27.7. 在引导过程中更改服务优先级

流程

1. 查看正在运行的线程的调度优先级：

   # tuna --show_threads
       thread       ctxt_switches
       pid SCHED_ rtpri affinity voluntary nonvoluntary             cmd
     1      OTHER     0     0xff      3181          292         systemd
     2      OTHER     0     0xff       254            0        kthreadd
     3      OTHER     0     0xff         2            0          rcu_gp
     4      OTHER     0     0xff         2            0      rcu_par_gp
     6      OTHER     0        0         9            0 kworker/0:0H-kblockd
     7      OTHER     0     0xff      1301            1 kworker/u16:0-events_unbound
     8      OTHER     0     0xff         2            0    mm_percpu_wq
     9      OTHER     0        0       266            0     ksoftirqd/0
   [...]

2. 创建附加 mcelog 服务配置目录文件，并在此文件中插入策略名称和优先级：

   # cat << EOF > /etc/systemd/system/mcelog.service.d/priority.conf
   
   [Service]
   CPUSchedulingPolicy=fifo
   CPUSchedulingPriority=20
   EOF

3. 重新载入 systemd 脚本配置：

   # systemctl daemon-reload

4. 重启 mcelog 服务：

   # systemctl restart mcelog