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    SubjectRe: [PATCH 01/10] IB/ehca: Support for multiple event queues
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    Roland Dreier <rdreier@cisco.com> wrote on 16.07.2007 18:04:26:

    > It seems not quite right to me for the driver to advertise nr_eqs
    > completion vectors, but then if round-robin is turned on to ignore the
    > consumer's decision about which vector to use.

    The round-robin feature was primarily meant as a debug/evaluation feature;
    it is not supposed to be active by default. ULP programmers can, for
    example, quickly evaluate the performance increase that comp_vectors could
    give them, without changing their code. Without this debug option, the
    comp_vector policy is still up to the ULPs.

    > Maybe if round-robin is turned on you should report 0 as the number of
    > completion vectors?

    That sounds like a reasonable idea -- I'll change that right away.

    > Maybe the whole interface is broken and we should only be exposing
    > policies to consumers instead of the specific vector?

    If so, I think the policies should be handled by the IB core code instead
    of being re-invented by each driver. The IB core would then again pass
    actual comp_vector values to the driver.

    > I think I would rather hold off on multiple EQs for this merge window
    > and plan on having something really solid and thought-out for 2.6.24.

    It's your call, but the code is there and I don't expect it to change a
    lot later, so it could be used by others to get a first impression of
    what's possible using comp_vectors and to gather some experience with
    them.

    Regards,
    Joachim
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