Messages in this thread |  | | | Date | Wed, 20 Jan 2010 16:09:30 -0600 | | From | Joel Schopp <> | | Subject | Re: [PATCH 2/2] powerpc: implement arch_scale_smt_power for Power7 |
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>> + 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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