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From:   Vincent Guittot <vincent.guittot@linaro.org>
Date:   Wed, 11 Jul 2018 10:27:09 +0200
Message-ID: <CAKfTPtBMWCT+sy0WQ7cH8Z-On+NH5NO7u3v7eLkOp0pZ+2gKGg@mail.gmail.com>
Subject: Re: [PATCH] arm64: hikey960: update idle-states
To:     Leo Yan <leo.yan@linaro.org>
Cc:     Wei Xu <xuwei5@hisilicon.com>, Rob Herring <robh+dt@kernel.org>,
        LAK <linux-arm-kernel@lists.infradead.org>,
        devicetree@vger.kernel.org,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Daniel Lezcano <daniel.lezcano@linaro.org>
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Sender: linux-kernel-owner@vger.kernel.org
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Hi Leo,

On Sun, 8 Jul 2018 at 16:02, <leo.yan@linaro.org> wrote:
>
> Hi Vincent,
>
> On Fri, Jul 06, 2018 at 08:57:26AM +0200, Vincent Guittot wrote:
> > Update entry/exit latency and residency time of hikey960 to use more
> > realistic figures based on unitary tests done on the platform.
> >
> > The complete results (in us) :
> >                   big cluster
> >                   cluster  CPU
> > max entry latency     800  400
> > max exit latency     2900  550
> > residency  903Mhz    5000 1500
> > residency 2363Mhz       0 1500
> >
> >                   little cluster
> >                   cluster  CPU
> > max entry latency     500  400
> > max exit latency     1600  650
> > residency  533Mhz    8000 4500
> > residency 1844Mhz       0 1500
> >
> > We can see that the residency time depends of the running OPP which is not
> > handled for now. Then we also have to take into account the constraint of
> > a residency time shorter than the tick to get full advantage of idle loop
> > reordering(tick is stopped if idle duration is higher than tick period).
> > Finally the selected residency value are :
> >                  big cluster
> >                   cluster  CPU
> > residency            3700 1500
> >
> >                   little cluster
> >                   cluster  CPU
> > residency            3500 1500
> >
> > A simple test with a task waking up every 11,111ms shows improvement:
>
> Should s/11,111ms/11.111ms ?

As Daniel explained, I have used the french notation. Will use the
other one in the next version

>
> > - 5% a lowest OPP
> > - 22% at highest OPP
> >
> > The period has been chosen:
> > - to be shorter than old cluster residency time and longer than new
> > residency time od cluster off C-state
>
> Should s/od/of/ ?

Yes

>
> Except these two minor typos, the patch is very good improvement.
>
> Reviewed-by: Leo Yan <leo.yan@linaro.org>

I'm going to send a new version with fix in the commit

Thanks
>
> > - to prevent any sync with tick (4ms) when running tests that can add
> > some variances between tests
> >
> > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> > ---
> >  arch/arm64/boot/dts/hisilicon/hi3660.dtsi | 45 ++++++++++++++++++-------------
> >  1 file changed, 27 insertions(+), 18 deletions(-)
> >
> > diff --git a/arch/arm64/boot/dts/hisilicon/hi3660.dtsi b/arch/arm64/boot/dts/hisilicon/hi3660.dtsi
> > index 421d454..890d23e 100644
> > --- a/arch/arm64/boot/dts/hisilicon/hi3660.dtsi
> > +++ b/arch/arm64/boot/dts/hisilicon/hi3660.dtsi
> > @@ -61,7 +61,7 @@
> >                       reg = <0x0 0x0>;
> >                       enable-method = "psci";
> >                       next-level-cache = <&A53_L2>;
> > -                     cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_0>;
> > +                     cpu-idle-states = <&CPU_SLEEP_0 &CLUSTER_SLEEP_0>;
> >                       capacity-dmips-mhz = <592>;
> >                       clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER0>;
> >                       operating-points-v2 = <&cluster0_opp>;
> > @@ -75,7 +75,7 @@
> >                       reg = <0x0 0x1>;
> >                       enable-method = "psci";
> >                       next-level-cache = <&A53_L2>;
> > -                     cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_0>;
> > +                     cpu-idle-states = <&CPU_SLEEP_0 &CLUSTER_SLEEP_0>;
> >                       capacity-dmips-mhz = <592>;
> >                       clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER0>;
> >                       operating-points-v2 = <&cluster0_opp>;
> > @@ -87,7 +87,7 @@
> >                       reg = <0x0 0x2>;
> >                       enable-method = "psci";
> >                       next-level-cache = <&A53_L2>;
> > -                     cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_0>;
> > +                     cpu-idle-states = <&CPU_SLEEP_0 &CLUSTER_SLEEP_0>;
> >                       capacity-dmips-mhz = <592>;
> >                       clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER0>;
> >                       operating-points-v2 = <&cluster0_opp>;
> > @@ -99,7 +99,7 @@
> >                       reg = <0x0 0x3>;
> >                       enable-method = "psci";
> >                       next-level-cache = <&A53_L2>;
> > -                     cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_0>;
> > +                     cpu-idle-states = <&CPU_SLEEP_0 &CLUSTER_SLEEP_0>;
> >                       capacity-dmips-mhz = <592>;
> >                       clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER0>;
> >                       operating-points-v2 = <&cluster0_opp>;
> > @@ -111,7 +111,7 @@
> >                       reg = <0x0 0x100>;
> >                       enable-method = "psci";
> >                       next-level-cache = <&A73_L2>;
> > -                     cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_1>;
> > +                     cpu-idle-states = <&CPU_SLEEP_1 &CLUSTER_SLEEP_1>;
> >                       capacity-dmips-mhz = <1024>;
> >                       clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER1>;
> >                       operating-points-v2 = <&cluster1_opp>;
> > @@ -125,7 +125,7 @@
> >                       reg = <0x0 0x101>;
> >                       enable-method = "psci";
> >                       next-level-cache = <&A73_L2>;
> > -                     cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_1>;
> > +                     cpu-idle-states = <&CPU_SLEEP_1 &CLUSTER_SLEEP_1>;
> >                       capacity-dmips-mhz = <1024>;
> >                       clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER1>;
> >                       operating-points-v2 = <&cluster1_opp>;
> > @@ -137,7 +137,7 @@
> >                       reg = <0x0 0x102>;
> >                       enable-method = "psci";
> >                       next-level-cache = <&A73_L2>;
> > -                     cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_1>;
> > +                     cpu-idle-states = <&CPU_SLEEP_1 &CLUSTER_SLEEP_1>;
> >                       capacity-dmips-mhz = <1024>;
> >                       clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER1>;
> >                       operating-points-v2 = <&cluster1_opp>;
> > @@ -149,7 +149,7 @@
> >                       reg = <0x0 0x103>;
> >                       enable-method = "psci";
> >                       next-level-cache = <&A73_L2>;
> > -                     cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP_1>;
> > +                     cpu-idle-states = <&CPU_SLEEP_1 &CLUSTER_SLEEP_1>;
> >                       capacity-dmips-mhz = <1024>;
> >                       clocks = <&stub_clock HI3660_CLK_STUB_CLUSTER1>;
> >                       operating-points-v2 = <&cluster1_opp>;
> > @@ -158,31 +158,40 @@
> >               idle-states {
> >                       entry-method = "psci";
> >
> > -                     CPU_SLEEP: cpu-sleep {
> > +                     CPU_SLEEP_0: cpu-sleep-0 {
> >                               compatible = "arm,idle-state";
> >                               local-timer-stop;
> >                               arm,psci-suspend-param = <0x0010000>;
> > -                             entry-latency-us = <40>;
> > -                             exit-latency-us = <70>;
> > -                             min-residency-us = <3000>;
> > +                             entry-latency-us = <400>;
> > +                             exit-latency-us = <650>;
> > +                             min-residency-us = <1500>;
> >                       };
> > -
> >                       CLUSTER_SLEEP_0: cluster-sleep-0 {
> >                               compatible = "arm,idle-state";
> >                               local-timer-stop;
> >                               arm,psci-suspend-param = <0x1010000>;
> >                               entry-latency-us = <500>;
> > -                             exit-latency-us = <5000>;
> > -                             min-residency-us = <20000>;
> > +                             exit-latency-us = <1600>;
> > +                             min-residency-us = <3500>;
> > +                     };
> > +
> > +
> > +                     CPU_SLEEP_1: cpu-sleep-1 {
> > +                             compatible = "arm,idle-state";
> > +                             local-timer-stop;
> > +                             arm,psci-suspend-param = <0x0010000>;
> > +                             entry-latency-us = <400>;
> > +                             exit-latency-us = <550>;
> > +                             min-residency-us = <1500>;
> >                       };
> >
> >                       CLUSTER_SLEEP_1: cluster-sleep-1 {
> >                               compatible = "arm,idle-state";
> >                               local-timer-stop;
> >                               arm,psci-suspend-param = <0x1010000>;
> > -                             entry-latency-us = <1000>;
> > -                             exit-latency-us = <5000>;
> > -                             min-residency-us = <20000>;
> > +                             entry-latency-us = <800>;
> > +                             exit-latency-us = <2900>;
> > +                             min-residency-us = <3500>;
> >                       };
> >               };
> >
> > --
> > 2.7.4
> >