| Message ID | 1530860246-29072-1-git-send-email-vincent.guittot@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 06/07/2018 08:57, 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: > - 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 > - 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> > --- Great! Thanks for fixing the values. Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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 ? > - 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/ ? Except these two minor typos, the patch is very good improvement. Reviewed-by: Leo Yan <leo.yan@linaro.org> > - 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 >
Hi Leo, On 08/07/2018 16:01, leo.yan@linaro.org wrote: [ ... ] >> A simple test with a task waking up every 11,111ms shows improvement: > > Should s/11,111ms/11.111ms ? Actually the French notation is ',' for decimal :) English and French are inverted. For example one million is noted: French : 1.000.000 (or 1 000 000) English : 1,000,000 And one milli is noted: French : 0,001 English : 0.001 :) -- Daniel
On Sun, Jul 08, 2018 at 11:15:22PM +0200, Daniel Lezcano wrote: > Hi Leo, > > > On 08/07/2018 16:01, leo.yan@linaro.org wrote: > > [ ... ] > > >> A simple test with a task waking up every 11,111ms shows improvement: > > > > Should s/11,111ms/11.111ms ? > > Actually the French notation is ',' for decimal :) > > English and French are inverted. > > For example one million is noted: > > French : 1.000.000 (or 1 000 000) > English : 1,000,000 > > And one milli is noted: > > French : 0,001 > English : 0.001 > > :) Ah, interesting. Thanks for explaination, Daniel. :) Thanks, Leo Yan
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 > >
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>; }; };
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: - 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 - 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(-)