Scenario

During peak traffic hours, a background data-processing job that is started by user devops is consuming too much CPU and slowing down user-facing services. Stopping it isn't an option because it would interrupt ongoing workflows, but you need to limit its CPU usage temporarily.

Task

Reduce the process's priority to 10 while keeping it running.

Example

# Before (high priority process)

USER       PID %CPU %MEM    VSZ     RSS   TTY      STAT START   TIME COMMAND
devops    5432 85.3 12.4 2048576 256840   ?        RN   14:35   8:23 /usr/bin/data-processor --batch

# After (priority adjusted)

USER       PID %CPU %MEM    VSZ     RSS   TTY      STAT START   TIME COMMAND
devops    5432 45.2 12.4 2048576 256840   ?        RN   14:35   8:45 /usr/bin/data-processor --batch

Step 1: Identify the process PID (of the background data-processing job)

ps aux

Step 2: Check current priority/nice value (assuming the example PID we found is 5432)

ps -o pid,ni,comm -p 5432

Step 3: Reduce priority by setting nice value to 10

renice -n 10 -p 5432

Step 4: Verify the change took effect

ps -o pid,ni,comm -p 5432