On 01/31/2013 04:45 PM, Michael Wang wrote: > On 01/31/2013 04:24 PM, Michael Wang wrote: >> On 01/31/2013 03:40 PM, Namhyung Kim wrote: >>> On Thu, 31 Jan 2013 15:30:02 +0800, Michael Wang wrote: >>>> On 01/31/2013 02:58 PM, Namhyung Kim wrote: >>>>> But AFAIK the number of states in cpuidle is usually less than 10 so maybe >>>>> we can change the weight then, but there's no promise... >>>> >>>> And I just got another case we should take care: >>>> >>>> group 0 cpu 0 cpu 1 >>>> power index 8 power index 8 >>>> >>>> >>>> group 1 cpu 2 cpu 3 >>>> power index 0 load 15 >>>> >>>> so load of group 0 is 16 and group 1 is 15, but group 0 is better... >>> >>> Maybe it's not. The cpus in group 0 are in a lower power state so that >>> there will be a benefit to select cpu 2 from the power' PoV IMHO. Also >>> such a low power state has a longer exit latency so that we should >>> choose cpu2 to get a better performance and it's the basic idea of this >>> patchset I believe. >> >> Well, this case is just to notify that, we may face the comparison >> between load and index, not between index and index, I just doubt there >> won't be a rule which could take care both, besides, comparison between >> load and index is strange... > > Oh, I miss the point that you call it 'idle load', hmm...may be it could > works, if we could scale the current load number, then we will have more > 'space' for 'idle load'.
And some tips here: /* * Increase resolution of nice-level calculations for 64-bit architectures. * The extra resolution improves shares distribution and load balancing of * low-weight task groups (eg. nice +19 on an autogroup), deeper taskgroup * hierarchies, especially on larger systems. This is not a user-visible change * and does not change the user-interface for setting shares/weights. * * We increase resolution only if we have enough bits to allow this increased * resolution (i.e. BITS_PER_LONG > 32). The costs for increasing resolution * when BITS_PER_LONG <= 32 are pretty high and the returns do not justify the * increased costs. */ #if 0 /* BITS_PER_LONG > 32 -- currently broken: it increases power usage under light load */ # define SCHED_LOAD_RESOLUTION 10 # define scale_load(w) ((w) << SCHED_LOAD_RESOLUTION) # define scale_load_down(w) ((w) >> SCHED_LOAD_RESOLUTION) It mentioned some regressions, that's the history but sounds like a lot of testing is needed. Regards, Michael Wang > > Regards, > Michael Wang > >> >> Regards, >> Michael Wang >> >>> >>> Thanks, >>> Namhyung >>> -- >>> 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/ > -- 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/
