R Programming By Example

Benchmarking manually with system.time()

Now, we will look into how to benchmark your code. If you're looking for a simple measurement of execution time, system.time() is a good choice. You simply call a function inside of it, and it will print the following three time measures for you: .

• user: It is the user time that we should pay more attention to, since it measures the CPU time used by R to execute the code
• system: The system time is a measure of time spent by the system to be able to execute the function
• elapsed:  The elapsed time is total time it took to execute the code, even if it was slowed down due to other system processes

Sometimes, elapsed time is longer than the sum of user time and system time because the CPU is multitasking ...