APIC blues with SMP kernel

[Andre Costa]

Hi,

I have a P4 at work, and I have been having bad times trying to make it
work with hyper-threading enabled.

What happens are occasional lockups -- system appears to hang (keyboard,
mouse and X freeze, although machine still responds to pings; all other
services -- ssh, web, postgres -- are also dead).

Last time it froze, its last words were:

May 19 14:11:19 dali kernel: APIC error on CPU1: 00(40)
May 19 14:11:39 dali kernel: hda: dma_timer_expiry: dma status == 0x24

I know about APIC problems, but the fact is that if I pass 'noapic'
to the kernel before boot, the sibling CPU is detected but it doesn't
seem to be activated: it appears on top and gkrellm but it never does
anything (i.e. it remains with 0% usage).

I googled around, and this dma_timer_expiry problem seems to be kernel
2.6.x related. This leads me to think this is specific to Fedora kernel,
since RH backported many 2.6 features into its 2.4 kernel...

I am compiling a vanilla kernel as we speak, will try it out during the
weekend. However, given the fact that Fedora kernel is supposed to
provide superior performance compared to vanilla kernels, I would like
to use it instead, if at all possible...

So, my questions are:

1. any success stories out there about SMP + Fedora on P4s?
2. any black-magic to use besides 'noapic', 'acpi=ht' and 'apm=off'?
3. do vanilla kernels work with Fedora just fine (w/ or w/o SMP)?

BTW: FC2 is not an option in the near future, so please don't suggest I
upgrade ;)

TIA

Andre

-- 
Andre Oliveira da Costa