On 11 July 2014 22:12, Peter Zijlstra <pet...@infradead.org> wrote: > On Fri, Jul 11, 2014 at 07:39:29PM +0200, Vincent Guittot wrote: >> In my mind, arch_scale_cpu_freq was intend to scale the capacity of >> the CPU according to the current dvfs operating point. >> As it's no more use anywhere now that we have arch_scale_cpu, we could >> probably remove it .. and see when it will become used. > > I probably should have written comments when I wrote that code, but it > was meant to be used only where, as described above, we limit things. > Ondemand and such, which will temporarily decrease freq, will ramp it up > again at demand, and therefore lowering the capacity will skew things. > > You'll put less load on because its run slower, and then you'll run it > slower because there's less load on -> cyclic FAIL. > >> > In that same discussion ISTR a suggestion about adding avg_running time, >> > as opposed to the current avg_runnable. The sum of avg_running should be >> > much more accurate, and still react correctly to migrations. >> >> I haven't look in details but I agree that avg_running would be much >> more accurate than avg_runnable and should probably fit the >> requirement. Does it means that we could re-add the avg_running (or >> something similar) that has disappeared during the review of load avg >> tracking patchset ? > > Sure, I think we killed it there because there wasn't an actual use for > it and I'm always in favour of stripping everything to their bare bones, > esp big and complex things. > > And then later, add things back once we have need for it.
Ok, i'm going to look how to add it back taking nto account current Yuyang's rework of load_avg > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
