks ready for execution, so you will be woken later. Or even schedule() might not do anything if you are the only runnable task of the system, or if for some other reason the scheduler decides that you are the task that should be running on the CPU. The wait_event_*() family of functions changes the task state to TASK_INTERRUPTIBLE or TASK_UNINTERRUPTIBLE: the scheduler will not wake up until another task or interrupt explicitly wakes you up using wake_up(). For more details, read page 13 and following of http://lwn.net/images/pdf/LDD3/ch06.pdf. Sincerly, Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers and embedded Linux development, consulting, training and support. http://free-electrons.com -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to [EMAIL PROTECTED] Please read the FAQ at http://kernelnewbies.org/FAQ
