Re: [RFC PATCH v1 0/8] SCHED_DEADLINE freq/cpu invariance and OPP selection

Rafael J. Wysocki
2017-07-06T21:15:50Z

On Wednesday, July 05, 2017 09:58:57 AM Juri Lelli wrote:
> Hi,
>
> v1 of the RFC set implementing frequency/cpu invariance and OPP selection for
> SCHED_DEADLINE [1]. The set is based on tip/sched/core as of today
> (72298e5c92c5), which now already includes Luca's "CPU reclaiming for
> SCHED_DEADLINE".
>
> Thanks a lot for reviewing RFCv0!
>
> Patches high level description:
>
> o [01-02]/08 add the necessary links to start accounting DEADLINE contribution
> to OPP selection
> o 03/08 it's a temporary solution to make possible (on ARM) to change
> frequency for DEADLINE tasks (that would possibly delay the SCHED_FIFO
> worker kthread); proper solution would be to be able to issue frequency
> transition from an atomic ctx
> o [04-05]/08 it's a schedutil change that copes with the fact that DEADLINE
> doesn't require periodic OPP selection triggering point
> o [06-07]/08 make arch_scale_{freq,cpu}_capacity() function available on !CONFIG_SMP
> configurations too
> o 08/08 implements frequency/cpu invariance for tasks' reservation
> parameters; which basically means that we implement GRUB-PA [2]
>
> Changes w.r.t. RFCv0:
>
> - rebase on tip/sched/core
> - make use of BW_SHIFT for calculations (Peter)
> - added a comment about guaranteed/requested frequency (Peter)
> - use a high bit for sched_flags SCHED_FLAG_SPECIAL hack; don't expose it to
> userspace and add comments (Peter)
> - refactor aggregation of utilization from scheduling classes
>
> Please have a look. Feedback and comments are, as usual, more than welcome.
>
> In case you would like to test this out:
>
> git://linux-arm.org/linux-jl.git upstream/deadline/freq-rfc-v1
>
> Best,
>
> - Juri
>
>
> Juri Lelli (8):
> sched/cpufreq_schedutil: make use of DEADLINE utilization signal
> sched/deadline: move cpu frequency selection triggering points
> sched/cpufreq_schedutil: make worker kthread be SCHED_DEADLINE
> sched/cpufreq_schedutil: split utilization signals
> sched/cpufreq_schedutil: always consider all CPUs when deciding next
> freq
> sched/sched.h: remove sd arch_scale_freq_capacity parameter
> sched/sched.h: move arch_scale_{freq,cpu}_capacity outside CONFIG_SMP
> sched/deadline: make bandwidth enforcement scale-invariant
>
> include/linux/sched.h | 1 +
> include/linux/sched/cpufreq.h | 2 --
> include/linux/sched/topology.h | 12 +++----
> kernel/sched/core.c | 15 ++++++--
> kernel/sched/cpufreq_schedutil.c | 77 ++++++++++++++++++++++++++--------------
> kernel/sched/deadline.c | 46 ++++++++++++++++++++----
> kernel/sched/fair.c | 4 +--
> kernel/sched/sched.h | 51 +++++++++++++++++++-------
> 8 files changed, 149 insertions(+), 59 deletions(-)

The schedutil changes in this series look OK to me, so please feel free to add

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

to these patches.

Thanks,
Rafael