Re: [RFC PATCH 0/3] CFS idle injection

From	Juri Lelli <juri.lelli@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH 0/3] CFS idle injection
Date	2015-11-10 11:10 +0100
Message-ID	<qte2e-3Ga-19@gated-at.bofh.it> (permalink)
References	(3 earlier) <qrpO9-5g9-1@gated-at.bofh.it> <qrSwO-71N-13@gated-at.bofh.it> <qrWh4-13l-15@gated-at.bofh.it> <qsTh8-5UJ-17@gated-at.bofh.it> <qsVsC-7v9-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

Hi,

On 9 November 2015 at 14:15, Peter Zijlstra <peterz@infradead.org> wrote:
> On Mon, Nov 09, 2015 at 11:56:51AM +0000, Punit Agrawal wrote:
>> Jacob Pan <jacob.jun.pan@linux.intel.com> writes:
>> > My take is that RT and throttling will never go well together since they
>> > are conflicting in principle.
>>
>> I am not sure I follow. If RT (or other higher priority classes) can't
>> be throttled then the CPUs are not able to contribute towards
>> constraining power consumption and hence temperature.
>>
>> This is especially true in certain platforms where tasks belong to the
>> RT class to maintain user experience, e.g., audio and video.
>
> Audio/Video playback generally doesn't take a _lot_ of time these days.
> What is important though is _when_ it happens.
>
> And media playback typically already has a very well defined and stable
> cadence (24Hz or whatnot).  What you want is for your idle injector to
> sync up with that, not disrupt it.
>

Do you think that using SCHED_DEADLINE here would be completely
foolish? I mean, we would have the duty_cycle/period thing for free, it
would be know to the scheduler (as to maybe address Thomas' concerns)
and we could think to make idle injection part of system analysis (for
the soft-RT use cases).

Thanks,

- Juri

> For other workloads, missing a deadline is about as bad as destroying
> the chip, complete system shutdown might be safer than getting delayed.
> (The very tired scenario of a saw, a laser and your finger; you want to
> shut down the entire machine rather than just cut off your finger.)
>
>
>
> --
> 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/
--
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/

Thread

[RFC PATCH 0/3] CFS idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-03 01:20 +0100
  [RFC PATCH 3/3] sched: introduce synchronized idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-03 01:20 +0100
    Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Peter Zijlstra <peterz@infradead.org> - 2015-11-03 14:40 +0100
      Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-03 15:20 +0100
      Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-03 17:50 +0100
        Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Peter Zijlstra <peterz@infradead.org> - 2015-11-05 11:20 +0100
          Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Arjan van de Ven <arjan@linux.intel.com> - 2015-11-05 15:30 +0100
            Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Peter Zijlstra <peterz@infradead.org> - 2015-11-05 15:40 +0100
              Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Peter Zijlstra <peterz@infradead.org> - 2015-11-05 15:50 +0100
              Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Arjan van de Ven <arjan@linux.intel.com> - 2015-11-05 16:30 +0100
                Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Peter Zijlstra <peterz@infradead.org> - 2015-11-05 18:00 +0100
                Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Thomas Gleixner <tglx@linutronix.de> - 2015-11-05 20:00 +0100
                Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Thomas Gleixner <tglx@linutronix.de> - 2015-11-05 19:50 +0100
              Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-05 16:40 +0100
                Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Arjan van de Ven <arjan@linux.intel.com> - 2015-11-05 17:10 +0100
          Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-05 20:30 +0100
            Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-05 20:40 +0100
      Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Peter Zijlstra <peterz@infradead.org> - 2015-11-05 15:10 +0100
        Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-06 00:50 +0100
          Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Peter Zijlstra <peterz@infradead.org> - 2015-11-06 08:50 +0100
            Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-07 01:00 +0100
              Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-10 01:30 +0100
  [RFC PATCH 2/3] timer: relax tick stop in idle entry Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-03 01:20 +0100
  Re: [RFC PATCH 0/3] CFS idle injection Eduardo Valentin <edubezval@gmail.com> - 2015-11-04 07:10 +0100
    Re: [RFC PATCH 0/3] CFS idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-04 18:00 +0100
      Re: [RFC PATCH 0/3] CFS idle injection Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> - 2015-11-04 18:10 +0100
        Re: [RFC PATCH 0/3] CFS idle injection Eduardo Valentin <edubezval@gmail.com> - 2015-11-04 19:50 +0100
      Re: [RFC PATCH 0/3] CFS idle injection Peter Zijlstra <peterz@infradead.org> - 2015-11-05 11:20 +0100
        Re: [RFC PATCH 0/3] CFS idle injection Punit Agrawal <punit.agrawal@arm.com> - 2015-11-06 18:00 +0100
          Re: [RFC PATCH 0/3] CFS idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-06 22:00 +0100
            Re: [RFC PATCH 0/3] CFS idle injection Punit Agrawal <punit.agrawal@arm.com> - 2015-11-09 13:00 +0100
              Re: [RFC PATCH 0/3] CFS idle injection Peter Zijlstra <peterz@infradead.org> - 2015-11-09 15:20 +0100
                Re: [RFC PATCH 0/3] CFS idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-09 15:50 +0100
                Re: [RFC PATCH 0/3] CFS idle injection Juri Lelli <juri.lelli@gmail.com> - 2015-11-10 11:10 +0100
                Re: [RFC PATCH 0/3] CFS idle injection Peter Zijlstra <peterz@infradead.org> - 2015-11-10 11:40 +0100
                Re: [RFC PATCH 0/3] CFS idle injection Juri Lelli <juri.lelli@arm.com> - 2015-11-10 12:00 +0100
              Re: [RFC PATCH 0/3] CFS idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-09 15:40 +0100
        Re: [RFC PATCH 0/3] CFS idle injection Dietmar Eggemann <dietmar.eggemann@arm.com> - 2015-11-06 19:40 +0100
          Re: [RFC PATCH 0/3] CFS idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-06 20:20 +0100
            Re: [RFC PATCH 0/3] CFS idle injection Dietmar Eggemann <dietmar.eggemann@arm.com> - 2015-11-06 23:00 +0100
              Re: [RFC PATCH 0/3] CFS idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-09 22:30 +0100
                Re: [RFC PATCH 0/3] CFS idle injection Peter Zijlstra <peterz@infradead.org> - 2015-11-09 22:50 +0100

csiph-web