On Sun, 2007-03-11 at 16:13 -0700, Davide Libenzi wrote: > On Sun, 11 Mar 2007, Davide Libenzi wrote: > > > This patch introduces a new system call for timers events delivered > > though file descriptors. This allows timer event to be used with > > standard POSIX poll(2), select(2) and read(2). As a consequence of > > supporting the Linux f_op->poll subsystem, they can be used with > > epoll(2) too. > > The system call is defined as: > > > > int timerfd(int ufd, int clockid, int tmrtype, const struct timespec *utmr); > > > > The "ufd" parameter allows for re-use (re-programming) of an existing > > timerfd w/out going through the close/open cycle (same as signalfd). > > If "ufd" is -1, s new file descriptor will be created, otherwise the > > existing "ufd" will be re-programmed. > > The "clockid" parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME. > > The "tmrtype" parameter allows to specify the timer type. The following > > values are supported: > > > > TFD_TIMER_REL > > The time specified in the "utmr" parameter is a relative time > > from NOW. > > > > TFD_TIMER_ABS > > The timer specified in the "utmr" parameter is an absolute time. > > > > TFD_TIMER_SEQ > > The time specified in the "utmr" parameter is an interval at > > which a continuous clock rate will be generated. > > > > Duh! Forgot to update the documenation. Now timerfd() gets an itimerspec. > For TFD_TIMER_REL only the it_interval is valid, and it's the relative > time. For TFD_TIMER_ABS, only the it_value is valid, and that the expiry > absolute time. For TFD_TIMER_SEQ, it_value tells when the first tick > should be generated, and it_interval tells the period of the following > ticks. >
You should probably make it behave like the other things that use itimerspec, just to avoid confusion -- i.e. timers are relative by default, there's a flag that makes them absolute, they expire when it_value specifies, and repeat every it_interval nanoseconds if it_interval is non-zero. i.e. int timerfd(int ufd, int clockid, int flags, const struct timespec *utmr); with TFD_TIMER_ABS in flags making the timer absolute instead of relative (and no TFD_TIMER_REL or TFD_TIMER_SEQ at all). -- Nicholas Miell <[EMAIL PROTECTED]> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
