* nmi_watchdog default setting on i386 and x86_64
@ 2006-05-22 23:48 Mike Mason
2006-05-23 14:15 ` Mikael Pettersson
0 siblings, 1 reply; 3+ messages in thread
From: Mike Mason @ 2006-05-22 23:48 UTC (permalink / raw)
To: linux-kernel
Does anybody know the reasoning behind having nmi_watchdog turned off by
default on i386 and on by default on x86_64. I've heard that i386 had
problems with false positives in the past, but that local apic watchdog
may make that concern obsolete.
Regards,
Mike Mason
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: nmi_watchdog default setting on i386 and x86_64
2006-05-22 23:48 nmi_watchdog default setting on i386 and x86_64 Mike Mason
@ 2006-05-23 14:15 ` Mikael Pettersson
2006-05-23 14:37 ` Andi Kleen
0 siblings, 1 reply; 3+ messages in thread
From: Mikael Pettersson @ 2006-05-23 14:15 UTC (permalink / raw)
To: Mike Mason; +Cc: linux-kernel
Mike Mason writes:
> Does anybody know the reasoning behind having nmi_watchdog turned off by
> default on i386 and on by default on x86_64. I've heard that i386 had
> problems with false positives in the past, but that local apic watchdog
> may make that concern obsolete.
On i386 the problems are mainly hardware and BIOS. In particular,
lots of Dell laptops have capable hardware but broken BIOSen that
hang the machines if we try to enable anything sending performance
counter interrupts via the local APIC.
/Mikael
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: nmi_watchdog default setting on i386 and x86_64
2006-05-23 14:15 ` Mikael Pettersson
@ 2006-05-23 14:37 ` Andi Kleen
0 siblings, 0 replies; 3+ messages in thread
From: Andi Kleen @ 2006-05-23 14:37 UTC (permalink / raw)
To: Mikael Pettersson; +Cc: linux-kernel, mmlnx
Mikael Pettersson <mikpe@csd.uu.se> writes:
> Mike Mason writes:
> > Does anybody know the reasoning behind having nmi_watchdog turned off by
> > default on i386 and on by default on x86_64. I've heard that i386 had
> > problems with false positives in the past, but that local apic watchdog
> > may make that concern obsolete.
>
> On i386 the problems are mainly hardware and BIOS. In particular,
> lots of Dell laptops have capable hardware but broken BIOSen that
> hang the machines if we try to enable anything sending performance
> counter interrupts via the local APIC.
AFAIK that trouble was mostly when you forced the local APIC on against
the wishes of the BIOS. That was always a dumb idea and gladly
Linux doesn't try that by default anymore.
-Andi
^ permalink raw reply [flat|nested] 3+ messages in thread
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2006-05-22 23:48 nmi_watchdog default setting on i386 and x86_64 Mike Mason
2006-05-23 14:15 ` Mikael Pettersson
2006-05-23 14:37 ` Andi Kleen
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