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Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig

From Vincent Guittot <vincent.guittot@linaro.org>
Newsgroups linux.kernel
Subject Re: [PATCH 5/6] sched/fair: Get rid of scaling utilization by capacity_orig
Date 2015-09-08 17:20 +0200
Message-ID <q6sQF-80Q-3@gated-at.bofh.it> (permalink)
References (5 earlier) <q69O1-5Bh-5@gated-at.bofh.it> <q6lvQ-5SG-21@gated-at.bofh.it> <q6qca-48n-43@gated-at.bofh.it> <q6rrA-5QO-7@gated-at.bofh.it> <q6rUC-6Ec-29@gated-at.bofh.it>
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On 8 September 2015 at 16:10, Peter Zijlstra <peterz@infradead.org> wrote:
> On Tue, Sep 08, 2015 at 03:39:37PM +0200, Vincent Guittot wrote:
>> > Now, given all that, units are a complete mess here, and I'd not mind
>> > something like:
>> >
>> > #if (SCHED_LOAD_SHIFT - SCHED_LOAD_RESOLUTION) != SCHED_CAPACITY_SHIFT
>> > #error "something usefull"
>> > #endif
>>
>> In this case why not simply doing
>> #define SCHED_CAPACITY_SHIFT SCHED_LOAD_SHIFT
>> or the opposite ?
>
> Sadly not enough; aside from the fact that we really should do !0
> LOAD_RESOLUTION on 64bit, the whole magic tables (runnable_avg_yN_*[])
> and LOAD_AVG_MAX* values rely on the unit being 1<<10.

ah yes, i forgot to take into account the LOAD_RESOLUTION.

So after some more thinking,  i finally don't see where in the code,
we will have a issue if SCHED_CAPACITY_SHIFT is not equal to
(SCHED_LOAD_SHIFT - SCHED_LOAD_RESOLUTION) or not equal to 10 with the
respect of using a value that doesn't overflow the variables

Regards,
Vincent

>
> So regardless of defining one in terms of the other, we should check
> both are in fact 10 and error out otherwise.
>
> Changing them must involve recomputing these numbers or otherwise
> mucking about with shifts to ensure its back to 10 when we do this load
> muck.
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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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