Re: [PATCH v3 0/5] sched/fair: Task placement biasing using uclamp

From: Dietmar Eggemann
Date: Thu Dec 12 2019 - 10:06:52 EST


On 11/12/2019 12:38, Valentin Schneider wrote:
> Hi,
>
> While uclamp restrictions currently only impact schedutil's frequency
> selection, it would make sense to also let them impact CPU selection in
> asymmetric topologies. This would let us steer specific tasks towards
> certain CPU capacities regardless of their actual utilization - I give a
> few examples in patch 4.
>
> The first three patches are mainly cleanups, the meat of the thing is
> in patches 4 and 5.
>
> Note that this is in the same spirit as what Patrick had proposed for EAS
> on Android [1]
>
> [1]: https://android.googlesource.com/kernel/common/+/b61876ed122f816660fe49e0de1b7ee4891deaa2%5E%21

Reviewed-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Tested-By: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>

Tested on Juno-r0 (Arm64) cpumask [0x3f] w/ big [0x06], LITTLE [0x39]
[orig cpu capacity big,LITTLE: 1024,446] and rt-app

4 periodic tasks runtime/period [800/16000], per task uclamp_min/max
[600,1024]

w/o uclamp: EAS puts the tasks on LITTLE CPUs [0x39]
w/ uclamp: EAS puts the tasks on big CPUs [0x06]