Messages in this thread |  | | | Subject | Re: A better interface, perhaps: a timed signal flag | | From | Steven Rostedt <> | | Date | Fri, 28 Jul 2006 12:44:49 -0400 |
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On Fri, 2006-07-28 at 17:41 +0100, Alan Cox wrote: > Ar Gwe, 2006-07-28 am 10:52 -0400, ysgrifennodd Theodore Tso: > > Good point, and limiting this facility to one such timeout per > > task_struct seems like a reasonable restriction. > > Why is this any better than using a thread or signal handler ? From the > implementation side its certainly horrible - we will be trying to write > user pages from an IRQ event. Far better to let the existing thread code > deal with it. >
If the user page is special, in that it is really a kernel page mapped to userspace. The implementation on making sure it doesn't disappear on the interrupt isn't that difficult.
But for real-time applications, the signal handling has a huge latency. Where as what Theodore wants to do is very light weight. ie. have a high prio task doing smaller tasks until a specific time that tells it to stop. Having a signal, would create the latency on having that task stop.
These little requests make sense really only in the real-time space. The normal uses can get by with signals. But I will say, the normal uses for computing these days are starting to want the real-time powers. :)
-- Steve
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