Re: APIC error

mikpe@csd.uu.se
Thu, 15 May 2003 11:03:04 +0200


Rene Rebe writes:
> HI,
>
> On: Wed, 14 May 2003 14:55:37 +0200,
> mikpe@csd.uu.se wrote:
>
> > > Those errors only seem to happen during high disk-io (SCSI or IDE).
> > > What specific meaning do those errors have? Are they dangerous?
> >
> > They are defined in Intel's IA32 manual set, volume 3,
> > "System Programming Guide", downloadable from developer.intel.com.
> >
> > These errors mean that APIC bus messages are lost or have checksum errors.
> > You don't say which kernel you're using or which chipset, but chances are
> > your mobo's APIC bus is noisy.
> >
> > > Each CPU survives hours in memtest86 ... And with maxcpus=1 it also
> > > does not seem to happen ... The BIOS is latest.
> >
> > You can try booting with "noapic", that should let you keep using SMP
> > while avoiding your possibly buggy APIC bus.
>
> Thanks for the anwer I googled for this before the mail but only found
> much noise ... I'll triy noapic (I thought this would disable SMP,
> too), but I already had to notice that with maxcpus=1 I also get some
> few APIC errors.
>
> Is there drawback in using noapic in SMP mode?

No load balancing of I/O interrupts since they will all be directed to
CPU 0 only. Unless your dual P5 is servicing a lot of interrupts, I doubt
it will make a noticeable difference.
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