Messages in this thread | | | Subject | Re: NO_HZ: timer interrupt stuck | From | Thomas Gleixner <> | Date | Thu, 22 Feb 2007 18:39:19 +0100 |
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On Thu, 2007-02-22 at 09:26 -0800, David Miller wrote: > BTW, I'm adding support for sparc64, and before I get much further > will the code handle a oneshot-only device? That's basically what I > have (sparc64 basically has a TSC and a "comparison" register, you > write the "comparison" register with the TSC value at which you'd like > the timer interrupt to occur, so it's one-shot and you have to write > it again to get the next timer).
Yes, all you need is to omit the CLOCK_EVT_FEAT_PERIODIC flag when you register your device.
> I see logic in the generic code to do periodic events when the > timer only provides one-shot ticks. But as far as I can tell > both the HPET and the local APIC support periodic timers so > I can't tell how much testing that code has gotten :-)
Not much :)
> I, in fact, don't see any clockevent device in the current tree that > does not set CLOCK_EVT_FEAT_PERIODIC.
There is an ARM patch which makes use of it.
> I guess you could clear that bit just to test those generic code > paths. :-)
yep.
> BTW, sparc64 always did the trick where the do_timer() work was done > by one of the per-cpu local timer interrupts, I'm glad the idea gained > traction generically. :-)))
:)
tglx
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