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    SubjectRe: [PATCH 2/2] powerpc: implement arch_scale_smt_power for Power7

    >> + if (cpu_has_feature(CPU_FTRS_POWER7) && weight == 4) {
    >>
    >
    > I think we should avoid using cpu_has_feature like this. It's better to
    > create a new feature and add it to POWER7 in the cputable, then check
    > for that here.
    >
    > The way that it is now, I think any CPU that has superset of the POWER7
    > features, will be true here. This is not what we want.
    >
    Any ideas for what to call this feature? ASYM_SMT4 ?
    >
    >> + smt_gain /= weight;
    >>
    >
    > This results in a PPC div, when most of the time it's going to be a
    > power of two divide. You've optimised the divides a few lines above
    > this, but not this one. Some consistency would be good.
    >
    >
    I can turn that into a conditional branch (case statement) with a shift
    for the common 1,2,4 cases which should cover all procs available today
    falling back to a divide for any theoretical future processors that do
    other numbers of threads.


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