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    SubjectRe: SMP processor rework help needed
    On 14 Oct 2001, Andi Kleen wrote:

    > In article <000b01c154ee$1d6a2610$6400a8c0@it0>,
    > "Tommy Faasen" <tommy@vuurwerk.nl> writes:
    > > Hi,
    > > I have this unique situation where cpu 1 has less features (like fxsr) then
    > > cpu 0.
    >
    > I used to have such an AMP machine too: a dual PII-300 with one Katmai and one
    > Deschutes. It's technically a violation of the specs; the Intel SMP spec
    > requires that the non boot cpus need to have a superset of the features
    > of the boot CPU. One CPU died, so it is symmetric now.
    >
    > For most capabilities it should already work in 2.4 after hpa's cpu
    > set rewrite, but FXSAVE is unfortunately a bit of a special case because
    > it is used in the scheduler context switch and that is required early
    > in the initialization for SMP bootup and changing it would be very
    > intrusive.
    >
    > In the 2.2 SuSE kernel it was fixed instead by adding a new kernel
    > command line option nofxsave that overrides the FXSAVE bit on the first
    > CPU. That is ok because such setup is very rare and is only generated by
    > people who build their own boxes; and these should also know how to pass
    > kernel command line arguments.

    This may sound like a dumb question but wouldn't simply swapping the CPUs
    have the same affect?

    Gerhard



    --
    Gerhard Mack

    gmack@innerfire.net

    <>< As a computer I find your faith in technology amusing.

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