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Groups > linux.kernel > #1224114
| From | Morten Rasmussen <morten.rasmussen@arm.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig |
| Date | 2015-09-14 15:00 +0200 |
| Message-ID | <q8Bwu-6Es-29@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <q71ln-7gf-1@gated-at.bofh.it> <q76XN-6I3-39@gated-at.bofh.it> <q7rIS-4kB-21@gated-at.bofh.it> <q7tKF-7d0-1@gated-at.bofh.it> <q7zZM-7Wu-9@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Fri, Sep 11, 2015 at 10:05:53AM -0700, bsegall@google.com wrote:
> Morten Rasmussen <morten.rasmussen@arm.com> writes:
>
> > On Fri, Sep 11, 2015 at 08:28:25AM +0800, Yuyang Du wrote:
> >> diff --git a/include/linux/sched.h b/include/linux/sched.h
> >> index 119823d..55a7b93 100644
> >> --- a/include/linux/sched.h
> >> +++ b/include/linux/sched.h
> >> @@ -912,7 +912,7 @@ enum cpu_idle_type {
> >> /*
> >> * Increase resolution of cpu_capacity calculations
> >> */
> >> -#define SCHED_CAPACITY_SHIFT 10
> >> +#define SCHED_CAPACITY_SHIFT SCHED_RESOLUTION_SHIFT
> >> #define SCHED_CAPACITY_SCALE (1L << SCHED_CAPACITY_SHIFT)
> >>
> >> /*
> >> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> >> index 68cda11..d27cdd8 100644
> >> --- a/kernel/sched/sched.h
> >> +++ b/kernel/sched/sched.h
> >> @@ -40,6 +40,9 @@ static inline void update_cpu_load_active(struct rq *this_rq) { }
> >> */
> >> #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
> >>
> >> +# define SCHED_RESOLUTION_SHIFT 10
> >> +# define SCHED_RESOLUTION_SCALE (1L << SCHED_RESOLUTION_SHIFT)
> >> +
> >> /*
> >> * Increase resolution of nice-level calculations for 64-bit architectures.
> >> * The extra resolution improves shares distribution and load balancing of
> >> @@ -53,16 +56,15 @@ static inline void update_cpu_load_active(struct rq *this_rq) { }
> >> * 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)
> >> +# define SCHED_LOAD_SHIFT (SCHED_RESOLUTION_SHIFT + SCHED_RESOLUTION_SHIFT)
> >> +# define scale_load(w) ((w) << SCHED_RESOLUTION_SHIFT)
> >> +# define scale_load_down(w) ((w) >> SCHED_RESOLUTION_SHIFT)
> >> #else
> >> -# define SCHED_LOAD_RESOLUTION 0
> >> +# define SCHED_LOAD_SHIFT (SCHED_RESOLUTION_SHIFT)
> >> # define scale_load(w) (w)
> >> # define scale_load_down(w) (w)
> >> #endif
> >>
> >> -#define SCHED_LOAD_SHIFT (10 + SCHED_LOAD_RESOLUTION)
> >> #define SCHED_LOAD_SCALE (1L << SCHED_LOAD_SHIFT)
> >>
> >> #define NICE_0_LOAD SCHED_LOAD_SCALE
> >
> > I think this is pretty much the required relationship between all the
> > SHIFTs and SCALEs that Peter checked for in his #if-#error thing
> > earlier, so no disagreements from my side :-)
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> > Please read the FAQ at http://www.tux.org/lkml/
>
> SCHED_LOAD_RESOLUTION and the non-SLR part of SCHED_LOAD_SHIFT are not
> required to be the same value and should not be conflated.
>
> In particular, since cgroups are on the same timeline as tasks and their
> shares are not scaled by SCHED_LOAD_SHIFT in any way (but are scaled so
> that SCHED_LOAD_RESOLUTION is invisible), changing that part of
> SCHED_LOAD_SHIFT would cause issues, since things can assume that nice-0
> = 1024. However changing SCHED_LOAD_RESOLUTION would be fine, as that is
> an internal value to the kernel.
>
> In addition, changing the non-SLR part of SCHED_LOAD_SHIFT would require
> recomputing all of prio_to_weight/wmult for the new NICE_0_LOAD.
I think I follow, but doesn't that mean that the current code is broken
too? NICE_0_LOAD changes if you change SCHED_LOAD_RESOLUTION:
#define SCHED_LOAD_SHIFT (10 + SCHED_LOAD_RESOLUTION)
#define SCHED_LOAD_SCALE (1L << SCHED_LOAD_SHIFT)
#define NICE_0_LOAD SCHED_LOAD_SCALE
#define NICE_0_SHIFT SCHED_LOAD_SHIFT
To me it sounds like we need to define it the other way around:
#define NICE_0_SHIFT 10
#define NICE_0_LOAD (1L << NICE_0_SHIFT)
and then add any additional resolution bits from there to ensure that
NICE_0_LOAD and the prio_to_weight/wmult tables are unchanged.
--
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Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Dietmar Eggemann <dietmar.eggemann@arm.com> - 2015-09-07 17:40 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Vincent Guittot <vincent.guittot@linaro.org> - 2015-09-07 18:30 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Dietmar Eggemann <dietmar.eggemann@arm.com> - 2015-09-07 21:00 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Peter Zijlstra <peterz@infradead.org> - 2015-09-07 21:50 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Dietmar Eggemann <dietmar.eggemann@arm.com> - 2015-09-08 14:50 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Vincent Guittot <vincent.guittot@linaro.org> - 2015-09-08 09:30 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Peter Zijlstra <peterz@infradead.org> - 2015-09-08 14:30 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Peter Zijlstra <peterz@infradead.org> - 2015-09-08 15:00 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Vincent Guittot <vincent.guittot@linaro.org> - 2015-09-08 16:10 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Morten Rasmussen <morten.rasmussen@arm.com> - 2015-09-08 16:40 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Vincent Guittot <vincent.guittot@linaro.org> - 2015-09-08 16:50 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Morten Rasmussen <morten.rasmussen@arm.com> - 2015-09-08 16:30 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Peter Zijlstra <peterz@infradead.org> - 2015-09-08 17:40 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig bsegall@google.com - 2015-09-10 00:30 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Morten Rasmussen <morten.rasmussen@arm.com> - 2015-09-10 13:10 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Vincent Guittot <vincent.guittot@linaro.org> - 2015-09-10 13:20 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Morten Rasmussen <morten.rasmussen@arm.com> - 2015-09-10 14:10 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Yuyang Du <yuyang.du@intel.com> - 2015-09-11 10:40 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig bsegall@google.com - 2015-09-10 19:30 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Morten Rasmussen <morten.rasmussen@arm.com> - 2015-09-08 18:50 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Peter Zijlstra <peterz@infradead.org> - 2015-09-09 11:50 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Peter Zijlstra <peterz@infradead.org> - 2015-09-09 11:50 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Morten Rasmussen <morten.rasmussen@arm.com> - 2015-09-09 13:10 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Morten Rasmussen <morten.rasmussen@arm.com> - 2015-09-11 19:20 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Peter Zijlstra <peterz@infradead.org> - 2015-09-17 12:00 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Peter Zijlstra <peterz@infradead.org> - 2015-09-17 12:50 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Yuyang Du <yuyang.du@intel.com> - 2015-09-21 11:10 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig bsegall@google.com - 2015-09-21 19:40 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Yuyang Du <yuyang.du@intel.com> - 2015-09-22 09:30 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Leo Yan <leo.yan@linaro.org> - 2015-09-11 09:50 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Morten Rasmussen <morten.rasmussen@arm.com> - 2015-09-11 12:00 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Leo Yan <leo.yan@linaro.org> - 2015-09-11 16:20 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Yuyang Du <yuyang.du@intel.com> - 2015-09-10 05:00 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Peter Zijlstra <peterz@infradead.org> - 2015-09-10 12:10 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Vincent Guittot <vincent.guittot@linaro.org> - 2015-09-08 15:50 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Peter Zijlstra <peterz@infradead.org> - 2015-09-08 16:20 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Vincent Guittot <vincent.guittot@linaro.org> - 2015-09-08 17:20 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Dietmar Eggemann <dietmar.eggemann@arm.com> - 2015-09-08 15:00 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Vincent Guittot <vincent.guittot@linaro.org> - 2015-09-08 16:10 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Dietmar Eggemann <dietmar.eggemann@arm.com> - 2015-09-08 16:30 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Yuyang Du <yuyang.du@intel.com> - 2015-09-10 06:10 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Peter Zijlstra <peterz@infradead.org> - 2015-09-10 12:10 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Yuyang Du <yuyang.du@intel.com> - 2015-09-11 10:20 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Morten Rasmussen <morten.rasmussen@arm.com> - 2015-09-11 12:30 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig bsegall@google.com - 2015-09-11 19:10 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Yuyang Du <yuyang.du@intel.com> - 2015-09-12 04:20 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig bsegall@google.com - 2015-09-14 19:40 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Morten Rasmussen <morten.rasmussen@arm.com> - 2015-09-14 15:00 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig bsegall@google.com - 2015-09-14 19:40 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Yuyang Du <yuyang.du@intel.com> - 2015-09-15 08:50 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig bsegall@google.com - 2015-09-15 19:20 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Yuyang Du <yuyang.du@intel.com> - 2015-09-16 04:30 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig bsegall@google.com - 2015-09-16 19:10 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Yuyang Du <yuyang.du@intel.com> - 2015-09-17 12:30 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Morten Rasmussen <morten.rasmussen@arm.com> - 2015-09-15 10:40 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Peter Zijlstra <peterz@infradead.org> - 2015-09-16 17:50 +0200
Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig Peter Zijlstra <peterz@infradead.org> - 2015-09-08 13:50 +0200
[tip:sched/core] sched/fair: Get rid of scaling utilization by capacity_orig tip-bot for Dietmar Eggemann <tipbot@zytor.com> - 2015-09-13 13:10 +0200
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