Re: IRQ affinity vs. MTRRs, was Re: 36 bit MTRRs, Re: test10-pre1 problems on 4-way SuperServer8050

From: David Wragg (dpw@doc.ic.ac.uk)
Date: Thu Oct 12 2000 - 08:30:24 EST


Boszormenyi Zoltan <zboszor@externet.hu> writes:
> I came up with an idea. The MTRRs are per-cpu things.
> Ingo Molnar's IRQ affinity code helps binding certain
> IRQ sources to certain CPUs.

They are implemented as per-cpu things but the Intel manuals say that
all cpus should have the same MTRR settings. They also give
pseudo-code for how to update them on an SMP system, which mtrr.c
follows.

If the BIOS has set them up differently at boot time, mtrr.c will
complain and copy the MTRR settings of CPU0 to the others.

Regards,
David Wragg

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