Messages in this thread | | | From | Andy Lutomirski <> | Date | Tue, 4 Mar 2014 14:43:35 -0800 | Subject | Re: [PATCH v4 5/6] timerfd: Add support for deferrable timers |
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On Tue, Mar 4, 2014 at 2:11 PM, Thomas Gleixner <tglx@linutronix.de> wrote: > On Tue, 4 Mar 2014, Andy Lutomirski wrote: > >> On Tue, Mar 4, 2014 at 12:58 PM, Thomas Gleixner <tglx@linutronix.de> wrote: >> > On Tue, 25 Feb 2014, Andy Lutomirski wrote: >> >> On the other hand, if you added a fancier version of timerfd_settime >> >> that could explicitly set the slack value (or, equivalently, the >> >> earliest and latest allowable times), that could be quite useful. >> >> >> >> It's often bugged me that timer slack is per-process. >> > >> > That's a totally different issue. There is a world aside of timerfd >> > timers. >> >> This is a patch to add deferrable support *to timerfd*. I'm asking > > There is a new patch series which adds deferrable support to all timer > related interfaces which have a flags field. And that's the only > sensible solution right now. > > We do no add another random special case syscall for timerfd just > because timerfd is linux specific.
What syscalls? I can think of exactly two timer interfaces that actually accept a clock id and flags: clock_nanosleep and timerfd_settime.
> > No, we want to support that stuff right now with the existing > interfaces as we have to revisit all of the timer related interfaces > in the near future anyway due to the Y2038 issue. > > And your idea of per thread slack is completely bogus. If we want to > make the slack value usefull then it needs to be done per timer and > not per thread/process.
This is *exactly* what I'm suggesting.
> > But we cannot do that right now as we cannot whip up severl dozen of > new syscalls just because we want to add slack/deferrable whatever > properties.
Two syscalls, right?
> > Once we agree on a solution to the Y2038 issue on 32bit with a unified > 32/64 bit syscall interface which simply gets rid of the timespec/val > nonsense and takes a simple u64 nsec value we can add the slack > property to that without any further inconvenience. > > Thanks, > > tglx >
-- Andy Lutomirski AMA Capital Management, LLC
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