Re: [PATCH 0/6 v6] sched: reflect sched_entity move into task_group's load

From: Andres Oportus
Date: Tue Nov 22 2016 - 13:50:24 EST


Tested-by: Andres Oportus <andresoportus@xxxxxxxxxx>

On Tue, Nov 22, 2016 at 9:55 AM, Andres Oportus
<andresoportus@xxxxxxxxxx> wrote:
>
> On Tue, Nov 22, 2016 at 9:52 AM, Andres Oportus
> <andresoportus@xxxxxxxxxx> wrote:
> >
> > I have back-ported these patches into Android with 4.4 kernel and tested
> > them on a Hikey device [1]. Back-ported patches used are enclosed.
> > I see equal or better performance across all tests.
> >
> > PELT below refers to https://android.googlesource.com/kernel/hikey-linaro at
> > android-hikey-linaro-4.4 caae63389787850e633eef67526443729c18451c
> > and WALT disabled (Android with PELT).
> > PELT+fixes refers to PELT + Vincent's patches back-ported.
> >
> > These are tests run using the Vellamo app [2], higher scores are better:
> >
> > Test PELT PELT+fixes Delta
> > MT Linpack native 126 131 3.97%
> > MT Linpack java 173 175 1.16%
> > MT Stream 5.10 158 158 0.00%
> > Membench 212 214 0.94%
> > Sysbench 174 196 12.64%
> > Parsec 202 207 2.48%
> >
> > These are "Jankbench" tests, real world use cases of special interest to
> > Android. Xth frame percentile indicates X % of frames rendered in Y ms
> > or less. Lower is better.
> >
> > Test PELT PELT+fixes Delta
> > listview scroll 90% 13.87 13.66 -1.54%
> > listview scroll 95% 14.80 14.58 -1.51%
> > listview scroll 99% 17.43 17.00 -2.53%
> > image listview scroll 90% 14.17 14.04 -0.93%
> > image listview scroll 95% 15.13 14.90 -1.54%
> > image listview scroll 99% 17.43 17.08 -2.05%
> > shadow grid 90% 16.40 16.28 -0.74%
> > shadow grid 95% 17.23 17.06 -1.00%
> > shadow grid 99% 23.07 23.44 1.58%
> > hi-hitrate text render 90% 28.77 28.62 -0.52%
> > hi-hitrate text render 95% 31.60 31.48 -0.38%
> > hi-hitrate text render 96% 41.53 41.10 -1.05%
> > low-hitrate text render 90% 28.97 28.66 -1.08%
> > low-hitrate text render 95% 32.10 31.66 -1.39%
> > low-hitrate text render 99% 41.70 41.38 -0.77%
> >
> > Andres
> >
> > [1] http://www.96boards.org/product/hikey
> > [2] https://play.google.com/store/apps/details?id=com.quicinc.vellamo
> >
> >
> >> From: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
> >> Date: Tue, Nov 8, 2016 at 12:26 AM
> >> Subject: [PATCH 0/6 v6] sched: reflect sched_entity move into task_group's load
> >> To: peterz@xxxxxxxxxxxxx, mingo@xxxxxxxxxx,
> >> linux-kernel@xxxxxxxxxxxxxxx, dietmar.eggemann@xxxxxxx
> >> Cc: yuyang.du@xxxxxxxxx, Morten.Rasmussen@xxxxxxx, pjt@xxxxxxxxxx,
> >> bsegall@xxxxxxxxxx, kernellwp@xxxxxxxxx, Vincent Guittot
> >> <vincent.guittot@xxxxxxxxxx>
> >>
> >>
> >> Ensure that the move of a sched_entity will be reflected in load and
> >> utilization of the task_group hierarchy.
> >>
> >> When a sched_entity moves between groups or CPUs, load and utilization
> >> of cfs_rq don't reflect the changes immediately but converge to new values.
> >> As a result, the metrics are no more aligned with the new balance of the
> >> load in the system and next decisions will have a biased view.
> >>
> >> This patchset synchronizes load/utilization of sched_entity with its child
> >> cfs_rq (se->my-q) only when tasks move to/from child cfs_rq:
> >> -move between task group
> >> -migration between CPUs
> >> Otherwise, PELT is updated as usual.
> >>
> >> This version doesn't include any changes related to discussion that have
> >> started during the review of the previous version about:
> >> - encapsulate the sequence for changing the property of a task
> >> - remove a cfs_rq from list during update_blocked_averages
> >> These topics don't gain anything from being added in this patchset as they
> >> are fairly independent and deserve a separate patch.
> >>
> >> Changes since v5:
> >> - factorize detach entity like for attach
> >> - fix add_positive
> >> - Fixed few coding style
> >>
> >> Changes since v4:
> >> - minor typo and commit message changes
> >> - move call to cfs_rq_clock_task(cfs_rq) in post_init_entity_util_avg
> >>
> >> Changes since v3:
> >> - Replaced the 2 arguments of update_load_avg by 1 flags argument
> >> - Propagated move in runnable_load_avg when sched_entity is already on_rq
> >> - Ensure that intermediate value will not reach memory when updating load and
> >> utilization
> >> - Optimize the the calculation of load_avg of the sched_entity
> >> - Fixed some typo
> >>
> >> Changes since v2:
> >> - Propagate both utilization and load
> >> - Synced sched_entity and se->my_q instead of adding the delta
> >>
> >> Changes since v1:
> >> - This patch needs the patch that fixes issue with rq->leaf_cfs_rq_list
> >> "sched: fix hierarchical order in rq->leaf_cfs_rq_list" in order to work
> >> correctly. I haven't sent them as a single patchset because the fix is
> >> independent of this one
> >> - Merge some functions that are always used together
> >> - During update of blocked load, ensure that the sched_entity is synced
> >> with the cfs_rq applying changes
> >> - Fix an issue when task changes its cpu affinity
> >>
> >> Vincent Guittot (6):
> >> sched: factorize attach/detach entity
> >> sched: fix hierarchical order in rq->leaf_cfs_rq_list
> >> sched: factorize PELT update
> >> sched: propagate load during synchronous attach/detach
> >> sched: propagate asynchrous detach
> >> sched: fix task group initialization
> >>
> >> kernel/sched/core.c | 1 +
> >> kernel/sched/fair.c | 393 ++++++++++++++++++++++++++++++++++++++++-----------
> >> kernel/sched/sched.h | 2 +
> >> 3 files changed, 316 insertions(+), 80 deletions(-)
> >>
> >> --
> >> 2.7.4
> >
> >