Re: QUESTION: Network hangs with BP6 and 2.4.x kernels, hardware

Ingo Molnar
2001-01-12T18:17:21Z

On Fri, 12 Jan 2001, Manfred Spraul wrote:

> The PPro local apic documentation says:
> <<<<<<<
> The processor's local APIC includes an in-service entry and a holding
> entry for each priority level. To avoid losing interrupts, software
> should allocate no more than 2 interrupt vectors per priority.
> >>>>>>>>
>
> Ok, we must reorder the vector numbers for our own interrupts
> (0xfb-0xff), but that doesn't explain our problems: we don't loose
> reschedule interrupts, we have problems with normal interrupts - and
> there we only use 2 irq at the same priority level.

we *already* reorder vector numbers and spread them out as much as
possible. We do this in 2.2 as well. We did this almost from day 1 of
IO-APIC support. If any manually allocated IRQ vector creates a '3 vectors
in the same 16-vector region' situation then thats a bug in hw_irq.h..

the 'loss of interrupts' above does not include external interrupts, only
local interrupts (such as the APIC timer interrupt) can get lost in such a
situation.

(nevertheless there is something going on.)

Ingo