Re: UP local APIC is deadly on SMP Athlon

[Willy Tarreau <willy@w.ods.org>]

Hi !

Good catch, Ion !

On Sat, Feb 22, 2003 at 03:05:37AM -0500, Ion Badulescu wrote:
> As a matter of fact, I got very interesting numbers from that printk() I
> added:
> 
> - all the Intel and single proc AMD printed "0".
> - all the dual AMD machines printed "1".

Same here, dual AMD/760MPX.

BTW, there's something I don't understand. The only reference to
APIC_init_uniprocessor() I found was in smpboot.c:1044. It's called when the
SMP config has not been found at boot time (and it also sets
phys_cpu_present_map to 1, BTW). My problem is that this function is executed
on my dual-k7, on an SMP kernel (because I see the added message), but I
don't see the "SMP motherboard not detected" message which should be displayed
just before APIC_init_uniprocessor().

So I suspect there's something strange in this code that might explain why
only CPU0 receives the interrupts, but I don't understand the code path !

I'd appreciate it if someone has a clue... I can provide .config and dmesg
if needed. By this time, I'll add printk's everywhere in the kernel.

Cheers,
Willy