差别

这里会显示出您选择的修订版和当前版本之间的差别。

--- jaysnote:linux_cooling_device [2019/04/15 14:04]
jaylee
+++ jaysnote:linux_cooling_device [2021/06/22 23:14]
@@ 行 1: / 行 1: @@
-<markdown>
-# linux cooling device
-这里详细介绍并理解基于 allwinner a64 linux 下根据[热量传感器](http://linux-sunxi.org/Thermal_Sensor) 采集的温度用以自动[调频](http://linux-sunxi.org/Cpufreq) 原理。
-## thermal sensor
-- http://linux-sunxi.org/Thermal_Sensor
-a64集两个热量传感器分别监控gpu和cpu温度。
-```bash
-The thermal sensors have become common elements in wide range of modern system on chip (SOC) platform.
-Thermal sensors are used to constantly monitor the temperature on the chip.
-A64 embeds three thermal sensors in possible hot spots on the die, sensor0 located in the CPU, sensor1 and
-sensor2 located in the GPU. The thermal sensor Generates interrupt to SW to lower temperature via DVFS, on
-reaching a certain thermal threshold
-```
-> **提示**：Allwinner_A64_User_Manual_V1.1_decrypted.pdf->3.18. Thermal Sensor Controller ->3.18.1. Overview。
-挂载在sysfs数据属性
-```bash
-pi@350-tf-s2 ~$ tree /sys/class/thermal/thermal_zone0/
-/sys/class/thermal/thermal_zone0/
-├── mode                 #enalbed 、disabled ，可读写
-├── policy               #step_wise
-├── temp                 #温度值
-├── trip_point_0_hyst    #0 看起来像一个调节范围
-├── trip_point_0_temp    #65 温度阈值
-├── trip_point_0_type    #passive
-├── ......
-├── trip_point_6_hyst    #0
-├── trip_point_6_temp    #110
-├── trip_point_6_type    #critical
-├── type                 #soc_thermal
-└── uevent
-```
-## governor
-* [ CPU frequency and voltage scaling code in the Linux(TM) kernel](https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt)
-* http://linux-sunxi.org/Cpufreq
-挂载sysfs 数据属性。
-```bash
-pi@350-tf-s2 ~$ tree /sys/devices/system/cpu/cpu0/cpufreq/
-/sys/devices/system/cpu/cpu0/cpufreq/
-├── affected_cpus                 #0 1 2 3
-├── boot_lock                     #0
-├── cpuinfo_boot_freq             #1152000
-├── cpuinfo_cur_freq
-├── cpuinfo_max_freq              #1344000
-├── cpuinfo_min_freq              #480000
-├── cpuinfo_transition_latency    #2000000
-├── related_cpus                  #0 1 2 3
-├── scaling_available_frequencies #480000 600000 720000 816000 1008000 1104000 1152000 1200000 1344000
-├── scaling_available_governors   #interactive conservative ondemand userspace powersave performance
-├── scaling_cur_freq              #当前cpu频率
-├── scaling_driver                #cpufreq-sunxi
-├── scaling_governor              #ondemand
-├── scaling_max_freq              #调节范围最大值
-├── scaling_min_freq              #调节范围最小值
-├── scaling_setspeed              #<unsupported>
-└── stats
-    ├── time_in_state
-    ├── total_trans
-    └── trans_table
-```
-## cooling device
-挂载在sysfs数据属性
-```bash
-pi@350-tf-s2 ~$ tree /sys/class/thermal/cooling_device0
-/sys/class/thermal/cooling_device0
-├── cur_state                  # 0当前状态值，可写，写入该状态值直接影响CPU主频变化
-├── max_state                  #6 最大值
-├── power
-│   ├── async
-│   ├── autosuspend_delay_ms
-│   ├── control
-│   ├── runtime_active_kids
-│   ├── runtime_active_time
-│   ├── runtime_enabled
-│   ├── runtime_status
-│   ├── runtime_suspended_time
-│   └── runtime_usage
-├── subsystem -> ../../../../class/thermal
-├── type
-└── uevent
-```
-`/var/log/syslog` 日志分析
-```bash
-kernel: [239144.300372] CPU Budget:update CPU 0 cpufreq max to 816000 min to 480000
-kernel: [239144.302585] CPU Budget hotplug: cluster0 min:0 max:4
-kernel: [239144.792365] CPU Budget:update CPU 0 cpufreq max to 1008000 min to 480000
-kernel: [239144.794593] CPU Budget hotplug: cluster0 min:0 max:4
-kernel: [239145.776364] CPU Budget:update CPU 0 cpufreq max to 816000 min to 480000
-kernel: [239145.778579] CPU Budget hotplug: cluster0 min:0 max:4
-```
-如上日志表示基于cpu核心温度变化自动调节了cpu主频最大值。
-## test script
-如下代码片段设计：
-* 设计cpu压力测试（温度高会自自动调频）；
-* 增加手动切换调频；
-* 实时打印温度、频率范围、当前频率值；
-* 可以尝试去掉cpu自动调频；
-```bash
-# !/bin/bash
-[ -f /usr/bin/bc ] || {
-    wget https://mirrors.sohu.com/debian/pool/main/b/bc/bc_1.06.95-9_arm64.deb
-    sudo dpkg -i bc_1.06.95-9_arm64.deb
-}
-#cpu pressure test
-echo "scale=500000; 4*a(1)" | bc -l -q &
-echo "scale=500000; 4*a(1)" | bc -l -q &
-echo "scale=500000; 4*a(1)" | bc -l -q &
-echo "scale=500000; 4*a(1)" | bc -l -q &
-echo "disabled" |sudo tee /sys/class/thermal/thermal_zone0/mode
-echo 4 |sudo tee /sys/class/thermal/cooling_device0/cur_state
-let flag=1
-while [ 1 ]
-do
-    if [ $flag -eq 0 ];then
-        let flag=1
-        echo 2 |sudo tee /sys/class/thermal/cooling_device0/cur_state
-    else
-        let flag=0
-        echo 3 |sudo tee /sys/class/thermal/cooling_device0/cur_state
-    fi
-    echo -e "\033[32m$(date) \033[0m"
-    echo "temp: $(cat /sys/class/thermal/thermal_zone0/temp)"
-    echo "cur_state: $(cat /sys/class/thermal/cooling_device0/cur_state)"
-    echo "min_freq: $(cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq)"
-    echo "max_freq: $(cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq)"
-    echo "cur_freq: $(sudo cat  /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq)"
-    top -bn 1 -i -c |head -n 5
-    echo ""
-    sleep 1
-done
-```
-</markdown>

文档中心

用户工具

站点工具

差别

页面工具