cpulimit

A tool to throttle the CPU usage of other processes. More information: http://cpulimit.sourceforge.net/.

• Limit an existing process with PID 1234 to only use 25% of the CPU:
  cpulimit --pid {{1234}} --limit {{25%}}
• Limit an existing program by its executable name:
  cpulimit --exe {{program}} --limit {{25}}
• Launch a given program and limit it to only use 50% of the CPU:
  cpulimit --limit {{50}} -- {{program argument1 argument2 ...}}
• Launch a program, limit its CPU usage to 50% and run cpulimit in the background:
  cpulimit --limit {{50}} --background -- {{program}}
• Kill its process if the program's CPU usage goes over 50%:
  cpulimit --limit 50 --kill -- {{program}}
• Throttle both it and its child processes so that none go about 25% CPU:
  cpulimit --limit {{25}} --monitor-forks -- {{program}}