CPU Time

• Wall-clock time / response time / elapsed time

  • Latency of the execution
  • how much time passes on the wall-clock for the program to finish.
  • Includes everything (OS / disc / … / other processes running)

• CPU time

  • Time where the CPU is working for your program
  • Includes User time
  • Includes System time
  • (Does not include disc fetches since the program is interruped until data arrives and started back up)
  • If program makes use of multiple cores, then cpu times of all cores is added
    • Can be bigger than elapsed time

• User time

  • Time where the CPU is executing the program

• System time

  • Time where CPU is executing OS servies for the program