lkml.org 
[lkml]   [2018]   [Oct]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [RFC PATCH 0/7] Introduce thermal pressure
From
Date
Hi Daniel,

On 10/10/2018 06:54 PM, Daniel Lezcano wrote:
> On 10/10/2018 17:35, Lukasz Luba wrote:
>> Hi Thara,
>>
>> I have run it on Exynos5433 mainline.
>> When it is enabled with step_wise thermal governor,
>> some of my tests are showing ~30-50% regression (i.e. hackbench),
>> dhrystone ~10%.
>>
>> Could you tell me which thermal governor was used in your case?
>> Please also share the name of that benchmark, i will give it a try.
>> Is it single threaded compute-intensive?
>
> aobench AFAICT
>
> It would be interesting if you can share the thermal profile of your board.
>
Thanks for the benchmark name.
It was tested on Samsung TM2 device with Exynos 5433 with debian.
Thermal stuff you can find in mainline:
arch/arm64/boot/dts/exynos/exynos5433-tmu.dtsi

Regards,
Lukasz

>
>> On 10/09/2018 06:24 PM, Thara Gopinath wrote:
>>> Thermal governors can respond to an overheat event for a cpu by
>>> capping the cpu's maximum possible frequency. This in turn
>>> means that the maximum available compute capacity of the
>>> cpu is restricted. But today in linux kernel, in event of maximum
>>> frequency capping of a cpu, the maximum available compute
>>> capacity of the cpu is not adjusted at all. In other words, scheduler
>>> is unware maximum cpu capacity restrictions placed due to thermal
>>> activity. This patch series attempts to address this issue.
>>> The benefits identified are better task placement among available
>>> cpus in event of overheating which in turn leads to better
>>> performance numbers.
>>>
>>> The delta between the maximum possible capacity of a cpu and
>>> maximum available capacity of a cpu due to thermal event can
>>> be considered as thermal pressure. Instantaneous thermal pressure
>>> is hard to record and can sometime be erroneous as there can be mismatch
>>> between the actual capping of capacity and scheduler recording it.
>>> Thus solution is to have a weighted average per cpu value for thermal
>>> pressure over time. The weight reflects the amount of time the cpu has
>>> spent at a capped maximum frequency. To accumulate, average and
>>> appropriately decay thermal pressure, this patch series uses pelt
>>> signals and reuses the available framework that does a similar
>>> bookkeeping of rt/dl task utilization.
>>>
>>> Regarding testing, basic build, boot and sanity testing have been
>>> performed on hikey960 mainline kernel with debian file system.
>>> Further aobench (An occlusion renderer for benchmarking realworld
>>> floating point performance) showed the following results on hikey960
>>> with debain.
>>>
>>> Result Standard Standard
>>> (Time secs) Error Deviation
>>> Hikey 960 - no thermal pressure applied 138.67 6.52 11.52%
>>> Hikey 960 - thermal pressure applied 122.37 5.78 11.57%
>>>
>>> Thara Gopinath (7):
>>> sched/pelt: Add option to make load and util calculations frequency
>>> invariant
>>> sched/pelt.c: Add support to track thermal pressure
>>> sched: Add infrastructure to store and update instantaneous thermal
>>> pressure
>>> sched: Initialize per cpu thermal pressure structure
>>> sched/fair: Enable CFS periodic tick to update thermal pressure
>>> sched/fair: update cpu_capcity to reflect thermal pressure
>>> thermal/cpu-cooling: Update thermal pressure in case of a maximum
>>> frequency capping
>>>
>>> drivers/base/arch_topology.c | 1 +
>>> drivers/thermal/cpu_cooling.c | 20 ++++++++++++-
>>> include/linux/sched.h | 14 +++++++++
>>> kernel/sched/Makefile | 2 +-
>>> kernel/sched/core.c | 2 ++
>>> kernel/sched/fair.c | 4 +++
>>> kernel/sched/pelt.c | 40 ++++++++++++++++++--------
>>> kernel/sched/pelt.h | 7 +++++
>>> kernel/sched/sched.h | 1 +
>>> kernel/sched/thermal.c | 66 +++++++++++++++++++++++++++++++++++++++++++
>>> kernel/sched/thermal.h | 13 +++++++++
>>> 11 files changed, 157 insertions(+), 13 deletions(-)
>>> create mode 100644 kernel/sched/thermal.c
>>> create mode 100644 kernel/sched/thermal.h
>>>
>
>

\
 
 \ /
  Last update: 2018-10-11 09:36    [W:0.165 / U:1.560 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site