Restricting the CPU or Memory Usage of a Process (Linux)

This section describes how to restrict the CPU or memory usage of ascend-deployer.

Control groups (cgroups) are a mechanism provided by the Linux kernel to restrict the resources used by a single or multiple processes. It can implement refined control on resources such as the CPU and memory. The procedure is as follows:

• Restricting the CPU usage of ascend-deployer
  1. Create a directory.

     cd /sys/fs/cgroup/cpu
     mkdir ascend-deployer         # The directory name can be customized.

     After the ascend-deployer directory is created, files such as cpu.cfs_period_us and cpu.cfs_quota_us are automatically generated in the directory.

  2. Go to the ascend-deployer directory and set the values for the corresponding file. The following files are used to restrict the CPU usage:

     Table 1 File description

     File	Description
     cpu.cfs_period_us	Period for collecting CPU usage statistics, in microseconds. The value ranges from 1000 to 1000000. The default value is 100000.
     cpu.cfs_quota_us	CPU time that can be occupied in the configured period (time of a single core, which needs to be accumulated for multiple cores during configuration). The default value is -1, indicating that the CPU time is not limited. For example, if you want to set the limit to 30%, change the value to 30000. For example, to set the maximum number of CPU cores to two, change the value to 200000.
     tasks	PID list of the processes to be restricted. For a child process derived from a PID after the restriction takes effect, the PID of the child process is automatically added to the file. You are advised to add the PID of a program's shell (by running the echo $$ command) to the tasks file and then start the program.

     For example, to set the maximum CPU usage to 50%, perform the following operations:

     Retain the default value in the cpu.cfs_period_us file and change the value in the cpu.cfs_quota_us file to 50000. In the shell window where ascend-deployer is to be run, run the echo $$ command to query the PID and write it to the tasks file.

• Restricting the memory usage of ascend-deployer
  1. Create a directory.

     cd /sys/fs/cgroup/memory
     mkdir ascend-deployer      # The directory name can be customized.

     After the ascend-deployer directory is created, files such as memory.limit_in_bytes and tasks are automatically generated in the directory.

  2. Go to the ascend-deployer directory and set the values for the corresponding file. The following files are used to restrict the CPU usage:

     Table 2 File description

     File	Description
     memory.limit_in_bytes	Limits the memory usage of a process. For example, to set the maximum memory usage to 500 MB, change the value in the memory.limit_in_bytes file to 524288000.
     tasks	PID list of the processes to be restricted. For a child process derived from a PID after the restriction takes effect, the PID of the child process is automatically added to the file. You are advised to add the PID of a program's shell (by running the echo $$ command) to the tasks file and then start the program.

     For example, to set the maximum memory usage to 500 MB, change the value in the memory.limit_in_bytes file to the calculated value 524288000. In the shell window where ascend-deployer is to be run, run the echo $$ command to query the PID and write it to the tasks file.