Messages in this thread | | | Date | Tue, 25 Feb 2014 18:53:09 -0800 | From | Andy Lutomirski <> | Subject | Re: [PATCH v4 5/6] timerfd: Add support for deferrable timers |
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On 02/20/2014 08:23 AM, Alexey Perevalov wrote: > From: Anton Vorontsov <anton@enomsg.org> > > This patch implements a userland-side API for generic deferrable timers, > per linux/timer.h: > > * A deferrable timer will work normally when the system is busy, but > * will not cause a CPU to come out of idle just to service it; instead, > * the timer will be serviced when the CPU eventually wakes up with a > * subsequent non-deferrable timer. > > These timers are crucial for power saving, i.e. periodic tasks that want > to work in background when the system is under use, but don't want to > cause wakeups themselves.
Please don't. This API sucks for all kinds of reasons:
- Why is it a new kind of clock? - How deferrable is deferrable? - It adds new core code, which serves no purpose (the problem is already solved).
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.
--Andy
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