From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthias Kaehlcke Subject: Re: [PATCH v1 6/7] arm64: dts: sdm845: Increase alert trip point to 95 degrees Date: Wed, 9 Jan 2019 18:15:22 -0800 Message-ID: <20190110021522.GW261387@google.com> References: <041258d65883df964890249a24d2a4788c419304.1547078153.git.amit.kucheria@linaro.org> <20190110011533.GV261387@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <20190110011533.GV261387@google.com> Sender: linux-kernel-owner@vger.kernel.org To: Amit Kucheria Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, bjorn.andersson@linaro.org, viresh.kumar@linaro.org, edubezval@gmail.com, andy.gross@linaro.org, tdas@codeaurora.org, swboyd@chromium.org, dianders@chromium.org, David Brown , Rob Herring , Mark Rutland , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" List-Id: devicetree@vger.kernel.org On Wed, Jan 09, 2019 at 05:15:33PM -0800, Matthias Kaehlcke wrote: > Hi Amit, > > On Thu, Jan 10, 2019 at 05:30:55AM +0530, Amit Kucheria wrote: > > 75 degrees is too aggressive for throttling the CPU. After speaking to > > Qualcomm engineers, increase it to 95 degrees. > > > > Signed-off-by: Amit Kucheria > > --- > > arch/arm64/boot/dts/qcom/sdm845.dtsi | 16 ++++++++-------- > > 1 file changed, 8 insertions(+), 8 deletions(-) > > > > diff --git a/arch/arm64/boot/dts/qcom/sdm845.dtsi b/arch/arm64/boot/dts/qcom/sdm845.dtsi > > index c27cbd3bcb0a..29e823b0caf4 100644 > > --- a/arch/arm64/boot/dts/qcom/sdm845.dtsi > > +++ b/arch/arm64/boot/dts/qcom/sdm845.dtsi > > @@ -1692,7 +1692,7 @@ > > > > trips { > > cpu_alert0: trip0 { > > - temperature = <75000>; > > + temperature = <95000>; > > hysteresis = <2000>; > > type = "passive"; > > }; > > @@ -1713,7 +1713,7 @@ > > > > trips { > > cpu_alert1: trip0 { > > - temperature = <75000>; > > + temperature = <95000>; > > hysteresis = <2000>; > > type = "passive"; > > }; > > @@ -1734,7 +1734,7 @@ > > > > trips { > > cpu_alert2: trip0 { > > - temperature = <75000>; > > + temperature = <95000>; > > hysteresis = <2000>; > > type = "passive"; > > }; > > @@ -1755,7 +1755,7 @@ > > > > trips { > > cpu_alert3: trip0 { > > - temperature = <75000>; > > + temperature = <95000>; > > hysteresis = <2000>; > > type = "passive"; > > }; > > @@ -1776,7 +1776,7 @@ > > > > trips { > > cpu_alert4: trip0 { > > - temperature = <75000>; > > + temperature = <95000>; > > hysteresis = <2000>; > > type = "passive"; > > }; > > @@ -1797,7 +1797,7 @@ > > > > trips { > > cpu_alert5: trip0 { > > - temperature = <75000>; > > + temperature = <95000>; > > hysteresis = <2000>; > > type = "passive"; > > }; > > @@ -1818,7 +1818,7 @@ > > > > trips { > > cpu_alert6: trip0 { > > - temperature = <75000>; > > + temperature = <95000>; > > hysteresis = <2000>; > > type = "passive"; > > }; > > @@ -1839,7 +1839,7 @@ > > > > trips { > > cpu_alert7: trip0 { > > - temperature = <75000>; > > + temperature = <95000>; > > hysteresis = <2000>; > > type = "passive"; > > }; > > The change itself looks good to me, however I wonder if it would be > worth to eliminate redundancy and merge the current 8 thermal zones > into 2, one for the Silver and one for the Gold cluster (as done by > http://crrev.com/c/1381752). There is a single cooling device for > each cluster, so it's not clear to me if there is any gain from having > a separate thermal zone for each CPU. If it is important to monitor > the temperatures of the individual cores this can still be done by > configuring the thermal zone of the cluster with multiple thermal > sensors. I see your idea is to have a cooling device per CPU ("arm64: dts: sdm845: wireup the thermal trip points to cpufreq" / https://lore.kernel.org/patchwork/patch/1030742/), however that doesn't work as intended. Only two cpufreq 'devices' are created, one for CPU0 and one for CPU4. In consequence cpufreq->ready() only runs for these cores and only two cooling devices are registered. Since the cores of a cluster all run at the same frequency I also doubt if having multiple cooling devices would bring any benefits. Cheers Matthias