android核绑定cpuset配置与检测进程所在核cpuset方法

一、开机阶段

开机有如下阶段。抛开开机动画需要的audio、surfaceflinger等进程，大部分android程序是在/data分区加载完整以后开始加载。所以cpuset的配置可以在 post-fs-data之后。注意，init.rc的不同阶段脚本都可能覆盖前面配置的cpuset。配置好检查与预期不一致，则要配置被重置了。

early-init

a) wait_for_coldboot_done

b) property_init

c) keychord_int

d) console_init

e) set_init_properties

init
early-fs
fs
post-fs
post-fs-data

f) property_service_init

g) signal_init

h) check_startup

early-boot
boot
service

二、配置cpuset

本例策略如下：

开机阶段：

write /dev/cpuset/top-app/cpus 0-5

write /dev/cpuset/foreground/cpus 0-5

write /dev/cpuset/system-background/cpus 0-5

write /dev/cpuset/background/cpus 4-5

开机完成后：

write /dev/cpuset/top-app/cpus 0-3

write /dev/cpuset/foreground/cpus 0-3

write /dev/cpuset/system-background/cpus 3-5

配置方法：

修改init.rc

on early-boot
    write /dev/cpuset/top-app/cpus 0-5
    write /dev/cpuset/foreground/cpus 0-5
    write /dev/cpuset/foreground/boost/cpus 0-5
    write /dev/cpuset/system-background/cpus 0-5
    write /dev/cpuset/background/cpus 4-5

....

on property:sys.boot_completed=1
    write /proc/sys/kernel/printk 4
    # init.vendor.rc can override below at on property:sys.boot_completed if needed
    write /dev/cpuset/top-app/cpus 0-3
    write /dev/cpuset/foreground/cpus 0-3
    write /dev/cpuset/system-background/cpus 3-5

三、配置特定进程的cpuset

# We want all cores for camera
    mkdir /dev/cpuset/camera-daemon
    write /dev/cpuset/camera-daemon/cpus 0-5
    write /dev/cpuset/camera-daemon/mems 0
    chown cameraserver cameraserver /dev/cpuset/camera-daemon
    chown cameraserver cameraserver /dev/cpuset/camera-daemon/tasks
    chmod 0660 /dev/cpuset/camera-daemon/tasks

四、验证方法：

在adb shell里面：

#cd /dev/cpuset/top-app
/dev/cpuset/top-app # ps -A -p `cat tasks`

可以看到top-app下活跃的进程

USER           PID  PPID     VSZ    RSS WCHAN            ADDR S NAME
u0_a53        2217   378 4546160 192796 ep_poll             0 S com.fiilll.app.launcher

然后敲：

ps -o pid,psr,comm -p `pidof com.gwm.fiill.launcher`

显示的PSR就是核

  PID PSR COMM
 2217   1 app_process64

同样的步骤查看system-background

/dev/cpuset/system-background # ps -A -p `cat tasks`
USER           PID  PPID     VSZ    RSS WCHAN            ADDR S NAME
logd           329     1   76160  56700 sigsuspend          0 S logd
system         330     1   11156   3728 binder_ioctl_write_read 0 S servicemanager
system         331     1 2126696   6756 binder_ioctl_write_read 0 S hwservicemanager
system         332     1   11872   3096 binder_ioctl_write_read 0 S vndservicemanager
system         474     1   56072  17740 binder_ioctl_write_read 0 S android.hardware.graphics.composer@2.2-service
root           729     1    9544   2400 ep_poll             0 S lmkd
system         731     1 2192692  34460 ep_poll             0 S surfaceflinger
system         735     1   11220   4420 poll_schedule_timeout 0 S name-server
statsd         897     1   23296   6648 ep_poll             0 S statsd
root           898     1   22688   5752 binder_ioctl_write_read 0 S storaged
root           906     1   38444  13552 poll_schedule_timeout 0 S dlt-daemon
system         954     1 2128968   7096 binder_ioctl_write_read 0 S gatekeeperd
root           955     1   18988   4752 binder_ioctl_write_read 0 S perfprofd
tombstoned     959     1    9232   2300 ep_poll             0 S tombstoned

由于statsd是开机完成前加载的，所以第一次cpuset可能在0-5之间

  PID PSR COMM
 897   0 statsd

我们以此可以判断开机时候配置的是否正常。

现在杀掉该进程重新加载：

kill -6 `pidof statsd`

再查看它的cpuset：

ps -o pid,psr,comm -p `pidof statsd`

发现cpuset已经变了

  PID PSR COMM
 9766   3 statsd