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    SubjectRe: [PATCH] cputopology: Always define CPU topology information [4th try]
    Nathan Lynch wrote:
    > Hi Ben-
    > Ben Hutchings wrote:
    > > Not all architectures and configurations define CPU topology information.
    > > This can result in an empty topology directory in sysfs, and requires
    > > in-kernel users to protect all uses with #ifdef - see
    > > <>.
    > >
    > > The documentation of CPU topology specifies what the defaults should be
    > > if only partial information is available from the hardware. So we can
    > > provide these defaults as a fallback.
    > I've been looking at adding topology information to powerpc and I came
    > across this.
    > I understand the need for fallback definitions of the topology APIs
    > within the kernel, but I'm not sure I agree with exposing these things
    > in sysfs unconditionally -- the default values for physical_package_id
    > and core_id don't really make sense on powerpc (and other non-x86
    > architectures, I suspect).

    In what way are they wrong?

    > Would you object to a patch which exposes in sysfs only the topology
    > information which the architecture provides?

    I was primarily concerned with having the fallbacks available in-kernel.
    However, I don't think you will be doing user-space any favours by
    requiring checks for missing attributes for ever.


    Ben Hutchings, Senior Software Engineer, Solarflare Communications
    Not speaking for my employer; that's the marketing department's job.

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