Re: x86's nmi_hz wrt. oprofile's nmi_timer_int.c

[Andi Kleen]

> Again, the code in nmi_timer_int.c doesn't.
> 
> It uses the NMI watchdog timer interrupts, it catches DIE_NMI
> events.
> 
> > Does that answer your question?
> 
> Not really.

Ah see what you mean now. The nmi_timer_int code can only
be active ever when the cpu is not known to nmi_int.c and 
when the nmi watchdog is in io apic mode. But IO apic mode
doesn't use the fast check/slowdown because it always runs
at HZ frequency. That only happens in LAPIC mode.

The standard fallback mode for unknown CPU is the non NMI timer 
fallback in oprofile_init, the IO APIC mode happens near never in practice.

-Andi

-- 
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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