Re: APIC support on Slot-A Athlon, K6

[Mikael Pettersson]

On Mon, 8 Dec 2003 05:58:59 -0600, Ryan Underwood wrote:
>> Furthermore, I/O-APIC usage requires (in hardware) that the
>> processor has a local APIC.
>
>What can the APIC support alone accomplish, without an I/O-APIC?
>Just NMI watchdog and related things? (looking at CONFIG_APIC help)
>Looks like I/O-APIC is the real desired feature, but a functioning local
>APIC, though not very useful by itself, is a prerequisite for it.

Local APIC gives you:
- using the local APIC timer instead of the mobo's legacy timer
- thermal management interrupts on P4s (dunno about K7s/K8s)
- performance counter interrupts, which can be used as an NMI
  source (watchdog, profiling) or for performance analysis

I/O-APIC gives you:
- more interrupt vectors ==> less IRQ sharing ==> improved
  stability and performance
- lower-overhead interrupt management
- I/O-APIC NMI watchdog (another timer with NMI delivery mode)
-
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