linux-kernel - Re: [Patch v3 0/6] Introduce LMh driver for Qualcomm SoCs

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Message-ID: <ff6fc8d4-38e9-86ea-f689-609668c53196@kali.org>
Date:   Tue, 27 Jul 2021 12:43:49 -0500
From:   Steev Klimaszewski <steev@...i.org>
To:     Thara Gopinath <thara.gopinath@...aro.org>, agross@...nel.org,
        bjorn.andersson@...aro.org, rui.zhang@...el.com,
        daniel.lezcano@...aro.org, viresh.kumar@...aro.org,
        rjw@...ysocki.net, robh+dt@...nel.org
Cc:     tdas@...eaurora.org, mka@...omium.org,
        linux-arm-msm@...r.kernel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [Patch v3 0/6] Introduce LMh driver for Qualcomm SoCs


On 7/27/21 10:29 AM, Thara Gopinath wrote:
>
>
> On 7/21/21 11:14 PM, Steev Klimaszewski wrote:
>> Hi Thara!
>>
>> On 7/8/21 7:06 AM, Thara Gopinath wrote:
>>> Limits Management Hardware(LMh) is a hardware infrastructure on some
>>> Qualcomm SoCs that can enforce temperature and current limits as
>>> programmed
>>> by software for certain IPs like CPU. On many newer SoCs LMh is
>>> configured
>>> by firmware/TZ and no programming is needed from the kernel side.
>>> But on
>>> certain SoCs like sdm845 the firmware does not do a complete
>>> programming of
>>> the h/w block. On such SoCs kernel software has to explicitly set up
>>> the
>>> temperature limits and turn on various monitoring and enforcing
>>> algorithms
>>> on the hardware.
>>>
>>> Introduce support for enabling and programming various limit
>>> settings and
>>> monitoring capabilities of Limits Management Hardware(LMh)
>>> associated with
>>> cpu clusters. Also introduce support in cpufreq hardware driver to
>>> monitor
>>> the interrupt associated with cpu frequency throttling so that this
>>> information can be conveyed to the schdeuler via thermal pressure
>>> interface.
>>>
>>> With this patch series following cpu performance improvement(30-70%) is
>>> observed on sdm845. The reasoning here is that without LMh being
>>> programmed
>>> properly from the kernel, the default settings were enabling thermal
>>> mitigation for CPUs at too low a temperature (around 70-75 degree
>>> C).  This
>>> in turn meant that many a time CPUs were never actually allowed to
>>> hit the
>>> maximum possible/required frequencies.
>>>
>>> UnixBench whets and dhry (./Run whets dhry)
>>> System Benchmarks Index Score
>>>
>>>                  Without LMh Support             With LMh Support
>>> 1 copy test     1353.7                          1773.2
>>>
>>> 8 copy tests    4473.6                          7402.3
>>>
>>> Sysbench cpu
>>> sysbench cpu --threads=8 --time=60 --cpu-max-prime=100000 run
>>>
>>>                  Without LMh Support             With LMh Support
>>> Events per
>>> second                  355                             614
>>>
>>> Avg Latency(ms)         21.84                           13.02
>>>
>>> v2->v3:
>>>     - Included patch adding dt binding documentation for LMh nodes.
>>>     - Rebased to v5.13
>>>
>>> Thara Gopinath (6):
>>>    firmware: qcom_scm: Introduce SCM calls to access LMh
>>>    thermal: qcom: Add support for LMh driver
>>>    cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support
>>>    arm64: boot: dts: qcom: sdm45: Add support for LMh node
>>>    arm64: boot: dts: qcom: sdm845: Remove cpufreq cooling devices
>>> for CPU
>>>      thermal zones
>>>    dt-bindings: thermal: Add dt binding for QCOM LMh
>>>
>>>   .../devicetree/bindings/thermal/qcom-lmh.yaml | 100 ++++++++
>>>   arch/arm64/boot/dts/qcom/sdm845.dtsi          | 162 ++----------
>>>   drivers/cpufreq/qcom-cpufreq-hw.c             | 118 +++++++++
>>>   drivers/firmware/qcom_scm.c                   |  58 +++++
>>>   drivers/firmware/qcom_scm.h                   |   4 +
>>>   drivers/thermal/qcom/Kconfig                  |  10 +
>>>   drivers/thermal/qcom/Makefile                 |   1 +
>>>   drivers/thermal/qcom/lmh.c                    | 239
>>> ++++++++++++++++++
>>>   include/linux/qcom_scm.h                      |  14 +
>>>   9 files changed, 570 insertions(+), 136 deletions(-)
>>>   create mode 100644
>>> Documentation/devicetree/bindings/thermal/qcom-lmh.yaml
>>>   create mode 100644 drivers/thermal/qcom/lmh.c
>>>
>> I've been using these patches on a 5.13 kernel
>> (https://github.com/steev/linux/tree/linux-5.13.y - while trying to
>> track down a different issue, while playing a video on youtube, as well
>> as compressing a 9.2GB file with xz, I got the following
>
> Hi Steev,
>
> Thanks for testing this. I was unable to reproduce this. I have posted
> v4 moving the interrupt handling in qcom-cpufreq-hw to threaded
> interrupt handler and hopefully this should fix the issue. It will be
> great if you can test and let me know.
>
Hi Thara,

I've been testing v4 for a little bit here, and so far I can't seem to
get it to reproduce anymore.  I will keep trying but fingers crossed
that that did the trick.

For setup, I'm using https://github.com/steev/linux/tree/linux-5.13.y
with the "distro_defconfig" configuration here on my c630s.  I'm also
running https://github.com/steev/scheduler as a systemd service.  So far
I've been able to sleep/suspend without issue while running "make
-j$(nproc) deb-pkg" in those kernel sources as well as `xz
--memlimit-compress=50 -T 4 imagefile.img" on a 9.2GB file at the same
time.  One system is running the Budgie desktop on top of Xorg, and the
other is running Gnome 3.38 on top of Wayland.

-- steev