Re: [PATCH] NMI watchdog documentation

From: Mikael Pettersson (mikpe@csd.uu.se)
Date: Wed Jul 30 2003 - 17:53:00 EST


On Wed, 30 Jul 2003 22:40:52 +0300, Ville Herva wrote:
>Ok, you got me confused (thankfully I didn't submit anything for inclusion
>yet. :)
...
>So... Should it be something like:
>
>+For x86-64, the needed APIC is always compiled in, and the NMI watchdog is
>+always enabled with perctr mode. Currently, mode=2 (local APIC) does not

always enabled with I/O-APIC mode.

>+work on x86-64. IO APIC mode (mode=1) is the default. Using NMI watchdog

Using local APIC

>+(mode=1) needs the first performance register, so you can't use it for

(mode=2)

>+other purposes (such as high precision performance profiling.)

>(Is the last sentence only valid for x86-64?)

No, it's true for both x86 and x86-64. However, both oprofile
and the perfctr driver disable the local APIC NMI watchdog, so
the statement is only true for other drivers that don't do this.

/Mikael
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