Re: [patch] enabling APIC and NMI watchdog on UP systems

From: Ingo Molnar (
Date: Thu Sep 28 2000 - 18:13:06 EST

On Fri, 29 Sep 2000, Keith Owens wrote:

> Using performance counter 1 for NMI conflicts with using the
> performance counters for tuning. IMHO it is better to default to NMI
> off for UP so we do not disturb people who are doing performance
> monitoring. [...]

the number of people experiencing hard lockups, and the importance of
debugging these (annoying) lockups IMO far outweighs the potential
inconvenience caused by having to disable the NMI oopser for performance

> That then requires a mechanism for configuring the UP NMI and
> activating it on the fly, which complicates the code.


> set_nmi_counter_local() has to be called after every NMI to reset the

oops - i *am* reprogramming the counter (i obviously tested wether the NMI
oopser works on a non-SMP P6 system, and checked the NMI counter in
/proc/interrupts), but it was left out of the patch by accident [forgot to
create a .orig file]. I've attached the -C3 patch.


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