Re: Linux 2.6.21-rc1

Daniel Walker
2007-02-21T17:21:12Z

On Wed, 2007-02-21 at 18:07 +0100, Thomas Gleixner wrote:
> On Wed, 2007-02-21 at 08:24 -0800, Daniel Walker wrote:
> > > The most interesting core change may be the dyntick/nohz one, where timer
> > > ticks will only happen when needed. It's been brewing for a _loong_ time,
> > > but it's in the standard kernel now as an option.
> >
> > On i386 I get the following,
> >
> > TCP cubic registered
> > NET: Registered protocol family 1
> > NET: Registered protocol family 17
> > Testing NMI watchdog ... CPU#0: NMI appears to be stuck (24->24)!
> > CPU#1: NMI appears to be stuck (0->0)!
> > CPU#2: NMI appears to be stuck (0->0)!
> > CPU#3: NMI appears to be stuck (0->0)!
> >
> > when I add nmi_watchdog=1 to my boot args which worked on prior kernels.
> > On closer inspection it looks like arch/i386/kernel/io_apic.c :
> > check_timer() --> timer_irq_works() depends on IRQ0 incrementing jiffies
> > which is no longer the case AFAIK.
>
> At this point the PIT / HPET _is_ active and incrementing jiffies. The
> switch to local apic timers happens afterwards.

Could be the switch over then which confuses the NMI .

> > I'm not sure exactly how that relates to the NMI, but the check_timer()
> > function disabled the NMI through the io-apic if it can't get the
> > "timer" working through the io-apic.
>
> Boot log please.
>
> tglx
>

.config is in there too .

ftp://source.mvista.com/pub/dwalker/tglx/