Messages in this thread | | | Date | Tue, 25 Oct 2005 16:28:48 +0200 | From | Ingo Molnar <> | Subject | Re: 2.6.14-rc5-rt6 -- False NMI lockup detects |
| |
* Steven Rostedt <rostedt@goodmis.org> wrote:
> Hi Ingo and Thomas, > > On some of my machines, I've been experiencing false NMI lockups. > This usually happens on slower machines, and taking a look into this, > it seems to be due to a short time where no processes are using > timers, and the ktimer interrupts aren't needed. So the APIC timer, > which now is used only for the ktimers, has a five second pause, and > causes the NMI to go off. The NMI uses the apic timer to determine > lockups.
this would be a bug - the jiffy tick should be processed every 1 msec, regardless of whether there are any ktimers pending. (in the future we want to use a special ktimer for the jiffy tick, but that's not implemented yet.)
> So, I added a more generic method. This only works for x86 for now, > but it has a #ifdef to keep other archs working until it implements > this as well. I added a nmi_irq_incr which is called by __do_IRQ in > the generic code. This is what is used in the NMI code to determine > if the CPU has locked up. This way we don't have to worry about what > resource we are using for timers.
this will be useful for tickless stuff - but right now 'no APIC timer irq for 5 seconds' is a 'must not happen'.
Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |