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Subject[PATCH v2] arm64: hikey960: update idle-states
Date
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 of 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(-)

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
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