Re: [patch] voluntary-preempt-2.6.9-rc1-bk4-Q9

[Ingo Molnar]

* Thomas Charbonnel <thomas@xxxxxxxxxx> wrote:

> With ACPI compiled in and booting with acpi=off (which again doesn't
> seem to be honoured), here's another weird one :

> 00010000 0.003ms (+0.000ms): timer_interrupt (generic_handle_IRQ_event)
> 00010001 0.003ms (+2.878ms): mark_offset_tsc (timer_interrupt)
> 00010001 2.882ms (+0.000ms): do_timer (timer_interrupt)

do you have the NMI watchdog enabled? That could help us debugging this. 
Enabling the APIC/IO_APIC and using nmi_watchdog=1 would be the ideal
solution - if that doesnt work then nmi_watchdog=2 would be fine too,
but remove this code from arch/i386/kernel/nmi.c:

	if (nmi_watchdog == NMI_LOCAL_APIC)
		nmi_hz = 1;

(otherwise nmi_watchdog=2 would result in one NMI per second, not enough
to shed light on the above 2.8 msec latency.)

	Ingo
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